O. I. Kharaneko, S. L. Bogza
Mar 1, 2013
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0
Influential Citations
7
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Journal
Chemistry of Heterocyclic Compounds
Abstract
Pyrrolo[3,4-d][1,2]diazepines are heterocyclic analogs of the 2,3-benzodiazepine structure, but remain rare and little studied to this time. Their synthesis consists of the stepwise addition of a tosylmethylisocyanide dianion to 1,2-diazepines and has been reported only once [1]. At the same time, the interest in these compounds is linked to the search for convenient methods of synthesis for heterocyclic analogs of tofisopam [2] and talampanel [3], and to broadening of the range of lead compounds for design of medicinal compounds. The aim of our work was the development of a simple method for preparing pyrrolo[3,4-d][1,2]diazepines by the cyclization of pyrrole polycarbonyl compounds using hydrazine. We developed a novel general method for the preparation of the 5,7-dihydropyrrolo[3,4-d][1,2]diazepin-1(2H)-ones 3a,b by recylization of the pyrano[3,4-c]pyrrol-4(2H)-ones 2a,b using hydrazine. The pyrano[3,4-c]pyrrol-4(2H)-ones 2a,b were formed in quantitative yields by fusing the pyrroles 1a,b in the presence of catalytic amounts of toluenesulfonic acid. Pyrroles 1a,b were obtained by an addition reaction with simultaneous cyclization using acetoacetate enamines and dibenzoylethylene [4].