Ethylpyridine ester

The Cannizzaro reaction of heterocyclic aldehydes has been examined in a few cases only. Furfural,83 a-thiophenealdehyde,84 and a-pyridylal-dehyde 86 undergo the reaction normally to give the expected products. 3-Formyl-l,2,5,6-tetrahydro-l-ethylpyridine resinifies upon treatment with potassium hydroxide,86 a behavior consistent with the observation that it is structurally similar to an a,/3-unsaturated alicyclic aldehyde. 3,4-Dibromothiophene-2,5-dialdehyde undergoes a complex series of reactions, involving both cleavage (loss of —CHO) and dismutation, when treated with alkali.87 Of particular interest in this connection is the fact that under certain conditions the ester composed of the usual... 

At 140° in methanol, a much more extensive decomposition of akuammicine occurs, and the products isolated are 3-ethylpyridine and 2-hydroxycarbazole (XXXV). The formation of 3-ethylpyridine is presumably the result of a normal Hofmann degradation of the pyri-dinium ester corresponding to XXXIII the other product should consequently have been methyl 3-vinyl-2-indolylacetate (XXXIV), but this was not obtained. It was accordingly suggested that the 2-hydroxycarbazole obtained was formed from XXXIV by intramolecular nucleophilic attack of the vinylogous enamine methylene group on the carbomethoxy group (arrows in XXXIV), followed by elimination of methanol and aromatization (39). 

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