412 RECORD OF SCIENCE FOR 1886. 



Synthesis of Conine, by A, Ladenburg. — Conine, the volatile alkaloid 

 which forms the poisonous principle of hemlock (conium maculatum), 

 was discovered in 1827 by Giesecke, but was first obtained in a pure 

 state in 1831 by Geiger. It has been often studied by chemists, nota- 

 bly by Ortigosa, Blyth, Wertheim, and Kekule and von Planta; the 

 two latter gave it the formula CsHiglS", but it is now known to be CgHnN. 

 It forms a colorless, oily liquid of pungent odor, specific gravity = 0.89 ; 

 boiling point 166° to 168°. It is easily soluble in alcohol and ether, 

 sparingly in water, and forms crystalline deliquescent salts. It is an 

 active poison. This natural alkaloid has been formed synthetically by 

 Ladenburgin the manner to be described. Hugo Schiff", in 1871, thought 

 he had effected this synthesis by the action of alcoholic ammonia on 

 normal butyric aldehyde and subjecting the i)roduct to dry distillation, 

 but the base thus obtained proved to be paraconine, an isomeric form. 



Ladenburg's researches on the pyridine bases had already yielded 

 him interesting results. The synthesis of piperidine was noted in our 

 report for the year 1884. On the 25th of February he read a paper be- 

 fore the German Chemical Society entitled ".Experiments on the Syn- 

 thesis of Conine," in which he announced the preparation of a base 

 very closely resembling this alkaloid, and in October be presented de- 

 tails of this remarkably interesting synthesis, and proofs of the iden- 

 tity of the artificial and natural .substances. The process is as follows : 

 Paraldehyde and rt-picoline are heated for ten hours iu closed tubes 

 to a temperature of 250"^ to 260°. The allylpyridine thus obtained was 

 separated from the unchanged picoline, purified and fractioned until it 

 distilled at 187°.5 to 192^.5. The exact nature of this body was care- 

 fully established by many tests. The a allylpyridine was then sub- 

 mitted in alcoholic solution to the reducing action of sodium, whereby 

 ar-propylpiperidine was obtained. The hydrochloride of this base, 

 when purified, melted at 203° to 205°, and crystallized in silky- white 

 needles. 



The base separated from this salt boiled at 16G<=* to 167° and i)roved 

 to have the greatest resemblance to conine. After a very careful study 

 of its toxic and optical properties the author satisfied himself of the 

 absolute identity of this dextro — «'-propylpiperidine and conine, 

 C3H7. CjHio. HN. (Ber. d. chem. Ges., xix, 439 and 2578.) 



Ifew Synthesis of mi Inactive Borneol, by J. Bouchardat and J. La- 

 font. — Berthelot accomplished the synthesis of the camphor of Borneo 

 by treating camphor with potassium alcoholate, and Baubigny by the 

 direct addition of hydrogen. The authors effect the transformation of 

 terebene, or inactive camphene, CmHie, through the medium of an organic 

 acid into an ether of borneol, which by saponification yields a borneol 

 having no influence on polarized light. With the exception of its in- 

 active optical properties, the new body is identical with borneol. 

 (Oomptes Eendus, cii, 171.) 



