HOWARD AND HODGKIN ON A

XI. -On a New Alkaloid f r o m Cinchom Bark.

By DAVID HOWARD and JOHN HODGBIN.

JN investigating the alkalo'ids yielded by the singular bark described by Dr. Bliickiger as C7zi1i.a Cuprea, we have met with an alkalo'id which appears peculiar to this species, and is quite distinet from that which M. Arnaud has described (Compt. rend., 93, 593) under the name of cinchonamine, which he has obtained from the same species of bark.

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NEW ALKALOID FROM CINCHOSA BARK. 67

The characteristics of this bark are very remarkable ; the extreme hardness and density of the tissue distinguish it from that of all other cinchonas, and it is not surprising to find that it yields fresh alkaloids.

It was first imported in l S i 1 , and was examined by Dr. Fluckiger, and by him named, as above menhioned, China Cup~ea. Within. the last few months it has been seni over in immense quantities from Buccarramanga, in the province of Santander, where it is said to form whole forests, all other species of cinchona being found in their native forests in small clumps or isolated trees.

It varies greatly in valne, some specimens yielding no quinine, while others give upwards of 2 per cent. ; there is also found in most samples a small percentage of quinidine and cinchonine, but we have not yet found cinclionidine present.

The new alkaloid, which we have been for some time investigating, presents a singular analogy to quinine in its properties, aud the analysis of the platinum salt points to a composition identical with or closely resembling that of quinine.

The specific rotary power also is very near that of quinine, from which it differs in the solubility of its salts, and the readiness with which it crystallises from ether. We would therefore suggest the name of H o m o q u i n i n e , following the nomenclature adopted by Dr. Hesse, who has distinguished as homocinchonidine an alkalo'id closely resembling cinchonidine in its general charaoteristics and action on polarised light, but differing slightly in the solubility and appear- ance of its salts.

The alkaloid which we are describing is but moderately soluble in ether, 100 C.C. of ether free from alcohol dissolving only 0.57 a t 12" ; it is more soluble in ether containing alcohol ; when 8 per cent. of the latter is present 100 C.C. dissolves 2.27. Alcohol of 90 per cent. a t 1%' dissolves 7.64 per 100 C.C.

When impure and mixed with other alkalo'ids it is much more soluble, and it is very apt to show supersaturation to a great extent.

The subhate resembles that of quinine in appearance, buh crystal- lises in shorter needles; it appears to contain 6 mols. of water, but effloresces so readily that the exact hydration is difficult t o determine. It is but slightly soluble in water, 1 part of the salt requiring upwards of 100 parts of water a t 100" for solution. On cooling the solution crystallises, leaving 0.25 per 100 C.C. in solution. A slight excess ot' :lcid greatly increases the solubility, and the bisulphate is extremely soluble, and crystallises with difficulty in long needles.

The neutra2 sulphnte is scarcely soluble in strong spirit, but is some- what more soluble in spirit of 50 per cent. than in water.

The oxaZate is very like that of quinine, and dissolves with difficulty j n boiling water, from which i t crystallises on. cooling.

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cis BRAUNER : CONTRIEUTIONS TO THE

The tartrate is but very slightly soluble in water, and closely resembles the tartrates of quinine and cinchonidine. The hydrochloride and nitrate are very soluble, and separate, on cooling or evaporation of a,

strong solution, as oily layers. The hydriodide closely resembles that of quinine. On cooling a hot saturated solution of the alkalo'id in spirit there is a similar separation of the alkalo'id as an oily substance ; from less concentrated solutions it crystallises in small needle-shaped crystals .

The platinum salt contains water of crystallisation, which is lost at 140". On incineration of the anhydrous salt it gives 26.74 per cent. Pt ; the corresponding salt of quinine gives 26.73 per cent'.

W e have not found the alkalo'id to give Dalleiochine with chlorine and ammonia.

The solutions of the sulphate in excess of acid are fluorescent. The iodosnlphate is more soluble than that of quinine, but does not

crystallise so readily. The alkalo'id and its salts give a left-handed rotation to the polarised

ray, nearly approaching that of quinine. The alkaloi'd in a 5 per cent. solution in spirit of 90 per cent. shows a rotation of -156".

The sulphate in a 5 per cent. solution in water containing 0.5 per cent. H2S04 shows a rotation of -209" for the anhydrous salt, with 1 per cent. of acid preswt in excess, of 220". Further investigations on larger quantities of this interesting body are required to dekraiixie all its relations, but in the meantime the results given above seemed to us of sufficient importauce to bring before the Society.

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