Sara M. Mostafa

Formation of dioxospiroindene[1,3]thiazine and thioxoindeno[2,1- d ]imidazolone derivatives from alkenylidene-hydrazinecarbothioamides

The reaction of (substituted) alkenylidene-hydrazinecarbothioamides with 2-(1,3-dioxo-2,3-dihydro-1H-inden-2-ylidene)propanedinitrile led to the formation of 1,3-dioxospiroindene[1,3]-thiazine and thioxoindeno[2,1-d]imidazolone derivatives in modest yields. In addition, 1,3-dihydroxyindan-2-ylidenepropanedinitrile was found. Explanations of these conversions involving nucleophilic reactions and condensations are presented.

Synthesis of spiro(indenepyrazole) and indenotriazinone derivatives from 4-substituted thiosemicarbazides and (1,3-dioxo-2,3-dihydro-1 H -inden-2-ylidene)propanedinitrile

In a multistep reaction, N-substituted-5′-amino-4′-cyano-1,3-dioxo-1,3-dihydro-spiro[indene-2,3′-pyrazole]-2′(1H) carbothioamides (63–71 %) and 4-substituted-3-thioxo-3H-indeno[1,2-e][1,2,4] triazin-9(4H)-ones (17–26 %) have been formed, from a series of 4-substituted thiosemicarbazides 1a–f with (1,3-dioxo-2,3-dihydro-1H-inden-2-ylidene)propanedinitrile 3 in aerated ethyl acetate. Rationales of these conversions involving the nucleophilic reactions and condensation are presented.

Heterocyclisation of substituted ylidenethiocarbonohydrazides using dimethyl acetylenedicarboxylate

A facile and rapid procedure for the synthesis of dimethyl-2-[3-amino-5-(2-methoxy-2-oxoethylidene)-4-oxothiazolidin-2-ylidenehydrazono]succinate, dimethyl {[2-alkylidenehydrazono)-5-(2-methoxy-2-oxoethylidene)-4-oxothiazolidin-3-yl)amino]succinate and methyl (4-amino-5-oxo-3-thioxo-2,3,4,5-tetrahydro-1,2,4-triazine-6-yl)acetate affording yields of 61–54 %, 22–18 % and 14–11 %, respectively, via a condensation reaction of dimethyl acetylenedicarboxylate (DMAD) with (substituted ylidene)thiocarbonohydrazides. One of the products was conclusively confirmed by single-crystal X-ray analysis. A mechanism for the formation of the products is presented.