Cyclization of 1-thiocarbamoyl-2-phenylpyrazolidines

Thiocarbamoyl derivatives of N-phenylpyrazolidines are converted under the influence of acidic agents to mixtures of tetrahydropyrimido[2,1-b]benzothiazoles and 2-imino-3-aminoalkylbenzothiazoles and not only to tetrahydropyrimidobenzothiazoles, as previously assumed. The conditions for the predominant formation of tetrahydropyrimidobenzothiazoles were found. Deceased. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 228–233, February, 1980.