THE ALKALOIDS OF CORYDALlS CAVA-CORYBULBINE. 23

III.-Y7ie ,;llkccloi'cls of Corydalis cava-Co~*ybulbi.izc.. By JAMES J. DOBEIE, &LA., D.Sc., and ALEXANDER LACDER.

IN a paper which appeared in the Berichte (25, Zhll), Messrs. Preund and Josephi mentioned that they had obtained from the crude Cory- daline supplied to them by Schuchardt, of Gorlitz, a small quantity of an a.lkalo'id melting a t 205--207", and soluble in caustic alkali. We supposed this alkalo'id to be identical with that which we subsequently described under the name corytnberine (Trans., 1893, 63, CSS), but we find from 2 more recent paper by the same authors (Annulen, 277, I), that the alkalo'id referred to by them was quite distinct from corytuberine, which was therefore isolated as well as described for the first time by us.

The quantity of material which Preund and Josephi had at their disposal was insnfficient for more than a slight examination of the properties of the new alkalo'id, to which they gave the name of corybulbine, and they have, therefore, left the fuller investigation of it in our hands.

Corybulbine is obtained from Schuchardt's crude corydaline by the following method. After the corydaline has been thoroughly ex-

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26 DOBBIE AND LAUDER: THE ALKALOIDS

hausted with boiling water to remove the corytuberine, the residue, which consists of corydaliiie mixed with a small quantity of Cory- bulbine, is repeatedly exhausted with hotl alcohol, which easily removes the corydaline. The crude corybulbine is then dissolved in a large quantity of boiling alcohol, from which it separates, on cool- ing, i n the form of a fine crystalline deposit, leaving the remainder of the corydaline in solution. The corybulbine obtained in this way is collected, dried, and dissolved in hot dilute hydrochloric acid. The acid solution, on cooling, deposits the hydrochloride, which, after re- crystallisation, is dissolved in boiling water with the aid of a little hydrochloric acid, and the corybulbine, precipitated from this solution by the addition of ammonia, is finally crystallised from alcohol. This method of preparation affords an excellent means of separa>ting corybulbine from the last traces of corydaline, the hydrochloride of which is milch more easily soluble in water than that of the new alkaloiid .

Corybulbine may also be prepared from the crude material, after freeing it from corytuberine, by dissolving it in hydrochloric acid, and precipitating the corydaline with excess of a solution of sodium hydroxide ; the filtrate from the corydnline, when saturated with carbon dioxide, deposits the coi-ybulbine.

Corybulbine is soluble in boiling alcohol, fi=om which i t separates, on cooling, as a fine crystalline powder. It is practically insoluble in water, and nearly so in ether; i t is sparingly soluble in boiling methylic alcohol. readily in carbon bisulphid e, chloroform, and hot benzene. It is distinguished from corydaline and corytuberine, as well as from the bases described by Freund and Joseplii (AiznaEen, 277, 1 ) by its greater insolubility in alcohol. An alcoholic solution of the alkaloid rapidly reduces a solution of silver nitrate when heated with it. Corybulbine begins to soften at 210", but does not melt till heated to 238-240". Freund and Josephi state that the alkalo'id softens a t about 200°, and decomposes at 20$--208", but they some- times found the melting point some degrees higher. A solution of the alkaloid in chloroform is dextrorotatory.

W e have not succeeded 8s yet in obtaining crystals of corybulbine sufficiently large to allow of our describing their form. All the specimens we hare examined have been pale-yellow, but me are nnable to state positively whether or not the colour is a property of the substance, or is a u e to slight decomposition, as in the case of corydaline.

The following are the results of the ana lp is of the alkalo'id, purified by repeated recrystallisation f r o m alcohol, and dried a t 100".

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O F CORYDALIS CAVA-GORTBULBINE. 27

I. 0.2167 gave 0.1382 H,O. H = '7.08. 11. 0-2683 ,, 0.7023 GO, and 0.1'732 H,O. C = 71.38 ; H = 7.17.

111. 0.2214 ,, 0.5788 GO, and 0.1516 H,O. C = 71.29 : H = 7.60. 1V. 0.3211 ,, 0.0891 Pt. N = 4.00 per cent. V. 0.2993 ,, 0.0849 Pt. N = 4.09 ., Mean of the above analyses :-C = 71.33 ; H = 7-28 ; N = 4.04

per cent. These numbers lead to the formula C21H25N04, which requires C = 70.99, H = 7.04, N = 3.94 per cent.

Corybulbine forms easily crystdlisable salts with hydrochloric acid and sulphuric acid.

Co!rybzdbine Hydrochloride.-This salt is prepared by dissolving the alkalo'id in hot hydrochloric acid, from which i t separates, on cooling, in clusters of thick, prismatic crystals. It requires a large quantity of boiling water for solution, bu t this is greatly facilitated by the addition of a little hydrochloric acid. The salt contains no water of crystallisation. It was dried at loo", and a complete analysis of it made, to serve as a check on the analysis of the alkaloid.

I. 0.2432 gave 0.5756 GO, and 0.1536 H,O. C = 64.55 ; H = 7.01. 11. 0.2880 ,, 0.9736 Ptl. N = 3.68 per cent. III. 0.2891 ,, 0.1071 AgCI. C1 = 9.15 ,, IV. 0.2679 ,, 0.1011 AgC1. C1 = 9.33 ,, V. 0.2052 ,, 0.0769 AgC1. Cl = 9-26 ,, C21H2JN04,HC1 requires C = 64.36 ; H = 6.64; N = 3.57 ; Cl =

The addition of a solution of potassium iodide to a solution of the hydrochloride in water, produces a pale yellow precipitate of the hydriodide, which is insoluble in cold, but readily soluble in hot water. ,

Corybulbine XuZplzute.-The acid sulphate is obtained by dissolving the alkalo'id in hot dilute sulphuric acid. When the solution is allowed to cool slowly, long, prismatic, colourless crystals separate ; it contains no water of crystallisation. It is somewhat more easily soluble in hot water than the hydrochloride. It was dried at lOG", and gave the following results on analysis.

S = 6*$8. 11. 0.3494 ,, 0.1775 BaS04. S = 6.98.

9.07 per cent.

I. 0.3517 gave 0.1763 BaSO4.

C21H26RT04,HzS04 requires S = 7-06 per cent.

C'orybzdbiize PEatinoc7zEo~irie.-The platinochloride is obtained by adding a solution of hydrogen plntinochloride to a solution of corg- bulbine hydrochloride in water. It is a pale yellow substance slightly soluble in water. It was dried at loo", and gare the following results on analysis.

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28 DOBBIE AND LAUDER: TEE ALKALOIDS

T. 0.2578 gave 0.0441 Pt. Pt = 17.10. 11. 0,3257 ,, 0.0560 Pt. Pt = 17.19.

111. 0.4445 ,, 0.0771 Pt. Pt = 17.34. These analyses were made on different preparations of the salt ;

mean Pt = 17.21 per cent. (C,1H,5N04)2,H2PtC16 requires Pt = 17.41 per cent.

When a solution of gold chloride is added to a solution of Cory- bulbine hydrochloride in watei-, a flocculent, orange-coloured precipi- t a te is obtained, b?nt as this salt is readily decomposed we did not attempt t o analyse it.

Corybzdbine Meilliodide.-This compound is prepared by digesting -the nlkalo'id with a mixture of absolute alcohol and rnethylic iodide, for several hours, in a flask having a reflux condenser attached to it. On evaporating the solution, the methiodide crystallises out i n clusters of large, yellow, prismatic crystals, which were purified by recrystallisation from alcohol. After being dried a t loo", the iodine was determined with the following results.

I. 0.2862 gave 0.1327 &I. I = 25.05. 11. 0.2590 ,, 0.1214 AgI. I = 25-35.

C21H,5N04*CH31: requires 25-55 per cent. I. Action of H y d y o g e n Iodide o n CorybuZbine.-When corybulbine is

treated with a concentrated solution of hydrogen iodide (sp. gr. 1*7), methylic iodide distils over, and a yellow, crgstalline compound sepa- rates from the liquid remaining in the flask. The methoxy-groups were determined by Zeisel's method with the following result.

I. 0.2091 gave 0,4032 AgI ; 25.46 per cent. OCH,. Three methoxy-groups in C21H25N04 require OCH, = 26.19 per cent. Corybulbine is the fifth alkaloid which has now been separated

from the tubers of Co?-yduZis cam.

Bulbocapnine, C,,H,,NO,. Corycavin, C2,Hz3N05. Corydaline, C,,H,,N04. Corytu berine, C,,HZ5NO4. Corybulbine, C21Hz5N01.

In addition to the alkalo'ids here enumerated, an amorphous sub- stance of low melting point (65-73") is mentioned by Freund and Josephi as having been obtained by Merck from the roots of CoryduZis cuz;u, but as it is doubtful whether it is homogeneous, we have omitted it from our list. In their first paper on the alkalo'ids of CorydaZis cmu, Freund and

Josephi gave the formnla C,H36N,0, for bulbocapnine (Ber., 25,2412), but they have since altered it to C,,H,,NO,. Although several of the

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30 SCHUNCK : THE YELLOW COLOURING MATTER

alkaloids mentioned above approach each other very closely in com- position, they are easily distinguished by their reactions and by their behaviour when treated with hydrogen iodide. Thus, corytuberine alone is soluble in warm water : corybul bin, bulbocapnine, and Cory- taberine are all soluble in sodium hydroxide, whilst corj-daline and corycavine are insoluble in both these solvents. The two last men- tioned alkalo'ids are distinguished from one another by the much greater solubility of the former in alcohol. Although there is n larger number of oxygen atoms in corycavine than in any other of these alkalo'ids, i t does not contain any methoxy-groups. Of the remaining alkalo'ids, dl of which contain four oxygen atoms, bulbocapnine has one, corytuberine two, corybulbine three, and corydaline four meth- oxy-groups. I n a note t o their paper in the A~maleiz, Freund and Josephi suggest tha t corytuberine may be identical with the Cory- dalinnobiline obtained by Birsmann from Corydnlis rzobilis (Imm!]. Disser., Dorpat, 1892). A careful comparison of our results with those of Birsmann does not bear out this suggestion, the analysis, as well as the properties of the substance described by him, differing considerably from those of corytuberine ; as, however, the quantity of material which Birsmann had at his disposal was insuficient for n thorough examination of his alkaloid, it is impossible to institute a perfectly satisfactory cornparison between the t w o substances. If Birsmann really had corytuberine in hand, he could hardly have over- looked the powerful fluorescence of its aqueous solution,

We subjoin a, synopsis of some of the properties of those alkalo'ids of Corydalis c a ~ a which hai-e been most carefully examined.

Umhersity College of AFoq*tlz Wales, Ba?LgOY.

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