A Facile Synthesis of Oxoindenothiazine and Dioxospiro(indene-2,4′-thiazine) Derivatives from (Substituted ethylidene)hydrazinecarbothioamides.

( E)-2-[2-(1-Substituted ethylidene)hydrazinyl]-5-oxo-9b-hydroxy-5,9b-dihydroindeno[1,2- d][1,3]-thiazine-4-carbonitriles and ( E)-5-oxo-[( E)-(1-substituted ethylidene)hydrazinyl]-2,5-dihydroindeno[1,2- d][1,3]thiazine-4-carbonitriles have been obtained from the reaction of 2-(substituted ethylidene)hydrazinecarbothioamides with 2-(1,3-dioxo-2,3-dihydro-1 H-inden-2-ylidene)propanedinitrile ( 1) in ethyl acetate solution. However, ( Z)-6′-amino-1,3-dioxo-3′-substituted-2′-[( E)-(1-phenylethylidene)hydrazono]-1,2′,3,3′-tetrahydrospiro(indene-2,4′-[1,3]thiazine)-5′-carbonitriles were observed during the reaction of N-substituted-2-(1-phenylethylidene)hydrazinecarbothioamides with ( 1). The structure assignment of products has been confirmed on the basis of 1H-, 13C-NMR, and , as well as theoretical calculations. [ABSTRACT FROM AUTHOR]