XXXV.—The action of ethyl chloroformate on pyridine and quinoline

Thomas Hopkins
1920 Journal of the Chemical Society Transactions  
COMPARATIVELY few experiments appear to have been carried out on the action of halogen derivatives of the simplelr aliphatic esters or the somewhat closely related compounds, the acid chlorides, on pyridine and quinoline. The first investigations were t-hose of Gerichten (Ber., 1882, 15, 1251) and Kruger (Ber., 1890, 23, 2608), who obtained pyridine-betaine hydrochloride by the inbradion of chloroacetic acid and pyridine. It was found that at 202-205O, pyridine-beltaine hydrochloride decomposes
more » ... into pyridine, methyl chloride, and carbon dioxide. Below this temperature, hokever, pyridine-betaine appears to be quite stable. Rhoussopoulos (Ber., 1882, 15, 2006) treated quinoslinel with ethyl chloroacetate, and obtained the chloridel of quinoline-betaine ethyl ester. Dennstedt and Zimmermann (Ber., 1886, 19, 75) studied the interaction of pyridine and acetyl chloride,. They found that an additive1 product was first formed, and, on heating oved the water-bath, the first4 products isolate\d welre pyridine and dehydracetic acid. The latter is formeld from the acetyl chloride, and the pyridine is regarded as acting by removing the elements of hydrogen chloride. The final products of them reactions are colourless substances. With ethyl chloroformate, pyridine forr-is a dolourless, additive c o m p o z~~d , which rapidly changes t o red. Thei additive compounds of pyridine with hydrogen chloride, methyl chloride, or benzyl chloride are all colourless substances. It does not appear possible! t o put forward any structural elxplanation of the intense colour of the compound formed from ethyl chloroformate and pyridine without recoursel t o the hypotshesis of partial valency. As at present such an hypothesis doee not admit of expelrimentlal verification, the cause of the colour has not been satisfactorily elucidated. The compound of quinolinet and ethyl chlorof ormate is canary-yellow and is only stable a t very low temperatnres.
doi:10.1039/ct9201700278 fatcat:sca7thmuf5gyjccwxpb3rxz4pa