N

NN

O

CO2Me

CO2Me

SL205 (K4, CMLD005040)2.0 µM - core dimerization

OMe

N

NN

O

CO2Me

CO2Me

SL204 (I4, CMLD005019)IC50 = 3.7 µM

O

N

NN

O

CO2Me

CO2Me

SL203 (B4/N4, CMLD005037/CMLD005092)

9.9 µM - core dimerization

CF3

N

NN

O

CO2Me

CO2Me

SL206 (M4, CMLD005075)IC50 = 4.7 µM

N

NN

O

CO2MeCO2Me

OMe

NN

N

HN

O

N

N

NN

OOMe

CO2Me

CO2Me

N NN

N

N

NN

OOMe

CO2Me

CO2Me

N N

Me

MeO

N

N

NN

O Ph

CO2Me

CO2Me

N NN

N

N

NN

O Ph

CO2Me

CO2Me

N N

Me

MeO

N

NN

OOMe

CO2Me

CO2Me

N

N NHO

Synthesis of Small Molecule Inhibitors Against Hepatitis C May Young, Mark Busch, Kyle Strom, John K. Snyder

Boston University, Chemistry Department Hepatitis C, the leading cause of liver disease, affects over 170 million people worldwide.1,2 The hepatitis C virus (HCV) encodes 10 viral proteins for infection and propagation and of the 10 HCV proteins, core, the nucleocapsid protein, presents a unique therapeutic target, as core is responsible for the assembly of new viral particles for viral proliferation through core dimerization and is the most conserved.2,3 The synthesis of small molecule inhibitors against core dimerization, which initiates viral assembly, is reported. Core dimerization inhibitors synthesized through inverse electron demand Diels-Alder chemistry by the intramolecular cycloaddition of tryptophan derivatives with tethered 1,2,4-triazines were shown to be active against the HCV proliferation, and, hence, subsequent efforts were focused on tethering a second heterocycle to the parent adduct tetracyclic core structure for preparation of a second generation library. Diversification of these compounds has been achieved through a copper catalyzed azide-alkyne cycloaddition reaction, which will be screened against hepatitis C for antiviral activity.

•  Screen small libraries for core dimerization inhibitors •  Identification of several compounds that exhibit biological

activity against Hepatitis C

N

NN

MeO2CMeO

Me

O

CO2Me

CO2Me

SL 201 (N6, CMLD 003452)IC50 5.7 µM - core dimerization

(validated by resynthesis)

•  Preparation of a second-generation library, using SL 201 as a structural lead

•  Inverse electron demand Diels-Alder chemistry by the intramolecular cycloaddition of tryptophan derivatives with tethered 1,2,4-triazines 2

•  Tethering a second heterocycle to the parent adduct tetracyclic core structure to bind to a secondary pocket on the protein surface and enhance the inhibition of proton-proton interactions

•  Several compounds designed by tethering an azide to the tetracyclic core for subsequent modification using click chemistry

Background

Synthesis Scheme

NH

i) NaH (1.5 eq), THF, rt, 30 min

ii) (1.6 eq), 50 °C, 14 h

Br Br N

Br

CO2Me CO2Me

MeOH, H2SO4

reflux, 3 hNH

COOH i) LiOH (5 eq), THF/H2O, rt, 4 hii) (COCl)2 (2.6 eq), DMF (cat.), CH2Cl2, rt, 1 h

iii) Triazine (1.6 eq), TEA (2.4 eq), DMAP (cat.), CH2Cl2, rt, 3 h

N

Br

NN

N

CO2MeCO2Me

HNOMe

Triazine

ON

N NN

OMe

MeO2CCO2Me

N

Br

ON

N NN

OMe

MeO2CCO2Me

PhCl, reflux, 12 h

N

Br

NN

OOMe

CO2Me

CO2Me

N

N3

NN

OOMe

CO2Me

CO2MeNaN3 (1.2 eq), DMF,

50 °C, 10 h

Click Chemistry

N

N3

NN

OOMe

CO2Me

CO2Me

N

NN

OOMe

CO2Me

CO2Me

R

N

NNR

(+)-Sodium L-ascorbate,CuSO4

1:1:1tBuOH:H2O:CH2Cl2

80 °C, 30 min

NHAc

OHN

OMe

•  Click reactions – reactions that can be accomplished very simply •  Used to build second heterocycle onto the parent core •  Performed an azide-alkyne cycloaddition with a copper catalyst

using a variety of substituents to build a small library wherein the structure of second heterocyclic ring varies

Future Work

Works Cited

1.  Wei, W.; Cai, C.; Kota, S.; Takahashi, V.; Ni, F.; Strosberg, A.D.; Snyder, J.K. New Small Molecule Inhibitors of Hepatitis C Virus. Bioorganic & Medicinal Chemistry Letters. 2009, 19, 6926 – 6930.

2.  Ni, F.; Kota, S.; Takahashi, V.; Strosberg, A.D.; Snyder, J.K. Potent Inhibitors of Hepatitis C Core Dimerization as New Leads for Anti-Hepatitis C Agents. Bioorganic & Medicinal Chemistry Lett. 2011, 2198 – 2202.

3.  Kota, S.; Takahashi, V.; Ni, F.; Snyder, J.K.; Strosberg, A. D. Direct Binding of a Hepatitis C Virus Inhibitor to the Viral Capsid Protein. PLoS ONE. 2012, 7, e32207.

4.  Benson, S.C.; Gross, J.L.; Snyder, J.K. Indole as a Dienophile in Inverse Electron Demand Diels-Alder Reactions: Reactions with 1,2,4-Triazines and 1,2-Diazines. J. Org. Chem.1990, 55, 3257-3269.

Acknowledgements

Dr. John K. Snyder Kyle Strom Mark Busch

Boston University CIC Boston University CMLD

•  Reduce original 6 membered D-ring to a 5 membered ring •  Yield lower molecular weight with high molecular weight being

a major drawback for previous molecules

N

NN

O

CO2Me

CO2Me

SL209 (A5, CMLD005699)IC50: 1.4 µM - core dimerization

EC50: 3.2 µM - viral replication inhibiton(validated by resynthesis)

N

NN

O

CO2Me

CO2Me

SL210 (N3, CMLD005084)2.0 µM - core dimerization

OMe

OMe

OMe

N

N

CH3

N

O

CO2Me

CO2Me

SL207 (F5, CMLD005012)11.5 µM - core dimerization

OCH3

N

N

CH3

N

O

CO2Me

CO2Me

SL208 (F5, CMLD005006)4.0 µM - core dimerization

O

O

Second Generation Library Attachment of a Second Heterocycle

N

NN

O

CO2Me

CO2Me

O

NN

N

O

CO2MeCO2Me

N

NN

O

CO2Me

CO2Me

NN

N

O

CO2MeCO2Me

( )n SL235: n =1, IC50 1.9 µM, CC50 <36 µMMW = 930; cLogP = 10.5

SL236: n = 2, IC50 1.0 µM, CC50 <36 µMMW = 958; cLogP = 10.1

SL231IC50 = 98 nM

CC50 <100 µMMW = 960

cLogP = 10.2

N

NN

O

COOMe

COOMe

N NN

OMe

SL250IC50 92 nMMW = 653cLogP = 4.4

N

NN

O

COOMe

COOMe

N NN

NHO

SL251IC50 341 nMMW = 702cLogP = 7.9

Diversification