A. G. Mikhailovskii, D. Korchagin, O. V. Gashkova
Oct 22, 2016
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Influential Citations
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Journal
Russian Journal of Organic Chemistry
Abstract
Abstract“Push–pull” enamines of the 1,2,3,4-tetrahydroisoquinoline series, 2-(3,3-dimethyl-1,2,3,4-tetrahydroisoquinolin- 1-ylidene)acetamides, reacted as 1,3-binucleophiles with ninhydrin to form tricyclic tetrahydroindeno[1,2-b]pyrrole system. The nucleophilic centers in the enamines were the amide NH2 group and ß-carbon atom of the enamine fragment. The reaction of ninhydrin with 2-[2,2-dimethyl-2,3-dihydrobenzo[f]-isoquinolin-1(4H)-ylidene]-1-(pyrrolidin-1-yl)ethanone involved only addition to the ß-carbon atom of the enamine fragment. The different reaction directions were rationalized by steric effect of two methyl groups in position 3 of the isoquinoline ring. The Knoevenagel condensation product was obtained by the reaction of ninhydrin with drotaverine (base). The structure of the 1,3-addition product, (3aS,8bS,Z)-{2,2-dimethyl-2,3- dihydrobenzo[f]isoquinolin-4(1H)-ylidene}-3a,8b-dihydroxy-1,3,3a,8b-tetrahydroindeno[1,2-b]pyrrole-2,4-dione, was confirmed by X-ray analysis.