Efficient Electrochemical N -Alkylation of N -Boc-Protected 4-Aminopyridines: Towards New Biologically Active Compounds

Research ArticleEfficient Electrochemical N-Alkylation of N-Boc-Protected4-Aminopyridines Towards New Biologically Active Compounds

Marta Feroci1 Isabella Chiarotto1 Gianpiero Forte1 Giovanna Simonetti2

Felicia Diodata DrsquoAuria2 Louis Maes3 Daniela De Vita4 Luigi Scipione4 Laura Friggeri4

Roberto Di Santo4 and Silvano Tortorella4

1 Department of Basic and Applied Sciences for Engineering Sapienza University of Rome Via Castro Laurenziano 7 00161 Rome Italy2 Department of Public Health and Infectious Diseases Sapienza University of Rome Piazzale Aldo Moro 5 00185 Rome Italy3 Laboratory for Microbiology Parasitology and Hygiene (LMPH) Faculty of Pharmaceutical Biomedical and Veterinary SciencesAntwerp University 2610 Antwerp Belgium

4 ldquoIstituto Pasteur-Fondazione Cenci Bolognettirdquo Department of ldquoChimica e Tecnologie del Farmacordquo Sapienza University of RomePiazzale Aldo Moro 5 00185 Rome Italy

Correspondence should be addressed to Marta Feroci martaferociuniroma1it

Received 22 November 2013 Accepted 21 January 2014 Published 5 March 2014

Academic Editors L Palombi and R Pohl

Copyright copy 2014 Marta Feroci et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

The use of electrogenerated acetonitrile anion allows the alkylation of N-Boc-4-aminopyridine in very high yields under mildconditions andwithout by-productsThehigh reactivity of this base is due to its large tetraethylammoniumcounterion which leavesthe acetonitrile anion ldquonakedrdquo The deprotection of the obtained compounds led to high yields in N-alkylated 4-aminopyridinesNonsymmetrically dialkylated 4-aminopyridines were obtained by subsequent reaction of monoalkylated ones with t-BuOK andalkyl halides while symmetrically dialkylated 4-aminopyridines were obtained by direct reaction of 4-aminopyridinewith an excessof t-BuOK and alkyl halides Some mono- and dialkyl-4-aminopyridines were selected to evaluate antifungal and antiprotozoalactivity the dialkylated 4-aminopyridines 3ac 3ae and 3ff showed antifungal towards Cryptococcus neoformans whereas 3cc 3eeand 3ff showed antiprotozoal activity towards Leishmania infantum and Plasmodium falciparum

1 Introduction

N-Alkylated 4-aminopyridine is a commonmoiety in biolog-ically active molecules It is present in fact in compoundswith different activities such as inhibitors of p38120572 MAPkinase [1] inhibitors of HIV-EP1 cellular transcription factor[2] inhibitors of coagulation Factor Xa [3] and 120573-chemokinereceptor CCR5 antagonists in anti-HIV therapy [4] inparticular we have focused our work on the developmentof new CYP51 inhibitors active both on fungal strains [5]and Trypanosoma Cruzi [6] Many literature data evidencedthat the pyridine group can efficaciously replace the heme-iron chelating azole moiety present in classical azole CYP51inhibitors and therefore the alkylation of 4-aminopyridine(4AP) represents an important goal in organic synthesis todevelop novel classes of antifungal and antiparasitic drugs[7 8]

Due to the wide presence of these products the alkylationof 4-aminopyridine (4AP) is therefore an important goal inorganic synthesis

Different approaches to obtainN-alkylated 4-aminopyri-dines have been reported in the literature Some examplesare the efficient condensation of 4AP with alcohols catalyzedby benzaldehyde [9] or copper [10 11] or magnetite [12] thereaction of 4AP with an acyl chloride and the followingreduction of the amide with LiAlH

4[13]

The most straightforward method however is the directalkylation of 4AP with alkyl halides although it suffersfrom some drawbacks The two different nitrogen atomscompete in the alkylation reaction and usually the morenucleophilic pyridine nitrogen atom reacts faster leading tothe corresponding pyridinium salt (Scheme 1) [14 15]

In these case the use of a very strong base is therefore nec-essary n-BuLi was successfully used by Singh and coworkers

Hindawi Publishing CorporationISRN Organic ChemistryVolume 2014 Article ID 621592 10 pageshttpdxdoiorg1011552014621592

2 ISRN Organic Chemistry

NN Slow FastH2N H2N +

Xminus

RndashNH NndashRRndashX RndashX

Scheme 1 Reaction of 4-aminopyridine with alkyl halides

[16] obtaining N-methyl- and N-ethyl-4-aminopyridines in74ndash80 yields

A viable alternative is the enhancement of the nucle-ophilicity of the amine nitrogen atom (versus the pyridineone) allowing the use of weaker bases An example is theactivation of 2-aminopyridine as formyl or Boc derivativeat the amine nitrogen atom [17] with subsequent deproto-nation using sodium hydride alkylation and deprotectionwith trifluoroacetic acid The deprotonation of N-Boc-2-aminopyridine with NaH needs a careful control of thetemperature (0ndash5∘C) and is carried out in anhydrous DMFwith a vigorous stirring required to keep the suspension fluid

In this context we envisaged the possibility to alkylateN-Boc-4-aminopyridine (N-Boc-4AP) usingmilder reactionconditions that is using electrogenerated tetraethylammo-nium cyanomethanide (Et4N+minusCH

2CN) [18] This base the

acetonitrile anion can be easily obtained by cathodic gal-vanostatic reduction of a solution of acetonitrile contain-ing tetraethylammonium hexafluorophosphate as supportingelectrolyte (Scheme 2) without by-products (the reagent isthe electron) and it was successfully used by us in a goodvariety of reactions [19] such as the selective N-alkylationof bifunctional compounds [20] the Gewald reaction [21]the synthesis of 120573-lactams [22] and the synthesis of car-bamates [23] The actual mechanism for the formation ofacetonitrile anion is not known but a hypothesis based onthe direct reduction of the tetraethylammonium cation hasbeen reported (Scheme 2) [24]

The high reactivity of this base is ascribable to thelarge tetraethylammonium counterion which renders theacetonitrile anion extremely reactive Moreover its reactionas a base gives no by-products as the protonation restores themolecule of solvent

2 Results and Discussion

The reaction of electrogenerated acetonitrile anion with4AP followed by an alkyl halide leads to poor yields indesired compound with the pyridinium salt being the majorproduct This prevents the direct use of minusCH

2CN with 4AP

On the other hand if the amine nitrogen is activated asBoc derivative (N-Boc-4AP) the deprotonationalkylationreaction using acetonitrile anion leads to products 1 in veryhigh yields (Scheme 3 and Table 1 entries 1ndash6) The classicdeprotection with trifluoroacetic acid allows obtaining thedesired products 2 (Scheme 3 and Table 1 entries 1ndash6)

The data in Table 1 highlight that the reaction of depro-tonation of N-Boc-4AP using electrogenerated acetonitrileanion alkylation with both alkyl and benzyl halides anddeprotection with trifluoroacetic acid is very efficient withoverall yields of 78ndash86 However when the alkylating agentis a bromoacetophenone the yields in alkylated product are

lower and inmost cases the deprotection reaction leads to thedealkylation of the starting material (Table 1 entries 7ndash10)

As many biologically active compounds contain thedialkylated 4-aminopyridine moiety we tried to carry out asecond alkylation on products 2andashj using acetonitrile anionbut as expected the high nucleophilicity of the pyridinenitrogen led to the synthesis of the corresponding pyridiniumsalt

We thus carried out this second alkylation using strongbases the most efficient being t-BuOK in DMSO (Scheme 4)although the yields in dialkylated 4AP were not very highThe results of this reaction are reported in Table 2

In order to obtain symmetrically dialkylated 4AP 4APwas subjected to deprotonation with t-BuOK in DMSOadding an excess of alkylating agent The reaction led toa mixture of mono- and dialkylated 4-aminopyridines inmoderate to acceptable yields The results are reported inTable 3

3 Biological Activity

A selection of synthesized compounds was in vitro testedto evaluate antifungal activity against different strains of Calbicans C parapsilosis and Cryptococcus neoformans dataare reported in Table 4 As can be evidenced the nonsym-metrical dialkylated 4APs 3ac and 3ae showed a moderateantifungal activity towards C albicans and C parapsilosiswith MIC

50values of 32 120583gmL and showed an interesting

activity against Cryptococcus neoformans with MIC50values

of 04 and 4 120583gmL respectively Otherwise the symmetricaldialkylated 4APs 3cc 3ee and the Boc-protected monoalky-lated 4APs 1b 1e 1f showed poor antifungal activity withMIC50and MIC

100ge 64 120583gmL

Furthermore the symmetrical dialkylated 4APs 3cc 3eeand 3ff were in vitro tested to evaluate the activity againstTry-panosoma cruzi Trypanosoma brucei Leishmania infantumand Plasmodium falciparum the results are summarized inTable 5

As can be evidenced all tested compounds showed amoderate activity versus P falciparum and an interestingactivity towards L infantum with IC

50values lower than the

reference drug miltefosine otherwise they resulted scarcelyactive against T cruzi and T brucei Moreover these com-pounds also showed low toxic activity versus growingMRC-5cells

4 Conclusion

In conclusion we demonstrated the usefulness of electro-generated acetonitrile anion in the alkylation of N-Boc 4-aminopyridines both from the point of viewof the high yieldsand of the cleanliness of the reaction (no by-products) Thedeprotection of N-Boc 4-aminopyridines allowed obtainingmonoalkylated 4-aminopyridine in very high yields Thefollowing alkylation by means of t-BuOK and alkyl halidesled to nonsymmetrically dialkylated 4-aminopyridine whilesymmetrically dialkylated products were obtained directlyfrom 4-aminopyridine by reaction with an excess of t-BuOKand alkyl halide

ISRN Organic Chemistry 3

Table 1 Alkylation reaction of 119873-Boc-4AP using electrogenerated acetonitrile anion in MeCN-01M TEAHFP followed by deprotectionwith trifluoroacetic acida

Entry RndashX 1 yield 2 yield

1 Br6N

NBoc

6

1a gt95

N

HN 6

2a 91

2Br

N

NBoc

Ph

1b 85

N

HN Ph

2b 93

3Cl

N

NBoc

1c 85

N

HN

2c gt95

4 Br

Cl

Cl N

NBoc

Cl

Cl

1d 95

N

HN

Cl

Cl

2d 91

5Br

FN

NBoc

F

1e 93

N

HN

F

2e 90

6Br

F3C N

NBoc

CF3

1f 90

N

HN

CF3

2f 87

7

OBr

N

NBoc

O

1g 34N

HNO

2g trb


Table 1 Continued


8

OBr

FN

NBoc

O

F

1h 38

N

HNO

F

2h trb

9

OBr

ClN

NBoc

O

Cl

1i 56

N

HNO

Cl

2i trb

10

OBr

ON

NBoc

O

O

1j 48

N

HNO

O

2j 73aThe reduction was conducted under galvanostatic conditions (20mA cmminus2) on Pt electrodes in a divided cell at rt on 20mLMeCN-01M TEAHFP solutioncontaining 1mmol of 4AP At the end of the electrolysis 1mmol of alkylating agent was added After 2 h at rt usual workup afforded the products Deprotectionwas carried out as described in the experimental part All the yields are in isolated products bWhen compounds 2gndashi were subjected to deprotection withtrifluoroacetic acid a large amount of 4AP was obtained

Overall reaction Possible mechanism

CH3CNEt4N-PF6 Et4N+minusCH2CN Et4N++ eminus

Et4N∙

Et4N∙

Et∙ + eminus

Etminus + CH3CNEtminus

minusCH2CN

Et3N + Et∙+eminus

Scheme 2 Electrogeneration of acetonitrile anion

N N

NHBoc

N

NBoc R

N

HNR

4AP N-Boc-4AP

NH2

(Boc)2OCH3CN rt

(1)

(2)

minusCH2CN CF3CO2HCH2Cl2RndashX

1andashj 2andashj

Scheme 3 Synthesis of N-alkyl-4-aminopyridine

Furthermore it can also be concluded that themonoalky-lation of the 4AP leads to inactive products and otherwiseinteresting activity against fungi and some protozoa can beobtained by dual symmetrical or nonsymmetrical dialkyla-

N

HNR

2N

NR

(1) t-BuOK DMSO rt

R998400

3

(2) R998400ndashX

Scheme 4 Alkylation of 4-alkylaminopyridine

tion of the amino group of 4AP these activemolecules can beconsidered as lead compound to develop new antifungal andantiprotozoal compounds


Table 2 Alkylation reaction of 4-alkylaminopyridines with 119905-BuOK in DMSOa

Entry Starting 2 R1015840ndashX 3 yieldb

1N

HN

2a

6

Cl

N

N 6

3ac 29

2N

HN

2c

Br6N

N 6

3ac 34

3N

HN

2e

F Br6N

N 6

F

3ae 24

4N

HN

2e

F Br

N

N

F

3be 31a1mmol of 2 in 2mL of anhydrous DMSO at rt under N2 Then 15mmol of 119905-BuOK were added followed by 1mmol of halide after 20min The reaction waskept under stirring for 4 h bAll the yields are in isolated products

5 Materials and Methods

51 General Acetonitrile was distilled twice from P2O5and

CaH2 Commercially available reagents were used without

further purification The Boc protection of 4-aminopyridinewas carried out following the literature [25]

4-[N-(tert-Butoxycarbonyl)amino]pyridine N-Boc-4AP To asolution of di-tert-butyl dicarbonate (3mmol) in acetonitrile(3 cm3) at room temperature 4-aminopyridine (3mmol) wasslowly added This mixture was then allowed to stir for 3 h atroom temperatureThe solvent was evaporated and the crude4-[N-(tert-butoxycarbonyl)amino]pyridine (gt95)was usedin the electrolyses without further purification Rf (30 ethylacetate in light petroleum ether) 020 1H NMR (200MHzCDCl

3) 120575 153 (s9H) 69 (bs 1H) 732 (dd 119869 = 48 16Hz

2H) 845 (dd 119869 = 48 16Hz 2H) 13C NMR (50MHzCDCl

3) 120575 282 817 1123 1456 1503 1519 EIMS mz 194

(M+ 1) 137 (2) 121 (5) 120 (8) 94 (50) 78 (4) 57(100)

52 Electrochemical ALkylation of N-Boc-4AP Constant cur-rent electrolyses (I = 25mA cmminus2) were performed undera nitrogen atmosphere at 20∘C using an Amel Model 552

potentiostat equipped with an Amel Model 731 integratorAll the experiments were carried out in a divided glasscell separated through a porous glass plug filled up witha layer of gel (ie methyl cellulose 05 volume dissolvedin DMF-Et

4NPF610mol dmminus3) Pt spirals (apparent areas

08 cm2) were used both as cathode and anode MeCN-Et4NPF601mol dmminus3 was used as solvent-supporting elec-

trolyte system (catholyte 20 cm3 anolyte 5 cm3) 1mmol ofN-Boc-4-aminopyridine was present in the catholyte After145 C were passed the current was switched off and 1mmolof alkylating agent was added to the catholyte The solutionwas kept under stirring at room temperature for 2 hours thenthe solvent was evaporated under reduced pressure and theresiduewas purified by flash column chromatography using amixture of ethyl acetatelight petroleum ether 28 in volumeobtaining the pure products

Flash column chromatography was carried out usingMerck 60 kieselgel (230ndash400 mesh) under pressure GC-MSmeasurements were carried out on SE 54 capillary columnusing a Fisons 8000 gas chromatograph coupled with aFisons MD 800 quadrupole mass selective detector 1H and13C NMR spectra were recorded at room temperature usinga Bruker AC 200 spectrometer using CDCl

3as internal

standard


Table 3 Dialkylation reaction of 4-aminopyridine with 119905-BuOK in DMSOa

Entry RndashX 3 yieldb

1Br

N

N

3bb 36

2Cl

N

N

3cc 42

3Br

F N

N

F F

3ee 39

4Br

F3C N

N

CF3

3ff 65

F3C

a1mmol of 4AP in 2mL of anhydrous DMSO at rt under N2 Then 2mmol of 119905-BuOK were added followed by 2mmol of halide after 20min The reactionwas kept under stirring for 4 h bAll the yields are in isolated products

Table 4 Antifungal activity of selected 4APsa

Compound Candida albicans (3 strains) Candida parapsilosis ATCC22019 Cryptococcus neoformans (2 strains)MIC50 (120583gmL) MIC100 (120583gmL) MIC50 (120583gmL) MIC100 (120583gmL) MIC50 (120583gmL) MIC100 (120583gmL)

1b gt64 gt64 gt64 gt64 nd nd1e gt64 gt64 gt64 gt64 nd nd1f gt64 gt64 gt64 gt64 nd nd2e gt64 gt64 64 gt64 nd nd2f gt64 gt64 gt64 gt64 nd nd3ac 113b 269b 32 32 04c nd3ae 269b 32b nd nd 4c nd3cc gt64 gt64 gt64 gt64 64 gt643ee gt64 gt64 gt64 gt64 32 643ff gt64 gt64 gt64 gt64 8 32Fluconazole 1 nd 2 nd 2 ndAmphotericin B nd 079 nd 1 nd 05aThe values are expressed as geometric mean of minimum inhibitory concentration (MIC) determined using Clinical and Laboratory Standard Institute(CLSI) protocol M27-A3 MIC50 lowest drug concentration that prevented 50 of growth with respect to the untreated control control MIC100 lowest drugconcentration that prevented 100 of growth with respect to the untreated control b8Candida albicans strains were tested c4 Cryptococcus neoformans strainswere tested


Table 5 Anti-parasitic activity of selected di-alkylated 4APs

T cruziaIC50 120583M

T bruceibIC50 120583M

L infcIC50 120583M

Pf-K1dIC50 120583M

MRC-5IC50 120583M

Reference drug Benznidazole(IC50 = 195)

Suramine(IC50 = 002)

Miltefosine(IC50 = 104)

Chloroquine(IC50 = 014)

Tamoxifen(IC50= 152)

3cc 2016 3154 806 159 39013ee 957 2823 864 187 30093ff 244 662 216 133 765aT cruziTulahuenC4 amastigote stage bT brucei rhodesiense STIB 900 trypomastigote stage cL donovaniMHOM-ET-67L82 amastigote stage dP falciparumK1 IEF

tert-Butyl (octyl)pyridin-4-ylcarbamate 1a Rf (80 ethylacetate in dichloromethane) 060 1H NMR (200MHzCDCl

3) 120575 088 (t 119869 = 65Hz 3H) 120ndash130 (m 10H)

149ndash186 (m 3H) 150 (s 9H) 369 (app t 119869 = 76Hz 2H)724 (dd 119869 = 62 16Hz 2H) 851 (dd 119869 = 62 16Hz 2H)13C NMR (50MHz CDCl

3) 120575 140 226 267 282 284 291

317 487 814 1188 1500 1501 1534

tert-Butyl (3-phenylpropyl)pyridin-4-ylcarbamate 1b Rf(50 ethyl acetate in light petroleum ether) 046 1H NMR(200MHz CDCl

3) 120575 148 (s 9H) 186ndash202 (m 2H) 264

(t 119869 = 76Hz 2H) 374 (app t 119869 = 76Hz 2H) 712ndash733(m 7H) 849 (dd 119869 = 48 16Hz 2H) 13C NMR (50MHzCDCl

3) 120575 282 300 330 483 816 1189 1261 1283 1285

1410 1497 1503 1534 EIMSmz M+ absent 212 (5) 107(100) 105 (5) 91 (25) 78 (27) 77 (12)

tert-Butyl (benzyl)pyridin-4-ylcarbamate 1c Rf (60 ethylacetate in light petroleum ether) 058 1H NMR (200MHzCDCl

3) 120575 145 (s 9H) 494 (s 2H) 720ndash737 (m 7H) 846

(dd 119869 = 48 16Hz 2H) 13C NMR (50MHz CDCl3) 120575 281

525 821 1182 1263 1273 1287 1377 1502 1501 1535EIMS mz M+ absent 227 (4) 183 (14) 91 (100) 78(7) 57 (51)

tert-Butyl (26-dichlorobenzyl)pyridin-4-ylcarbamate 1d Rf(50 ethyl acetate in light petroleum ether) 060 1H NMR(200MHz CDCl

3) 120575 148 (s 9H) 529 (s 2H) 702ndash721

(m 5H) 841 (dd 119869 = 48 16Hz 2H) 13C NMR (50MHzCDCl

3) 120575 282 467 817 1215 1286 1295 1317 1361 1481

1499 1533 EIMSmz 352 (M+ 1) 252 (3) 163 (6) 161(30) 159 (42) 78 (76) 51 (100)

tert-Butyl (4-fluorobenzyl)pyridin-4-ylcarbamate 1e Rf(50 ethyl acetate in light petroleum ether) 049 1H NMR(200MHz CDCl

3) 120575 145 (s 9H) 489 (s 2H) 697ndash722

(m 6H) 847 (app d 119869 = 60Hz 2H) 13C NMR (50MHzCDCl

3) 120575 281 518 822 1166 (d 119869 = 215Hz) 1184 1281

(d 119869 = 80Hz) 1334 (d 119869 = 32Hz) 1499 1503 15341622 (d119869 = 2454Hz) EIMS mz 302 (M+ 1) 245 (4)201 (53) 108 (100) 78 (42) 57 (100)

tert-Butyl (4-trifluoromethylbenzyl)pyridin-4-ylcarbamate 1fRf (50 ethyl acetate in light petroleum ether) 041 1HNMR(200MHz CDCl

3) 120575 146 (s 9H) 499 (s 2H) 720ndash736 (m

4H) 761 (app d 119869 = 84Hz 2H) 849 (app d 119869 = 62Hz2H) 13C NMR (50MHz CDCl

3) 120575 281 522 825 1181

1240 (q 119869 = 2719Hz) 1257 (q 119869 = 37Hz) 1266 1297(q 119869 = 323Hz) 1419 1498 1504 1533 EIMS mz M+absent 251 (9) 158 (34) 145 (2) 78 (25) 69 (9) 57(100)

tert-Butyl (2-oxo-2-phenylethyl)pyridin-4-ylcarbamate 1 gRf (60 ethyl acetate in light petroleum ether) 050 1HNMR (200MHz CDCl

3) 120575 146 (s 9H) 509 (s 2H) 726

(d 119869 = 64Hz 2H) 748ndash768 (m 3H) 799 (d 119869 = 82Hz2H) 847ndash855 (m 2H) 13C NMR (50MHz CDCl

3) 120575 281

555 825 1187 1279 1289 1339 1347 1502 1532 1937

tert-Butyl (2-(4-fluoropheny)-2oxoethyl)pyridin-4-ylcarbam-ate 1 h Rf (50 ethyl acetate in light petroleum ether)050 1H NMR (200MHz CDCl

3) 120575 146 (s 9H) 505 (s

2H) 715ndash727 (m 4H) 799ndash806 (m 2H) 852 (dd J = 5014Hz 2H) 13C NMR (50MHz CDCl

3) 120575 281 554 826

1162 (d 119869 = 220Hz) 1188 1306 (d 119869 = 94Hz) 1311(d 119869 = 32Hz) 1501 1502 1532 1662 (d 119869 = 2561Hz)1922

tert-Butyl (2-(4-chloropheny)-2oxoethyl)pyridin-4-ylcarbam-ate 1i Rf (20 ethyl acetate in dichloromethane) 030 1HNMR (200MHz CDCl

3) 120575 145 (s 9H) 504 (s 2H) 721

(dd 119869 = 46 16Hz 2H) 750 (d 119869 = 88Hz 2H) 793(d 119869 = 80Hz 2H) 851 (dd 119869 = 46 16Hz 2H) 13C NMR(50MHz CDCl

3) 120575 281 554 826 1188 1293 1330 1405

1499 1503 1531 1927

tert-Butyl (2-(4-methoxypheny)-2oxoethyl)pyridin-4-ylcarb-amate 1j Rf (40 ethyl acetate in dichloromethane) 0501HNMR (200MHz CDCl

3) 120575 146 (s 9H) 390 (s 3H) 504

(s 2H) 699 (d 119869 = 90Hz 2H) 724 (dd 119869 = 48 16Hz2H) 797 (d 119869 = 90Hz 2H) 850 (dd 119869 = 48 16Hz 2H)13CNMR (50MHz CDCl

3) 120575 281 551 555 823 1141 1187

1278 1302 1502 1533 1641 1920

53 Deprotection of Compounds 1andashj To a solution of 1(1mmol) in CH

2Cl2(5 cm3) kept at 0∘C 1 cm3 of CF

3COOH

was addedThismixture was allowed to stir for 3 h at 0∘CThesolution was then mixed with aqueous sodium carbonatetill pH 8 and extracted with ethyl acetate The solvent


was removed under reduced pressure and the mixture waspurified by flash chromatography yielding pure compound 2

N-(Octyl)pyridin-4-amine 2a Rf (20 dichloromethane inethyl acetate) 016 1HNMR (200MHz CDCl

3) 120575 089 (t 119869 =

72Hz 3H) 125ndash134 (6H) 161ndash170 (m 2H) 289ndash312 (m2H) 315ndash324 (m 2H) 543ndash548 (m 2H) 657 (d 119869 =52Hz 2H) 811 (d 119869 = 52Hz 2H) 13C NMR (50MHzCDCl

3) 120575 141 226 270 288 292 292 318 429 1074 1552

N-(3-Phenylpropyl)pyridin-4-amine 2b Rf (ethyl acetate)046 1H NMR (200MHz CD

3CN) 120575 191ndash206 (m 2H) 271

(t 119869 = 74Hz 2H) 317ndash327 (m 2H) 49 (bs 1H) 662ndash666(m 2H) 714ndash746 (m 5H) 745ndash797 (m 2H) 13C NMR(50MHz CD

3CN) 120575 298 325 420 1073 1259 1283 1284

1410 1415 1578 EIMS mz 212 (M+ 1) 107 (100) 91(43) 78 (13)

N-(Benzyl)pyridin-4-amine 2c Rf (ethyl acetate) 057 1HNMR (200MHz CDCl

3) 120575 446 (d 119869 = 60Hz 2H) 67 (bs

2H) 71 (bs 1H) 721ndash741 (m 5H) 80 (bs 2H) 13C NMR(50MHz CDCl

3) 120575 468 1074 1272 1276 1288 1377 1486

1540 EIMS mz 184 (M+ 15) 183 (15) 107 (5) 91(100) 78 (16)

N-(26-Dichlorobenzyl)pyridin-4-amine 2d Rf (ethyl acetate)038 1HNMR (200MHz CD

3CN) 120575459 (s 2H) 60 (bs 1H)

668 (dd 119869 = 52 14Hz 2H) 727ndash747 (m 3H) 841 (appd 119869 = 54 Hz 2H) 13C NMR (50MHz CD

3CN) 120575 422

1074 1287 1304 1328 1360 1473 1546 EIMS mz 256(M+ + 4 1) 254 (M+ + 2 7) 252 (M+ 14) 162 (10)160 (67) 158 (100) 78 (37)

N-(4-Fluorobenzyl)pyridin-4-amine 2e Rf (ethyl acetate)027 1H NMR (200MHz CDCl

3) 120575 438 (d J = 54Hz 2H)

51 (bs 1H) 65 (bs 2H) 702ndash710 (m 2H) 730ndash734 (m 2H)82 (bs 2H) 13C NMR (50MHz CDCl

3) 120575 463 1078 1158

(d 119869 = 215Hz) 1290 (d 119869 = 81Hz) 1331 1485 1538 1668(d 119869 = 2059Hz) EIMS mz 202 (M+ 5) 107 (16) 109(100) 78 (16)

N-(4-Trifluoromethylbenzyl)pyridin-4-amine 2f Rf (ethylacetate) 025 1H NMR (200MHz CDCl

3) 120575 451 (d 119869 =

60Hz 2H) 62 (bs 1H) 66 (bs 2H) 754 (d 119869 = 80Hz2H) 767 (d 119869 = 80Hz 2H) 81 (bs 2H) 13CNMR (50MHzCDCl

3) 120575 454 1078 1244 (q 119869 = 2710Hz) 1254 (q 119869 =

39Hz) 1284 (q J = 319Hz) 1277 1432 1467 1550 EIMSmz 252 (M+ 80) 183 (11) 159 (100) 107 (52) 78(31)

1-(4-Methoxyphenyl)-2-(pyridin-4-ylamine)ethan-1-one 2 gRf (50 ethyl acetate in ethanol) 015 1H NMR (200MHzCDCl

3) 120575 390 (s 3H) 457 (d 119869 = 38Hz 2H) 46 (bs

1H) 658 (d J = 62Hz 2H) 698 (d 119869 = 90Hz 2H) 798(d 119869 = 90Hz 2H) 819 (d 119869 = 62Hz 2H) 13C NMR(50MHz CDCl

3) 120575 482 556 1081 1141 1272 1302 1508

1536 1645 1916

54 Alkylation of Compounds 2ace To a solution of 2(1mmol) in anhydrous DMSO (2 cm3) kept at rt under N

2

15mmol of t-BuOK was added This mixture was allowedto stir for 20min at rt then 1mmol of alkyl halide wasadded and the solution was kept under stirring at rt for4 h The solution was then mixed with water and extractedwith dichloromethane The solvent was removed underreduced pressure and the mixture was purified by flashchromatography yielding pure compound 3

N-Benzyl-N-octylpyridin-4-amine 3ac Rf (80 ethyl acetatein ethanol) 038 1H NMR (200MHz CDCl

3) 120575 086ndash092

(m 3H) 120ndash140 (m 10H) 163ndash170 (m 2H) 342 (appt 119869 = 76Hz 2H) 459 (s 2H) 651 (d 119869 = 52Hz2H) 714ndash738 (m 5H) 818 (d 119869 = 52Hz 2H) 13CNMR (50MHz CDCl

3) 120575 141 226 269 270 292 294

297 318 507 534 1069 1262 1273 1288 1368 1489 1536

N-(4-Fluorobenzyl)-N-octylpyridin-4-amine 3ae Rf (ethylacetate) 040 1H NMR (200MHz CDCl

3) 120575 086ndash092

(m 3H) 123ndash135 (m 10H) 162ndash172 (m 2H) 342 (appt 119869 = 78Hz 2H) 458 (s 2H) 656 (app d 119869 = 64Hz2H) 699ndash716 (m 4H) 817 (app d 119869 = 64Hz 2H) 13CNMR (50MHz CDCl

3) 120575 141 192 226 269 292 293 317

513 533 1074 1161 (d 119869 = 217Hz) 1279 (d J = 81Hz)1309 (d 119869 = 35Hz) 1449 1553 1623 (d 119869 = 2465Hz)

N-(4-Fluorobenzyl)-N-(3-phenylpropyl)pyridin-4-amine 3beRf (ethyl acetate n-hexane methanol 50 33 17) 048 1HNMR (200MHz CDCl

3) 120575 191ndash203 (m 2H) 268 (t 119869 =

74Hz 2H) 343 (app t J = 78Hz 2H) 454 (s 2H) 644(app d 119869 = 54Hz 2H) 696ndash736 (m 9H) 815 (bs 2H)13CNMR (50MHz CDCl

3) 120575 281 330 499 529 1068 1158

(d 119869 = 216Hz) 1263 1279 (d 119869 = 80Hz) 1283 12861321 (d 119869 = 32Hz) 1407 1479 1537 1621 (d J =2458Hz)

55 Dialkylation of 4-Aminopyridine To a solution of 4AP(1mmol) in anhydrous DMSO (2 cm3) kept at rt under N

2


NN-Di(3phenylpropyl)pyridin-4-amine 3bb Rf (80 ethylacetate in dichloromethane) 020 1H NMR (200MHzCD3CN) 120575 184ndash199 (m 4H) 265 (t 119869 = 75Hz 4H) 329

(t 119869 = 75Hz 4H) 630 (d 119869 = 56Hz 2H) 717ndash731(m 10H) 813 (d 119869 = 56Hz 2H) 13C NMR (50MHzCD3CN) 120575 283 331 495 1064 1262 1283 1285 1411

1407 1524

NN-Dibenzylpyridin-4-amine 3cc Rf (80 ethyl acetate inethanol) 032 1H NMR (200MHz CDCl

3) 120575 467 (s 4H)

658 (dd 119869 = 48 16Hz 2H) 719ndash740 (m 10H) 820


(dd 119869 = 48 16Hz 2H) 13C NMR (50MHz CDCl3) 120575

532 1071 1264 1274 1289 1368 1502 1539

NNndashDi(4-fluorobenzyl)pyridin-4-amine 3ee Rf (80 ethylacetate in dichloromethane) 040 1H NMR (200MHzCDCl

3) 120575 461 (s 4H) 656 (dd 119869 = 50 16Hz 2H)

699ndash719 (m 8H) 822 (dd J = 50 16Hz 2H) 13C NMR(50MHz CDCl

3) 120575 525 1071 1158 (d 119869 = 216Hz) 1281

(d 119869 = 80Hz) 1323 (d 119869 = 32Hz) 1503 1536 1622(d 119869 = 2458Hz)

NN-Di(4-trifluoromethylbenzyl)pyridin-4-amine 3ff Rf(80 ethyl acetate in dichloromethane) 025 1H NMR(200MHz CDCl

3) 120575 473 (s 4H) 658 (dd 119869 = 50 16Hz

2H) 736ndash759 (m 8H) 826 (dd J = 50 16Hz 2H) 13CNMR (50MHz CDCl

3) 120575 531 1071 1233 (q 119869 = 37Hz)

1238 (q 119869 = 2723Hz) 1245 (q 119869 = 38Hz) 1297 1314(q 119869 = 324Hz) 1377 1504 1534

56 Biological Assays

561 Antifungal Assay

Organisms For the antifungal evaluation strains obtainedfrom the American Type Culture Collection (ATCC Rock-ville MD USA) the German Collection of Microorganisms(DSMZ Braunschweig Germany) and the PharmaceuticalMicrobiology Culture Collection (PMC Department ofPublic Health and Infectious Diseases ldquoSapienzardquo UniversityRome Italy) were tested The strains were Candida albicans(ATCC 10231 ATCC 10261 ATCC 24433 ATCC 900283153 PMC 1002 PMC 1011 and PMC 1030) C parapsilosisATCC22019 C parapsilosis DSM 11224 C tropicalis DSM11953 C tropicalis PMC 0908 C tropicalis PMC 0910 Cglabrata PMC 0805 C krusei DSM 6128 and C kruseiPMC 0613 Cryptococcus neoformans (DSM 11959 PMC2102 PMC 2107 PMC 2111 and PMC 2136) dermatophytes(Trichophyton mentagrophytes DSM 4870 T mentagrophytesPMC6509 Microsporum gypseum DSM 7303 and Mgypseum PMC 7331) All of the strains were stored andgrown in accordance with the procedures of the Clinical andLaboratory Standards Institute (CLSI) [26 27]

Antifungal Susceptibility Assays In vitro antifungal suscep-tibility was evaluated using the CLSI broth microdilutionmethods [26 27] Fluconazole and Amphotericin B wereused as reference drugs The final concentration rangedfrom 0125 to 64 120583gmL The compounds were dissolvedpreviously in DMSO at concentrations 100 times higherthan the highest desired test concentration and successivelydiluted in test medium in accordance with the proceduresof the CLSI [28] Microdilution trays containing 100 120583L ofserial twofold dilutions of compounds in RPMI 1640medium(Sigma-Aldrich St Louis MO USA) were inoculated withan organism suspension adjusted to attain a final inoculumconcentration of 10 times 103ndash15 times 103 cellsmL for yeasts and04 times 10

4ndash5 times 104 CFUmL for dermatophytes The panelswere incubated at 35∘C and observed for the presence of

growth at 48 h (Candida spp) and 72 h (C neoformans anddermatophytes)

The minimal inhibitory concentration (MIC) was foryeasts the lowest concentration that showed ge 50 growthinhibition compared with the growth control and for der-matophytes the lowest concentration that showed ge 80growth inhibition compared with the growth control TheMIC100

was the lowest drug concentration that prevented100 of growth with respect to the untreated controlAccording to CSI protocols the fluconazole MIC

50and the

amphotericin B MIC100

were calculated (2223) The resultswere expressed as the geometric mean (GM) of the MICvalues

562 Antiprotozoal Assay For the evaluation of antiproto-zoal and cytotoxic activity an integrated panel of microbialscreens and standard screening methodologies were adoptedas previously described [29] on the following organismschloroquine-resistant P falciparum K 1-strain L infantumMHOMMA (BE)67 amastigote stage suramin-sensitiveTrypanosoma brucei Squib-427 strain Trypanosoma cruziTulahuen CL2 (benznidazole-sensitive) strain human fetallung fibroblast cells (MRC-5 SV2)

All assays were performed in triplicate Compounds weretested at 5 concentrations (64 16 4 1 and 025120583gmL)to establish a full dose titration and determine the IC

50

(inhibitory concentration 50) The final in-test concentra-tion of DMSO did not exceed 05 which is known not tointerfere with the different assays [29]

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

This work was financially supported by Miur Italy Theauthors thank Mr Marco Di Pilato for his support in theexperimental part of the work

References

[1] G R Luedtke K Schinzel X Tan et al ldquoAmide-basedinhibitors of p38120572 MAP kinase Part 1 Discovery of novelN-pyridyl amide lead moleculesrdquo Bioorganic and MedicinalChemistry Letters vol 20 no 8 pp 2556ndash2559 2010

[2] M Otsuka M Fujita Y Sugiura et al ldquoSynthetic inhibitors ofregulatory proteins involved in the signaling pathway of thereplication of human immunodeficiency virus 1rdquo Bioorganicand Medicinal Chemistry vol 5 no 1 pp 205ndash215 1997

[3] H Nishida Y Miyazaki T Mukaihira et al ldquoSynthesis andevaluation of 1-arylsulfonyl-3-piperazinone derivatives as afactor Xa inhibitor II Substituent effect on biological activitiesrdquoChemical and Pharmaceutical Bulletin vol 50 no 9 pp 1187ndash1194 2002

[4] C A Willoughby K G Rosauer J J Hale et al ldquo134Trisubstituted pyrrolidine CCR5 receptor antagonists bearing


4-aminoheterocycle substituted piperidine side chainsrdquo Bioor-ganic andMedicinal Chemistry Letters vol 13 no 3 pp 427ndash4312003

[5] D de Vita L Scipione S Tortorella et al ldquoSynthesis andantifungal activity of a new series of 2-(1H-imidazol-1-yl)-1-phenylethanol derivativesrdquo European Journal of MedicinalChemistry vol 49 pp 334ndash342 2012

[6] L Friggeri L Scipione R Costi et al ldquoNew promising com-pounds with in vitro nanomolar activity against TrypanosomaCruzirdquoMedicinal Chemistry Letters vol 4 pp 538ndash541 2013

[7] C K Chen P S Doyle L V Yermalitskaya et al ldquoTrypanosomaCruzi CYP51 inhibitor derived from a Mycobacterium tubercu-losis screen hitrdquo PLoS Neglected Tropical Diseases vol 3 no 2article e372 2009

[8] T Y Hargrove Z Wawrzak P W Alexander et al ldquoCom-plexes of Trypanosoma Cruzi Sterol 14120572-Demethylase (CYP51)with two pyridine-based drug candidates for chagas diseasestructural basis for pathogen selectivityrdquo Journal of BiologicalChemistry vol 288 pp 31602ndash31615 2013

[9] Q Xu Q Li X Zhu and J Chen ldquoGreen and scalable aldehyde-catalyzed transition metal-freeDehydrative N-Alkylation ofamides and amines with alcoholsrdquo Advanced Synthesis andCatalysis vol 355 pp 73ndash80 2013

[10] Q Li S Fan Q Sun H Tian X Yu and Q Xu ldquoCopper-catalyzed N-alkylation of amides and amines with alcoholsemploying the aerobic relay race methodologyrdquo Organic andBiomolecular Chemistry vol 10 no 15 pp 2966ndash2972 2012

[11] A Martınez-Asencio D J Ramon and M Yus ldquoN-Alkylationof poor nucleophilic amines and derivatives with alcohols by ahydrogen autotransfer process catalyzed by copper(II) acetatescope andmechanistic considerationsrdquo Tetrahedron vol 67 no17 pp 3140ndash3149 2011

[12] R Martınez D J Ramon and M Yus ldquoSelective N-monoalkylation of aromatic amines with benzylic alcoholsby a hydrogen autotransfer process catalyzed by unmodifiedmagnetiterdquo Organic and Biomolecular Chemistry vol 7 no 10pp 2176ndash2181 2009

[13] E J Delaney L E Wood and I M Klotz ldquoPoly(ethylenimines)with alternative (alkylamino)pyridines as nucleophilic cata-lystsrdquo Journal of the American Chemical Society vol 104 no 3pp 799ndash807 1982

[14] T Zhao and G Sun ldquoSynthesis and characterization of antimi-crobial cationic surfactants aminopyridinium saltsrdquo Journal ofSurfactants and Detergents vol 9 no 4 pp 325ndash330 2006

[15] T Ito T Ikemoto Y Isogami et al ldquoPractical synthesis of low-density lipoprotein receptor upregulator N-[1-(3-phenylpro-pane-1-yl)piperidin-4-yl]-5-thia-18b-diazaacenaphthylene-4-carboxamiderdquo Organic Process Research and Development vol6 no 3 pp 238ndash241 2002

[16] O M Singh S J Singh N K Su and S-G Lee ldquoReaction oflithioamines with alkyl halides a convenient direct synthesisof N-alkylaminopyridinesrdquo Bulletin of the Korean ChemicalSociety vol 28 no 1 pp 115ndash117 2007

[17] D M Krein and T L Lowary ldquoA convenient synthesis of 2-(alkylamino)pyridinesrdquo Journal of Organic Chemistry vol 67no 14 pp 4965ndash4967 2002

[18] The direct cathodic reduction of N-Boc-4AP led to its depro-tection and to the formation of 4AP

[19] L Rossi M Feroci and A Inesi ldquoThe electrogeneratedcyanomethyl anion in organic synthesisrdquo Mini-Reviews inOrganic Chemistry vol 2 no 1 pp 79ndash90 2005

[20] M Feroci D de Vita L Scipione G Sotgiu and S Tor-torella ldquoElectrogenerated acetonitrile anion induced selectiveN-alkylation of bifunctional compoundsrdquo Tetrahedron Lettersvol 53 no 20 pp 2564ndash2567 2012

[21] M Feroci I Chiarotto L Rossi and A Inesi ldquoActivationof elemental sulfur by electrogenerated cyanomethyl anionsynthesis of substituted 2-aminothiophenes by the Gewaldreactionrdquo Advanced Synthesis and Catalysis vol 350 no 17 pp2740ndash2746 2008

[22] M Feroci ldquoSynthesis of 120573-lactams by 4-exo-tet cyclizationprocess induced by electrogenerated cyanomethyl anion part 2Stereochemical implicationsrdquoAdvanced Synthesis and Catalysisvol 349 no 13 pp 2177ndash2181 2007

[23] M Feroci M A Casadei M Orsini L Palombi and A InesildquoCyanomethyl anioncarbon dioxide system an electrogener-ated carboxylating reagent Synthesis of carbamates under mildand safe conditionsrdquo Journal of Organic Chemistry vol 68 no4 pp 1548ndash1551 2003

[24] M Feroci M Orsini G Sotgiu L Rossi and A Inesi ldquoElec-trochemically promoted C-N bond formation from acetylenicamines and CO

2 Synthesis of 5-methylene-13-oxazolidin-2-

onesrdquo Journal of Organic Chemistry vol 70 no 19 pp 7795ndash7798 2005

[25] Y Basel and A Hassner ldquoDi-tert-butyl dicarbonate and4-(dimethylamino)pyridine revisited Their reactions withamines and alcoholsrdquo Journal of Organic Chemistry vol 65 no20 pp 6368ndash6380 2000

[26] CLSI Reference Method for Broth Dilution Antifungal Suscep-tibility Testing of Yeasts Approved Standard 3rd edition CLSIDocument M27A3 Clinical and Laboratory Standards InstituteWayne Pa USA 2008

[27] CLSI Reference Method for Broth Dilution Antifungal Sus-ceptibility Testing of Filamentous Fungi Approved Standard2nd edition CLSI Document M38-A2 Clinical and LaboratoryStandards Institute Wayne Pa USA 2008

[28] CLSI Reference Method for Broth Dilution Antifungal Suscep-tibility Testing of Yeasts 3rd inFormational Supplement CLSIDocumentM27-S3 Clinical and Laboratory Standards InstituteWayne Pa USA 2008

[29] P Cos A J Vlietinck D V Berghe and LMaes ldquoAnti-infectivepotential of natural products how to develop a stronger in vitrorsquoproof-of-conceptrsquordquo Journal of Ethnopharmacology vol 106 no3 pp 290ndash302 2006

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy



Analytical ChemistryVolume 2014

Journal of


Quantum Chemistry


Organic Chemistry International


CatalystsJournal of

ElectrochemistryInternational Journal of



NN Slow FastH2N H2N +

Xminus

RndashNH NndashRRndashX RndashX

Scheme 1 Reaction of 4-aminopyridine with alkyl halides

[16] obtaining N-methyl- and N-ethyl-4-aminopyridines in74ndash80 yields

A viable alternative is the enhancement of the nucle-ophilicity of the amine nitrogen atom (versus the pyridineone) allowing the use of weaker bases An example is theactivation of 2-aminopyridine as formyl or Boc derivativeat the amine nitrogen atom [17] with subsequent deproto-nation using sodium hydride alkylation and deprotectionwith trifluoroacetic acid The deprotonation of N-Boc-2-aminopyridine with NaH needs a careful control of thetemperature (0ndash5∘C) and is carried out in anhydrous DMFwith a vigorous stirring required to keep the suspension fluid

In this context we envisaged the possibility to alkylateN-Boc-4-aminopyridine (N-Boc-4AP) usingmilder reactionconditions that is using electrogenerated tetraethylammo-nium cyanomethanide (Et4N+minusCH

2CN) [18] This base the

acetonitrile anion can be easily obtained by cathodic gal-vanostatic reduction of a solution of acetonitrile contain-ing tetraethylammonium hexafluorophosphate as supportingelectrolyte (Scheme 2) without by-products (the reagent isthe electron) and it was successfully used by us in a goodvariety of reactions [19] such as the selective N-alkylationof bifunctional compounds [20] the Gewald reaction [21]the synthesis of 120573-lactams [22] and the synthesis of car-bamates [23] The actual mechanism for the formation ofacetonitrile anion is not known but a hypothesis based onthe direct reduction of the tetraethylammonium cation hasbeen reported (Scheme 2) [24]

The high reactivity of this base is ascribable to thelarge tetraethylammonium counterion which renders theacetonitrile anion extremely reactive Moreover its reactionas a base gives no by-products as the protonation restores themolecule of solvent

2 Results and Discussion

The reaction of electrogenerated acetonitrile anion with4AP followed by an alkyl halide leads to poor yields indesired compound with the pyridinium salt being the majorproduct This prevents the direct use of minusCH

2CN with 4AP

On the other hand if the amine nitrogen is activated asBoc derivative (N-Boc-4AP) the deprotonationalkylationreaction using acetonitrile anion leads to products 1 in veryhigh yields (Scheme 3 and Table 1 entries 1ndash6) The classicdeprotection with trifluoroacetic acid allows obtaining thedesired products 2 (Scheme 3 and Table 1 entries 1ndash6)

The data in Table 1 highlight that the reaction of depro-tonation of N-Boc-4AP using electrogenerated acetonitrileanion alkylation with both alkyl and benzyl halides anddeprotection with trifluoroacetic acid is very efficient withoverall yields of 78ndash86 However when the alkylating agentis a bromoacetophenone the yields in alkylated product are

lower and inmost cases the deprotection reaction leads to thedealkylation of the starting material (Table 1 entries 7ndash10)

As many biologically active compounds contain thedialkylated 4-aminopyridine moiety we tried to carry out asecond alkylation on products 2andashj using acetonitrile anionbut as expected the high nucleophilicity of the pyridinenitrogen led to the synthesis of the corresponding pyridiniumsalt

We thus carried out this second alkylation using strongbases the most efficient being t-BuOK in DMSO (Scheme 4)although the yields in dialkylated 4AP were not very highThe results of this reaction are reported in Table 2

In order to obtain symmetrically dialkylated 4AP 4APwas subjected to deprotonation with t-BuOK in DMSOadding an excess of alkylating agent The reaction led toa mixture of mono- and dialkylated 4-aminopyridines inmoderate to acceptable yields The results are reported inTable 3

3 Biological Activity

A selection of synthesized compounds was in vitro testedto evaluate antifungal activity against different strains of Calbicans C parapsilosis and Cryptococcus neoformans dataare reported in Table 4 As can be evidenced the nonsym-metrical dialkylated 4APs 3ac and 3ae showed a moderateantifungal activity towards C albicans and C parapsilosiswith MIC

50values of 32 120583gmL and showed an interesting

activity against Cryptococcus neoformans with MIC50values

of 04 and 4 120583gmL respectively Otherwise the symmetricaldialkylated 4APs 3cc 3ee and the Boc-protected monoalky-lated 4APs 1b 1e 1f showed poor antifungal activity withMIC50and MIC

100ge 64 120583gmL

Furthermore the symmetrical dialkylated 4APs 3cc 3eeand 3ff were in vitro tested to evaluate the activity againstTry-panosoma cruzi Trypanosoma brucei Leishmania infantumand Plasmodium falciparum the results are summarized inTable 5

As can be evidenced all tested compounds showed amoderate activity versus P falciparum and an interestingactivity towards L infantum with IC

50values lower than the

reference drug miltefosine otherwise they resulted scarcelyactive against T cruzi and T brucei Moreover these com-pounds also showed low toxic activity versus growingMRC-5cells

4 Conclusion

In conclusion we demonstrated the usefulness of electro-generated acetonitrile anion in the alkylation of N-Boc 4-aminopyridines both from the point of viewof the high yieldsand of the cleanliness of the reaction (no by-products) Thedeprotection of N-Boc 4-aminopyridines allowed obtainingmonoalkylated 4-aminopyridine in very high yields Thefollowing alkylation by means of t-BuOK and alkyl halidesled to nonsymmetrically dialkylated 4-aminopyridine whilesymmetrically dialkylated products were obtained directlyfrom 4-aminopyridine by reaction with an excess of t-BuOKand alkyl halide




1 Br6N

NBoc

6

1a gt95

N

HN 6

2a 91

2Br

N

NBoc

Ph

1b 85

N

HN Ph

2b 93

3Cl

N

NBoc

1c 85

N

HN

2c gt95

4 Br

Cl

Cl N

NBoc

Cl

Cl

1d 95

N

HN

Cl

Cl

2d 91

5Br

FN

NBoc

F

1e 93

N

HN

F

2e 90

6Br

F3C N

NBoc

CF3

1f 90

N

HN

CF3

2f 87

7

OBr

N

NBoc

O

1g 34N

HNO

2g trb


Table 1 Continued


8

OBr

FN

NBoc

O

F

1h 38

N

HNO

F

2h trb

9

OBr

ClN

NBoc

O

Cl

1i 56

N

HNO

Cl

2i trb

10

OBr

ON

NBoc

O

O

1j 48

N

HNO

O




Et4N∙

Et4N∙

Et∙ + eminus


minusCH2CN

Et3N + Et∙+eminus


N N

NHBoc

N

NBoc R

N

HNR

4AP N-Boc-4AP

NH2

(Boc)2OCH3CN rt

(1)

(2)


1andashj 2andashj



N

HNR

2N

NR

(1) t-BuOK DMSO rt

R998400

3

(2) R998400ndashX






1N

HN

2a

6

Cl

N

N 6

3ac 29

2N

HN

2c

Br6N

N 6

3ac 34

3N

HN

2e

F Br6N

N 6

F

3ae 24

4N

HN

2e

F Br

N

N

F







3) 120575 153 (s9H) 69 (bs 1H) 732 (dd 119869 = 48 16Hz


3) 120575 282 817 1123 1456 1503 1519 EIMS mz 194

(M+ 1) 137 (2) 121 (5) 120 (8) 94 (50) 78 (4) 57(100)







3as internal

standard




1Br

N

N

3bb 36

2Cl

N

N

3cc 42

3Br

F N

N

F F

3ee 39

4Br

F3C N

N

CF3

3ff 65

F3C









L infcIC50 120583M

Pf-K1dIC50 120583M

MRC-5IC50 120583M








3) 120575 088 (t 119869 = 65Hz 3H) 120ndash130 (m 10H)


3) 120575 140 226 267 282 284 291

317 487 814 1188 1500 1501 1534


3) 120575 148 (s 9H) 186ndash202 (m 2H) 264


3) 120575 282 300 330 483 816 1189 1261 1283 1285

1410 1497 1503 1534 EIMSmz M+ absent 212 (5) 107(100) 105 (5) 91 (25) 78 (27) 77 (12)


3) 120575 145 (s 9H) 494 (s 2H) 720ndash737 (m 7H) 846


525 821 1182 1263 1273 1287 1377 1502 1501 1535EIMS mz M+ absent 227 (4) 183 (14) 91 (100) 78(7) 57 (51)


3) 120575 148 (s 9H) 529 (s 2H) 702ndash721


3) 120575 282 467 817 1215 1286 1295 1317 1361 1481

1499 1533 EIMSmz 352 (M+ 1) 252 (3) 163 (6) 161(30) 159 (42) 78 (76) 51 (100)


3) 120575 145 (s 9H) 489 (s 2H) 697ndash722


3) 120575 281 518 822 1166 (d 119869 = 215Hz) 1184 1281



3) 120575 146 (s 9H) 499 (s 2H) 720ndash736 (m


3) 120575 281 522 825 1181



3) 120575 146 (s 9H) 509 (s 2H) 726


3) 120575 281

555 825 1187 1279 1289 1339 1347 1502 1532 1937


3) 120575 146 (s 9H) 505 (s


3) 120575 281 554 826

1162 (d 119869 = 220Hz) 1188 1306 (d 119869 = 94Hz) 1311(d 119869 = 32Hz) 1501 1502 1532 1662 (d 119869 = 2561Hz)1922


3) 120575 145 (s 9H) 504 (s 2H) 721


3) 120575 281 554 826 1188 1293 1330 1405

1499 1503 1531 1927


3) 120575 146 (s 9H) 390 (s 3H) 504


3) 120575 281 551 555 823 1141 1187

1278 1302 1502 1533 1641 1920



3COOH





3) 120575 089 (t 119869 =


3) 120575 141 226 270 288 292 292 318 429 1074 1552


3CN) 120575 191ndash206 (m 2H) 271


3CN) 120575 298 325 420 1073 1259 1283 1284

1410 1415 1578 EIMS mz 212 (M+ 1) 107 (100) 91(43) 78 (13)


3) 120575 446 (d 119869 = 60Hz 2H) 67 (bs


3) 120575 468 1074 1272 1276 1288 1377 1486

1540 EIMS mz 184 (M+ 15) 183 (15) 107 (5) 91(100) 78 (16)


3CN) 120575459 (s 2H) 60 (bs 1H)


3CN) 120575 422

1074 1287 1304 1328 1360 1473 1546 EIMS mz 256(M+ + 4 1) 254 (M+ + 2 7) 252 (M+ 14) 162 (10)160 (67) 158 (100) 78 (37)


3) 120575 438 (d J = 54Hz 2H)


3) 120575 463 1078 1158



3) 120575 451 (d 119869 =


3) 120575 454 1078 1244 (q 119869 = 2710Hz) 1254 (q 119869 =

39Hz) 1284 (q J = 319Hz) 1277 1432 1467 1550 EIMSmz 252 (M+ 80) 183 (11) 159 (100) 107 (52) 78(31)


3) 120575 390 (s 3H) 457 (d 119869 = 38Hz 2H) 46 (bs


3) 120575 482 556 1081 1141 1272 1302 1508

1536 1645 1916


2



3) 120575 086ndash092


3) 120575 141 226 269 270 292 294

297 318 507 534 1069 1262 1273 1288 1368 1489 1536


3) 120575 086ndash092


3) 120575 141 192 226 269 292 293 317

513 533 1074 1161 (d 119869 = 217Hz) 1279 (d J = 81Hz)1309 (d 119869 = 35Hz) 1449 1553 1623 (d 119869 = 2465Hz)


3) 120575 191ndash203 (m 2H) 268 (t 119869 =


3) 120575 281 330 499 529 1068 1158

(d 119869 = 216Hz) 1263 1279 (d 119869 = 80Hz) 1283 12861321 (d 119869 = 32Hz) 1407 1479 1537 1621 (d J =2458Hz)


2




1407 1524


3) 120575 467 (s 4H)

658 (dd 119869 = 48 16Hz 2H) 719ndash740 (m 10H) 820



532 1071 1264 1274 1289 1368 1502 1539


3) 120575 461 (s 4H) 656 (dd 119869 = 50 16Hz 2H)


3) 120575 525 1071 1158 (d 119869 = 216Hz) 1281

(d 119869 = 80Hz) 1323 (d 119869 = 32Hz) 1503 1536 1622(d 119869 = 2458Hz)


3) 120575 473 (s 4H) 658 (dd 119869 = 50 16Hz


3) 120575 531 1071 1233 (q 119869 = 37Hz)

1238 (q 119869 = 2723Hz) 1245 (q 119869 = 38Hz) 1297 1314(q 119869 = 324Hz) 1377 1504 1534









50and the





50




Acknowledgments


References











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of






1 Br6N

NBoc

6

1a gt95

N

HN 6

2a 91

2Br

N

NBoc

Ph

1b 85

N

HN Ph

2b 93

3Cl

N

NBoc

1c 85

N

HN

2c gt95

4 Br

Cl

Cl N

NBoc

Cl

Cl

1d 95

N

HN

Cl

Cl

2d 91

5Br

FN

NBoc

F

1e 93

N

HN

F

2e 90

6Br

F3C N

NBoc

CF3

1f 90

N

HN

CF3

2f 87

7

OBr

N

NBoc

O

1g 34N

HNO

2g trb


Table 1 Continued


8

OBr

FN

NBoc

O

F

1h 38

N

HNO

F

2h trb

9

OBr

ClN

NBoc

O

Cl

1i 56

N

HNO

Cl

2i trb

10

OBr

ON

NBoc

O

O

1j 48

N

HNO

O




Et4N∙

Et4N∙

Et∙ + eminus


minusCH2CN

Et3N + Et∙+eminus


N N

NHBoc

N

NBoc R

N

HNR

4AP N-Boc-4AP

NH2

(Boc)2OCH3CN rt

(1)

(2)


1andashj 2andashj



N

HNR

2N

NR

(1) t-BuOK DMSO rt

R998400

3

(2) R998400ndashX






1N

HN

2a

6

Cl

N

N 6

3ac 29

2N

HN

2c

Br6N

N 6

3ac 34

3N

HN

2e

F Br6N

N 6

F

3ae 24

4N

HN

2e

F Br

N

N

F







3) 120575 153 (s9H) 69 (bs 1H) 732 (dd 119869 = 48 16Hz


3) 120575 282 817 1123 1456 1503 1519 EIMS mz 194

(M+ 1) 137 (2) 121 (5) 120 (8) 94 (50) 78 (4) 57(100)







3as internal

standard




1Br

N

N

3bb 36

2Cl

N

N

3cc 42

3Br

F N

N

F F

3ee 39

4Br

F3C N

N

CF3

3ff 65

F3C









L infcIC50 120583M

Pf-K1dIC50 120583M

MRC-5IC50 120583M








3) 120575 088 (t 119869 = 65Hz 3H) 120ndash130 (m 10H)


3) 120575 140 226 267 282 284 291

317 487 814 1188 1500 1501 1534


3) 120575 148 (s 9H) 186ndash202 (m 2H) 264


3) 120575 282 300 330 483 816 1189 1261 1283 1285

1410 1497 1503 1534 EIMSmz M+ absent 212 (5) 107(100) 105 (5) 91 (25) 78 (27) 77 (12)


3) 120575 145 (s 9H) 494 (s 2H) 720ndash737 (m 7H) 846


525 821 1182 1263 1273 1287 1377 1502 1501 1535EIMS mz M+ absent 227 (4) 183 (14) 91 (100) 78(7) 57 (51)


3) 120575 148 (s 9H) 529 (s 2H) 702ndash721


3) 120575 282 467 817 1215 1286 1295 1317 1361 1481

1499 1533 EIMSmz 352 (M+ 1) 252 (3) 163 (6) 161(30) 159 (42) 78 (76) 51 (100)


3) 120575 145 (s 9H) 489 (s 2H) 697ndash722


3) 120575 281 518 822 1166 (d 119869 = 215Hz) 1184 1281



3) 120575 146 (s 9H) 499 (s 2H) 720ndash736 (m


3) 120575 281 522 825 1181



3) 120575 146 (s 9H) 509 (s 2H) 726


3) 120575 281

555 825 1187 1279 1289 1339 1347 1502 1532 1937


3) 120575 146 (s 9H) 505 (s


3) 120575 281 554 826

1162 (d 119869 = 220Hz) 1188 1306 (d 119869 = 94Hz) 1311(d 119869 = 32Hz) 1501 1502 1532 1662 (d 119869 = 2561Hz)1922


3) 120575 145 (s 9H) 504 (s 2H) 721


3) 120575 281 554 826 1188 1293 1330 1405

1499 1503 1531 1927


3) 120575 146 (s 9H) 390 (s 3H) 504


3) 120575 281 551 555 823 1141 1187

1278 1302 1502 1533 1641 1920



3COOH





3) 120575 089 (t 119869 =


3) 120575 141 226 270 288 292 292 318 429 1074 1552


3CN) 120575 191ndash206 (m 2H) 271


3CN) 120575 298 325 420 1073 1259 1283 1284

1410 1415 1578 EIMS mz 212 (M+ 1) 107 (100) 91(43) 78 (13)


3) 120575 446 (d 119869 = 60Hz 2H) 67 (bs


3) 120575 468 1074 1272 1276 1288 1377 1486

1540 EIMS mz 184 (M+ 15) 183 (15) 107 (5) 91(100) 78 (16)


3CN) 120575459 (s 2H) 60 (bs 1H)


3CN) 120575 422

1074 1287 1304 1328 1360 1473 1546 EIMS mz 256(M+ + 4 1) 254 (M+ + 2 7) 252 (M+ 14) 162 (10)160 (67) 158 (100) 78 (37)


3) 120575 438 (d J = 54Hz 2H)


3) 120575 463 1078 1158



3) 120575 451 (d 119869 =


3) 120575 454 1078 1244 (q 119869 = 2710Hz) 1254 (q 119869 =

39Hz) 1284 (q J = 319Hz) 1277 1432 1467 1550 EIMSmz 252 (M+ 80) 183 (11) 159 (100) 107 (52) 78(31)


3) 120575 390 (s 3H) 457 (d 119869 = 38Hz 2H) 46 (bs


3) 120575 482 556 1081 1141 1272 1302 1508

1536 1645 1916


2



3) 120575 086ndash092


3) 120575 141 226 269 270 292 294

297 318 507 534 1069 1262 1273 1288 1368 1489 1536


3) 120575 086ndash092


3) 120575 141 192 226 269 292 293 317

513 533 1074 1161 (d 119869 = 217Hz) 1279 (d J = 81Hz)1309 (d 119869 = 35Hz) 1449 1553 1623 (d 119869 = 2465Hz)


3) 120575 191ndash203 (m 2H) 268 (t 119869 =


3) 120575 281 330 499 529 1068 1158

(d 119869 = 216Hz) 1263 1279 (d 119869 = 80Hz) 1283 12861321 (d 119869 = 32Hz) 1407 1479 1537 1621 (d J =2458Hz)


2




1407 1524


3) 120575 467 (s 4H)

658 (dd 119869 = 48 16Hz 2H) 719ndash740 (m 10H) 820



532 1071 1264 1274 1289 1368 1502 1539


3) 120575 461 (s 4H) 656 (dd 119869 = 50 16Hz 2H)


3) 120575 525 1071 1158 (d 119869 = 216Hz) 1281

(d 119869 = 80Hz) 1323 (d 119869 = 32Hz) 1503 1536 1622(d 119869 = 2458Hz)


3) 120575 473 (s 4H) 658 (dd 119869 = 50 16Hz


3) 120575 531 1071 1233 (q 119869 = 37Hz)

1238 (q 119869 = 2723Hz) 1245 (q 119869 = 38Hz) 1297 1314(q 119869 = 324Hz) 1377 1504 1534









50and the





50




Acknowledgments


References











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of




Table 1 Continued


8

OBr

FN

NBoc

O

F

1h 38

N

HNO

F

2h trb

9

OBr

ClN

NBoc

O

Cl

1i 56

N

HNO

Cl

2i trb

10

OBr

ON

NBoc

O

O

1j 48

N

HNO

O




Et4N∙

Et4N∙

Et∙ + eminus


minusCH2CN

Et3N + Et∙+eminus


N N

NHBoc

N

NBoc R

N

HNR

4AP N-Boc-4AP

NH2

(Boc)2OCH3CN rt

(1)

(2)


1andashj 2andashj



N

HNR

2N

NR

(1) t-BuOK DMSO rt

R998400

3

(2) R998400ndashX






1N

HN

2a

6

Cl

N

N 6

3ac 29

2N

HN

2c

Br6N

N 6

3ac 34

3N

HN

2e

F Br6N

N 6

F

3ae 24

4N

HN

2e

F Br

N

N

F







3) 120575 153 (s9H) 69 (bs 1H) 732 (dd 119869 = 48 16Hz


3) 120575 282 817 1123 1456 1503 1519 EIMS mz 194

(M+ 1) 137 (2) 121 (5) 120 (8) 94 (50) 78 (4) 57(100)







3as internal

standard




1Br

N

N

3bb 36

2Cl

N

N

3cc 42

3Br

F N

N

F F

3ee 39

4Br

F3C N

N

CF3

3ff 65

F3C









L infcIC50 120583M

Pf-K1dIC50 120583M

MRC-5IC50 120583M








3) 120575 088 (t 119869 = 65Hz 3H) 120ndash130 (m 10H)


3) 120575 140 226 267 282 284 291

317 487 814 1188 1500 1501 1534


3) 120575 148 (s 9H) 186ndash202 (m 2H) 264


3) 120575 282 300 330 483 816 1189 1261 1283 1285

1410 1497 1503 1534 EIMSmz M+ absent 212 (5) 107(100) 105 (5) 91 (25) 78 (27) 77 (12)


3) 120575 145 (s 9H) 494 (s 2H) 720ndash737 (m 7H) 846


525 821 1182 1263 1273 1287 1377 1502 1501 1535EIMS mz M+ absent 227 (4) 183 (14) 91 (100) 78(7) 57 (51)


3) 120575 148 (s 9H) 529 (s 2H) 702ndash721


3) 120575 282 467 817 1215 1286 1295 1317 1361 1481

1499 1533 EIMSmz 352 (M+ 1) 252 (3) 163 (6) 161(30) 159 (42) 78 (76) 51 (100)


3) 120575 145 (s 9H) 489 (s 2H) 697ndash722


3) 120575 281 518 822 1166 (d 119869 = 215Hz) 1184 1281



3) 120575 146 (s 9H) 499 (s 2H) 720ndash736 (m


3) 120575 281 522 825 1181



3) 120575 146 (s 9H) 509 (s 2H) 726


3) 120575 281

555 825 1187 1279 1289 1339 1347 1502 1532 1937


3) 120575 146 (s 9H) 505 (s


3) 120575 281 554 826

1162 (d 119869 = 220Hz) 1188 1306 (d 119869 = 94Hz) 1311(d 119869 = 32Hz) 1501 1502 1532 1662 (d 119869 = 2561Hz)1922


3) 120575 145 (s 9H) 504 (s 2H) 721


3) 120575 281 554 826 1188 1293 1330 1405

1499 1503 1531 1927


3) 120575 146 (s 9H) 390 (s 3H) 504


3) 120575 281 551 555 823 1141 1187

1278 1302 1502 1533 1641 1920



3COOH





3) 120575 089 (t 119869 =


3) 120575 141 226 270 288 292 292 318 429 1074 1552


3CN) 120575 191ndash206 (m 2H) 271


3CN) 120575 298 325 420 1073 1259 1283 1284

1410 1415 1578 EIMS mz 212 (M+ 1) 107 (100) 91(43) 78 (13)


3) 120575 446 (d 119869 = 60Hz 2H) 67 (bs


3) 120575 468 1074 1272 1276 1288 1377 1486

1540 EIMS mz 184 (M+ 15) 183 (15) 107 (5) 91(100) 78 (16)


3CN) 120575459 (s 2H) 60 (bs 1H)


3CN) 120575 422

1074 1287 1304 1328 1360 1473 1546 EIMS mz 256(M+ + 4 1) 254 (M+ + 2 7) 252 (M+ 14) 162 (10)160 (67) 158 (100) 78 (37)


3) 120575 438 (d J = 54Hz 2H)


3) 120575 463 1078 1158



3) 120575 451 (d 119869 =


3) 120575 454 1078 1244 (q 119869 = 2710Hz) 1254 (q 119869 =

39Hz) 1284 (q J = 319Hz) 1277 1432 1467 1550 EIMSmz 252 (M+ 80) 183 (11) 159 (100) 107 (52) 78(31)


3) 120575 390 (s 3H) 457 (d 119869 = 38Hz 2H) 46 (bs


3) 120575 482 556 1081 1141 1272 1302 1508

1536 1645 1916


2



3) 120575 086ndash092


3) 120575 141 226 269 270 292 294

297 318 507 534 1069 1262 1273 1288 1368 1489 1536


3) 120575 086ndash092


3) 120575 141 192 226 269 292 293 317

513 533 1074 1161 (d 119869 = 217Hz) 1279 (d J = 81Hz)1309 (d 119869 = 35Hz) 1449 1553 1623 (d 119869 = 2465Hz)


3) 120575 191ndash203 (m 2H) 268 (t 119869 =


3) 120575 281 330 499 529 1068 1158

(d 119869 = 216Hz) 1263 1279 (d 119869 = 80Hz) 1283 12861321 (d 119869 = 32Hz) 1407 1479 1537 1621 (d J =2458Hz)


2




1407 1524


3) 120575 467 (s 4H)

658 (dd 119869 = 48 16Hz 2H) 719ndash740 (m 10H) 820



532 1071 1264 1274 1289 1368 1502 1539


3) 120575 461 (s 4H) 656 (dd 119869 = 50 16Hz 2H)


3) 120575 525 1071 1158 (d 119869 = 216Hz) 1281

(d 119869 = 80Hz) 1323 (d 119869 = 32Hz) 1503 1536 1622(d 119869 = 2458Hz)


3) 120575 473 (s 4H) 658 (dd 119869 = 50 16Hz


3) 120575 531 1071 1233 (q 119869 = 37Hz)

1238 (q 119869 = 2723Hz) 1245 (q 119869 = 38Hz) 1297 1314(q 119869 = 324Hz) 1377 1504 1534









50and the





50




Acknowledgments


References











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of






1N

HN

2a

6

Cl

N

N 6

3ac 29

2N

HN

2c

Br6N

N 6

3ac 34

3N

HN

2e

F Br6N

N 6

F

3ae 24

4N

HN

2e

F Br

N

N

F







3) 120575 153 (s9H) 69 (bs 1H) 732 (dd 119869 = 48 16Hz


3) 120575 282 817 1123 1456 1503 1519 EIMS mz 194

(M+ 1) 137 (2) 121 (5) 120 (8) 94 (50) 78 (4) 57(100)







3as internal

standard




1Br

N

N

3bb 36

2Cl

N

N

3cc 42

3Br

F N

N

F F

3ee 39

4Br

F3C N

N

CF3

3ff 65

F3C









L infcIC50 120583M

Pf-K1dIC50 120583M

MRC-5IC50 120583M








3) 120575 088 (t 119869 = 65Hz 3H) 120ndash130 (m 10H)


3) 120575 140 226 267 282 284 291

317 487 814 1188 1500 1501 1534


3) 120575 148 (s 9H) 186ndash202 (m 2H) 264


3) 120575 282 300 330 483 816 1189 1261 1283 1285

1410 1497 1503 1534 EIMSmz M+ absent 212 (5) 107(100) 105 (5) 91 (25) 78 (27) 77 (12)


3) 120575 145 (s 9H) 494 (s 2H) 720ndash737 (m 7H) 846


525 821 1182 1263 1273 1287 1377 1502 1501 1535EIMS mz M+ absent 227 (4) 183 (14) 91 (100) 78(7) 57 (51)


3) 120575 148 (s 9H) 529 (s 2H) 702ndash721


3) 120575 282 467 817 1215 1286 1295 1317 1361 1481

1499 1533 EIMSmz 352 (M+ 1) 252 (3) 163 (6) 161(30) 159 (42) 78 (76) 51 (100)


3) 120575 145 (s 9H) 489 (s 2H) 697ndash722


3) 120575 281 518 822 1166 (d 119869 = 215Hz) 1184 1281



3) 120575 146 (s 9H) 499 (s 2H) 720ndash736 (m


3) 120575 281 522 825 1181



3) 120575 146 (s 9H) 509 (s 2H) 726


3) 120575 281

555 825 1187 1279 1289 1339 1347 1502 1532 1937


3) 120575 146 (s 9H) 505 (s


3) 120575 281 554 826

1162 (d 119869 = 220Hz) 1188 1306 (d 119869 = 94Hz) 1311(d 119869 = 32Hz) 1501 1502 1532 1662 (d 119869 = 2561Hz)1922


3) 120575 145 (s 9H) 504 (s 2H) 721


3) 120575 281 554 826 1188 1293 1330 1405

1499 1503 1531 1927


3) 120575 146 (s 9H) 390 (s 3H) 504


3) 120575 281 551 555 823 1141 1187

1278 1302 1502 1533 1641 1920



3COOH





3) 120575 089 (t 119869 =


3) 120575 141 226 270 288 292 292 318 429 1074 1552


3CN) 120575 191ndash206 (m 2H) 271


3CN) 120575 298 325 420 1073 1259 1283 1284

1410 1415 1578 EIMS mz 212 (M+ 1) 107 (100) 91(43) 78 (13)


3) 120575 446 (d 119869 = 60Hz 2H) 67 (bs


3) 120575 468 1074 1272 1276 1288 1377 1486

1540 EIMS mz 184 (M+ 15) 183 (15) 107 (5) 91(100) 78 (16)


3CN) 120575459 (s 2H) 60 (bs 1H)


3CN) 120575 422

1074 1287 1304 1328 1360 1473 1546 EIMS mz 256(M+ + 4 1) 254 (M+ + 2 7) 252 (M+ 14) 162 (10)160 (67) 158 (100) 78 (37)


3) 120575 438 (d J = 54Hz 2H)


3) 120575 463 1078 1158



3) 120575 451 (d 119869 =


3) 120575 454 1078 1244 (q 119869 = 2710Hz) 1254 (q 119869 =

39Hz) 1284 (q J = 319Hz) 1277 1432 1467 1550 EIMSmz 252 (M+ 80) 183 (11) 159 (100) 107 (52) 78(31)


3) 120575 390 (s 3H) 457 (d 119869 = 38Hz 2H) 46 (bs


3) 120575 482 556 1081 1141 1272 1302 1508

1536 1645 1916


2



3) 120575 086ndash092


3) 120575 141 226 269 270 292 294

297 318 507 534 1069 1262 1273 1288 1368 1489 1536


3) 120575 086ndash092


3) 120575 141 192 226 269 292 293 317

513 533 1074 1161 (d 119869 = 217Hz) 1279 (d J = 81Hz)1309 (d 119869 = 35Hz) 1449 1553 1623 (d 119869 = 2465Hz)


3) 120575 191ndash203 (m 2H) 268 (t 119869 =


3) 120575 281 330 499 529 1068 1158

(d 119869 = 216Hz) 1263 1279 (d 119869 = 80Hz) 1283 12861321 (d 119869 = 32Hz) 1407 1479 1537 1621 (d J =2458Hz)


2




1407 1524


3) 120575 467 (s 4H)

658 (dd 119869 = 48 16Hz 2H) 719ndash740 (m 10H) 820



532 1071 1264 1274 1289 1368 1502 1539


3) 120575 461 (s 4H) 656 (dd 119869 = 50 16Hz 2H)


3) 120575 525 1071 1158 (d 119869 = 216Hz) 1281

(d 119869 = 80Hz) 1323 (d 119869 = 32Hz) 1503 1536 1622(d 119869 = 2458Hz)


3) 120575 473 (s 4H) 658 (dd 119869 = 50 16Hz


3) 120575 531 1071 1233 (q 119869 = 37Hz)

1238 (q 119869 = 2723Hz) 1245 (q 119869 = 38Hz) 1297 1314(q 119869 = 324Hz) 1377 1504 1534









50and the





50




Acknowledgments


References











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of






1Br

N

N

3bb 36

2Cl

N

N

3cc 42

3Br

F N

N

F F

3ee 39

4Br

F3C N

N

CF3

3ff 65

F3C









L infcIC50 120583M

Pf-K1dIC50 120583M

MRC-5IC50 120583M








3) 120575 088 (t 119869 = 65Hz 3H) 120ndash130 (m 10H)


3) 120575 140 226 267 282 284 291

317 487 814 1188 1500 1501 1534


3) 120575 148 (s 9H) 186ndash202 (m 2H) 264


3) 120575 282 300 330 483 816 1189 1261 1283 1285

1410 1497 1503 1534 EIMSmz M+ absent 212 (5) 107(100) 105 (5) 91 (25) 78 (27) 77 (12)


3) 120575 145 (s 9H) 494 (s 2H) 720ndash737 (m 7H) 846


525 821 1182 1263 1273 1287 1377 1502 1501 1535EIMS mz M+ absent 227 (4) 183 (14) 91 (100) 78(7) 57 (51)


3) 120575 148 (s 9H) 529 (s 2H) 702ndash721


3) 120575 282 467 817 1215 1286 1295 1317 1361 1481

1499 1533 EIMSmz 352 (M+ 1) 252 (3) 163 (6) 161(30) 159 (42) 78 (76) 51 (100)


3) 120575 145 (s 9H) 489 (s 2H) 697ndash722


3) 120575 281 518 822 1166 (d 119869 = 215Hz) 1184 1281



3) 120575 146 (s 9H) 499 (s 2H) 720ndash736 (m


3) 120575 281 522 825 1181



3) 120575 146 (s 9H) 509 (s 2H) 726


3) 120575 281

555 825 1187 1279 1289 1339 1347 1502 1532 1937


3) 120575 146 (s 9H) 505 (s


3) 120575 281 554 826

1162 (d 119869 = 220Hz) 1188 1306 (d 119869 = 94Hz) 1311(d 119869 = 32Hz) 1501 1502 1532 1662 (d 119869 = 2561Hz)1922


3) 120575 145 (s 9H) 504 (s 2H) 721


3) 120575 281 554 826 1188 1293 1330 1405

1499 1503 1531 1927


3) 120575 146 (s 9H) 390 (s 3H) 504


3) 120575 281 551 555 823 1141 1187

1278 1302 1502 1533 1641 1920



3COOH





3) 120575 089 (t 119869 =


3) 120575 141 226 270 288 292 292 318 429 1074 1552


3CN) 120575 191ndash206 (m 2H) 271


3CN) 120575 298 325 420 1073 1259 1283 1284

1410 1415 1578 EIMS mz 212 (M+ 1) 107 (100) 91(43) 78 (13)


3) 120575 446 (d 119869 = 60Hz 2H) 67 (bs


3) 120575 468 1074 1272 1276 1288 1377 1486

1540 EIMS mz 184 (M+ 15) 183 (15) 107 (5) 91(100) 78 (16)


3CN) 120575459 (s 2H) 60 (bs 1H)


3CN) 120575 422

1074 1287 1304 1328 1360 1473 1546 EIMS mz 256(M+ + 4 1) 254 (M+ + 2 7) 252 (M+ 14) 162 (10)160 (67) 158 (100) 78 (37)


3) 120575 438 (d J = 54Hz 2H)


3) 120575 463 1078 1158



3) 120575 451 (d 119869 =


3) 120575 454 1078 1244 (q 119869 = 2710Hz) 1254 (q 119869 =

39Hz) 1284 (q J = 319Hz) 1277 1432 1467 1550 EIMSmz 252 (M+ 80) 183 (11) 159 (100) 107 (52) 78(31)


3) 120575 390 (s 3H) 457 (d 119869 = 38Hz 2H) 46 (bs


3) 120575 482 556 1081 1141 1272 1302 1508

1536 1645 1916


2



3) 120575 086ndash092


3) 120575 141 226 269 270 292 294

297 318 507 534 1069 1262 1273 1288 1368 1489 1536


3) 120575 086ndash092


3) 120575 141 192 226 269 292 293 317

513 533 1074 1161 (d 119869 = 217Hz) 1279 (d J = 81Hz)1309 (d 119869 = 35Hz) 1449 1553 1623 (d 119869 = 2465Hz)


3) 120575 191ndash203 (m 2H) 268 (t 119869 =


3) 120575 281 330 499 529 1068 1158

(d 119869 = 216Hz) 1263 1279 (d 119869 = 80Hz) 1283 12861321 (d 119869 = 32Hz) 1407 1479 1537 1621 (d J =2458Hz)


2




1407 1524


3) 120575 467 (s 4H)

658 (dd 119869 = 48 16Hz 2H) 719ndash740 (m 10H) 820



532 1071 1264 1274 1289 1368 1502 1539


3) 120575 461 (s 4H) 656 (dd 119869 = 50 16Hz 2H)


3) 120575 525 1071 1158 (d 119869 = 216Hz) 1281

(d 119869 = 80Hz) 1323 (d 119869 = 32Hz) 1503 1536 1622(d 119869 = 2458Hz)


3) 120575 473 (s 4H) 658 (dd 119869 = 50 16Hz


3) 120575 531 1071 1233 (q 119869 = 37Hz)

1238 (q 119869 = 2723Hz) 1245 (q 119869 = 38Hz) 1297 1314(q 119869 = 324Hz) 1377 1504 1534









50and the





50




Acknowledgments


References











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of







L infcIC50 120583M

Pf-K1dIC50 120583M

MRC-5IC50 120583M








3) 120575 088 (t 119869 = 65Hz 3H) 120ndash130 (m 10H)


3) 120575 140 226 267 282 284 291

317 487 814 1188 1500 1501 1534


3) 120575 148 (s 9H) 186ndash202 (m 2H) 264


3) 120575 282 300 330 483 816 1189 1261 1283 1285

1410 1497 1503 1534 EIMSmz M+ absent 212 (5) 107(100) 105 (5) 91 (25) 78 (27) 77 (12)


3) 120575 145 (s 9H) 494 (s 2H) 720ndash737 (m 7H) 846


525 821 1182 1263 1273 1287 1377 1502 1501 1535EIMS mz M+ absent 227 (4) 183 (14) 91 (100) 78(7) 57 (51)


3) 120575 148 (s 9H) 529 (s 2H) 702ndash721


3) 120575 282 467 817 1215 1286 1295 1317 1361 1481

1499 1533 EIMSmz 352 (M+ 1) 252 (3) 163 (6) 161(30) 159 (42) 78 (76) 51 (100)


3) 120575 145 (s 9H) 489 (s 2H) 697ndash722


3) 120575 281 518 822 1166 (d 119869 = 215Hz) 1184 1281



3) 120575 146 (s 9H) 499 (s 2H) 720ndash736 (m


3) 120575 281 522 825 1181



3) 120575 146 (s 9H) 509 (s 2H) 726


3) 120575 281

555 825 1187 1279 1289 1339 1347 1502 1532 1937


3) 120575 146 (s 9H) 505 (s


3) 120575 281 554 826

1162 (d 119869 = 220Hz) 1188 1306 (d 119869 = 94Hz) 1311(d 119869 = 32Hz) 1501 1502 1532 1662 (d 119869 = 2561Hz)1922


3) 120575 145 (s 9H) 504 (s 2H) 721


3) 120575 281 554 826 1188 1293 1330 1405

1499 1503 1531 1927


3) 120575 146 (s 9H) 390 (s 3H) 504


3) 120575 281 551 555 823 1141 1187

1278 1302 1502 1533 1641 1920



3COOH





3) 120575 089 (t 119869 =


3) 120575 141 226 270 288 292 292 318 429 1074 1552


3CN) 120575 191ndash206 (m 2H) 271


3CN) 120575 298 325 420 1073 1259 1283 1284

1410 1415 1578 EIMS mz 212 (M+ 1) 107 (100) 91(43) 78 (13)


3) 120575 446 (d 119869 = 60Hz 2H) 67 (bs


3) 120575 468 1074 1272 1276 1288 1377 1486

1540 EIMS mz 184 (M+ 15) 183 (15) 107 (5) 91(100) 78 (16)


3CN) 120575459 (s 2H) 60 (bs 1H)


3CN) 120575 422

1074 1287 1304 1328 1360 1473 1546 EIMS mz 256(M+ + 4 1) 254 (M+ + 2 7) 252 (M+ 14) 162 (10)160 (67) 158 (100) 78 (37)


3) 120575 438 (d J = 54Hz 2H)


3) 120575 463 1078 1158



3) 120575 451 (d 119869 =


3) 120575 454 1078 1244 (q 119869 = 2710Hz) 1254 (q 119869 =

39Hz) 1284 (q J = 319Hz) 1277 1432 1467 1550 EIMSmz 252 (M+ 80) 183 (11) 159 (100) 107 (52) 78(31)


3) 120575 390 (s 3H) 457 (d 119869 = 38Hz 2H) 46 (bs


3) 120575 482 556 1081 1141 1272 1302 1508

1536 1645 1916


2



3) 120575 086ndash092


3) 120575 141 226 269 270 292 294

297 318 507 534 1069 1262 1273 1288 1368 1489 1536


3) 120575 086ndash092


3) 120575 141 192 226 269 292 293 317

513 533 1074 1161 (d 119869 = 217Hz) 1279 (d J = 81Hz)1309 (d 119869 = 35Hz) 1449 1553 1623 (d 119869 = 2465Hz)


3) 120575 191ndash203 (m 2H) 268 (t 119869 =


3) 120575 281 330 499 529 1068 1158

(d 119869 = 216Hz) 1263 1279 (d 119869 = 80Hz) 1283 12861321 (d 119869 = 32Hz) 1407 1479 1537 1621 (d J =2458Hz)


2




1407 1524


3) 120575 467 (s 4H)

658 (dd 119869 = 48 16Hz 2H) 719ndash740 (m 10H) 820



532 1071 1264 1274 1289 1368 1502 1539


3) 120575 461 (s 4H) 656 (dd 119869 = 50 16Hz 2H)


3) 120575 525 1071 1158 (d 119869 = 216Hz) 1281

(d 119869 = 80Hz) 1323 (d 119869 = 32Hz) 1503 1536 1622(d 119869 = 2458Hz)


3) 120575 473 (s 4H) 658 (dd 119869 = 50 16Hz


3) 120575 531 1071 1233 (q 119869 = 37Hz)

1238 (q 119869 = 2723Hz) 1245 (q 119869 = 38Hz) 1297 1314(q 119869 = 324Hz) 1377 1504 1534









50and the





50




Acknowledgments


References











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of






3) 120575 089 (t 119869 =


3) 120575 141 226 270 288 292 292 318 429 1074 1552


3CN) 120575 191ndash206 (m 2H) 271


3CN) 120575 298 325 420 1073 1259 1283 1284

1410 1415 1578 EIMS mz 212 (M+ 1) 107 (100) 91(43) 78 (13)


3) 120575 446 (d 119869 = 60Hz 2H) 67 (bs


3) 120575 468 1074 1272 1276 1288 1377 1486

1540 EIMS mz 184 (M+ 15) 183 (15) 107 (5) 91(100) 78 (16)


3CN) 120575459 (s 2H) 60 (bs 1H)


3CN) 120575 422

1074 1287 1304 1328 1360 1473 1546 EIMS mz 256(M+ + 4 1) 254 (M+ + 2 7) 252 (M+ 14) 162 (10)160 (67) 158 (100) 78 (37)


3) 120575 438 (d J = 54Hz 2H)


3) 120575 463 1078 1158



3) 120575 451 (d 119869 =


3) 120575 454 1078 1244 (q 119869 = 2710Hz) 1254 (q 119869 =

39Hz) 1284 (q J = 319Hz) 1277 1432 1467 1550 EIMSmz 252 (M+ 80) 183 (11) 159 (100) 107 (52) 78(31)


3) 120575 390 (s 3H) 457 (d 119869 = 38Hz 2H) 46 (bs


3) 120575 482 556 1081 1141 1272 1302 1508

1536 1645 1916


2



3) 120575 086ndash092


3) 120575 141 226 269 270 292 294

297 318 507 534 1069 1262 1273 1288 1368 1489 1536


3) 120575 086ndash092


3) 120575 141 192 226 269 292 293 317

513 533 1074 1161 (d 119869 = 217Hz) 1279 (d J = 81Hz)1309 (d 119869 = 35Hz) 1449 1553 1623 (d 119869 = 2465Hz)


3) 120575 191ndash203 (m 2H) 268 (t 119869 =


3) 120575 281 330 499 529 1068 1158

(d 119869 = 216Hz) 1263 1279 (d 119869 = 80Hz) 1283 12861321 (d 119869 = 32Hz) 1407 1479 1537 1621 (d J =2458Hz)


2




1407 1524


3) 120575 467 (s 4H)

658 (dd 119869 = 48 16Hz 2H) 719ndash740 (m 10H) 820



532 1071 1264 1274 1289 1368 1502 1539


3) 120575 461 (s 4H) 656 (dd 119869 = 50 16Hz 2H)


3) 120575 525 1071 1158 (d 119869 = 216Hz) 1281

(d 119869 = 80Hz) 1323 (d 119869 = 32Hz) 1503 1536 1622(d 119869 = 2458Hz)


3) 120575 473 (s 4H) 658 (dd 119869 = 50 16Hz


3) 120575 531 1071 1233 (q 119869 = 37Hz)

1238 (q 119869 = 2723Hz) 1245 (q 119869 = 38Hz) 1297 1314(q 119869 = 324Hz) 1377 1504 1534









50and the





50




Acknowledgments


References











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of





532 1071 1264 1274 1289 1368 1502 1539


3) 120575 461 (s 4H) 656 (dd 119869 = 50 16Hz 2H)


3) 120575 525 1071 1158 (d 119869 = 216Hz) 1281

(d 119869 = 80Hz) 1323 (d 119869 = 32Hz) 1503 1536 1622(d 119869 = 2458Hz)


3) 120575 473 (s 4H) 658 (dd 119869 = 50 16Hz


3) 120575 531 1071 1233 (q 119869 = 37Hz)

1238 (q 119869 = 2723Hz) 1245 (q 119869 = 38Hz) 1297 1314(q 119869 = 324Hz) 1377 1504 1534









50and the





50




Acknowledgments


References











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of









































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of












Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of



Documents

Efficient Electrochemical N -Alkylation of N -Boc-Protected 4-Aminopyridines: Towards New Biologically Active Compounds