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Treating 5-(4-phenylcarboxamido)-3-cyano-4-methylpyridin-2(1H)thione (3) with elemental sulfur yielded thienopyridine 4. Compound 4 reacts with acrylonitrile to give isoquinoline 7. Compound 7 was also, prepared from 3 and methylenemalononitrile. Reaction of 3 with dimethylacetylene dicarboxylate (DMAD) gave the pyridothiazole 9. Also, 3 reacted with N,N-dimethylchloroacetamide (10) to afford compound 11 which further reacted with the reagents 12, 13 and 14 providing the thieno[2,3-b]pyridine derivatives 15, 16 and 17 respectively.

5-Aminopyrazole 1 was condensed with aryl aldehydes to give the 4-arylidenes 2. Compound 2 reacted with thioglycolic acid and ethyl cyanoacetate to give the pyrazolothiazepines 3 and pyrazolopyrimidines 4, respectively. Diazotized 2a coupled with resorcinol to give the pyrazole derivative 5a. Reaction of 1a with β-keto esters 7, 8 and acetoacetanilides 13 afforded the pyrazolopyrimidines 11, 12 and 15, respectively. Condensation of 1a with 2-acetylindan-1,3-dione 16 yielded fused pyrazolopyrimidine 18. Compound 1a also reacted with the enaminonitriles 19 and 22 to give the pyrazolopyrimidine 20 and 24, respectively.

Several isoquinolines were prepared via reacting pyridine 4 with cinnamonitriles 5a-c or 5d-f. Treating 4 with elemental sulphur yielded thienopyridine 9. 9 reacts with acrylonitrile to give isoquinoline 12. 12 was also prepared from 4 and methylenemalononitrile. Condensation of 4 with aromatic aldehydes gave the arylidine 13. 13 afforded the pyridine 14 and 15 on treating it with NH4OH and AcOH/HCl, respectively.

Acetoacetanilide 1 reacted with DMF-DMA to give the enaminone 2. Compound 2, when treated with hydrazines gives the pyrazoles 4a and 4b respectively, and with pyrazole derivatives Sa and 5b the pyrazolopyrimidines 7. On the other hand, in reaction of 2 with benzimidazole and benzimidazole-2-acetonitrile, the pyrimidobenzimidazole 14 and the pyridobenzimidazole 17 were formed. 2 reacts with hippuric acid in boiling acetic anhydride to afford the pyridine 20. In the reaction of 2 with malononitrile, cyanoacetamide or malononitrile dimer compounds 21, 22 and 24 were formed. Compound 22 was further reacted with arylidenemalononitriles to give the benzopyridine derivatives 28. Pyridone 22 treated with S-DMF mixture gives thienopyridine 29, while refluxed with DMFDMA yielded the pyridopyridine 30.

On heating of the cyanoacetic acid cyclopentylidene hydrazide 1 with salicylaldehyde in the presence of bases the azaanthracene derivative 6 was formed. Also, reaction of 3 with malononitrile and ketones 10a,b afforded the pyrano[3,4-c]chromene 9 and chromeno[3,4-c]pyridine 11 respectively. A mechanism for these reactions is proposed.

The enaminone 2 reacts with 5-aminopyrazole derivative 3 and 2-aminobenzimidazole 5 in refluxing acetic acid to afford the diazacyclopentafluorene derivative 4 and the triazaindenofluorene derivative 6 respectively. Also,2 reacted with benzamidine hydrochloride hydrate 7 in dry pyridine to give the indenopyrimidine derivative 8. The reaction of 2 with lH-benzimidazole-2-yl-acetonitrile 9, 4-cyanoacetylphenazone 11 and malononitrile, yielded the indenofluorene 10, indenopyran 12, and fluorenone 13 respectively.

The hydrazone 1 reacts with DMFDMA to give 2-dimethylaminomethylene-3-(phenylhydrazono)-indan-1-one (2) which reacts with hydrazine hydrate and the pyrazole derivative 4 to afford the indenopyrazole derivatives 3 and the indenofluorene 5 respectively. The reaction of 2 with the active methylene compounds, mainly malononitrile, cyanoacetamide and malononitrile dimer was investigated and found to proceed successfully to yield the indenopyran 7, indenpyridine 8b and trinitrile 9 respectively. Compound 2 reacted with lH-benzimidazole-2-acetonitrile 10 to give to the diazaindenofluorene derivative 11. Also, 2 reacted with ω-cyano compounds 12a,b to afford the indenopyran 14. On the other hand the hydrazone 1 was allowed to react with the enaminones 15, 18 and 21 affording the diazabenzoazulene derivatives 17, 20 and the indeno[1,2-b]pyridin 23, respectively.

The reaction of 6-hydrazinopyrimidine-2,4-dione derivative 1 with alkyl or aryl isocyanates 2a-d resulted in a novel and facile synthesis of pyrazolo[3,4-d]pyrimidine derivative 5a-d in good yield.

The enaminone 2 reacts with 5-aminopyrazole derivative 3 and 2-aminobenzimidazole 5 in refluxing acetic acid to afford the diazacyclopentafluorene derivative 4 and the triazaindenofluorene derivative 6 respectively. Also,2 reacted with benzamidine hydrochloride hydrate 7 in dry pyridine to give the indenopyrimidine derivative 8. The reaction of 2 with lH-benzimidazole-2-yl-acetonitrile 9, 4-cyanoacetylphenazone 11 and malononitrile, yielded the indenofluorene 10, indenopyran 12, and fluorenone 13 respectively.