A. A. Atalla

SOME RING CLOSURE REACTIONS WITH CYANOTHIOFORMAMIDES: NEW ROUTE FOR THE SYNTHESIS OF (IMIDAZOLIDINE, OXAZOLIDINE & PYRROLINE)-IMINOTHIONES, BENZOTHIAZOLOQUINAZOLINONES AND IMIDAZOQUINOXALINES

Abstract Cyanothioformarnides were reacted with isocyanates, isothiocyanates, aldehydes, acetylenedicarboxylic acid and anthranilic acids to produce imidazolidines, oxazolidines pyrroline, quinazolinones and benzothiazoloquinazolinones, respectively. Interaction of imidazolidineimino(thiones and dithiones) with o-phenylenediamines gave rise to imidazoquinoxalines and imidazoquinoxalinethiones, respectively.

SOME CYCLIZATION REACTIONS WITH 4-THIOHYDANTOIN: SYNTHESIS OF SOME NOVEL THIOPYRANOIMIDAZOLES, THIENOIMIDAZOLES AND IMIDAZOQUINOLINES AND SOME METAL COMPLEXES WITH BIOLOGICAL INTEREST

Abstract 4-Thiohydantoin (II) with chloroacetic acid, chloroacetanilides and cyanothioformamides gave thieno[2,3-d)imidazoles (IV, V and IX), respectively. α,β-Unsaturated nitriles and anthranilic acids reacted with (II) to produce thiopyrano[2,3-d]imidazoles (III) and imidazo[4,5-b]quinolines (VII). Some metal complexes were prepared and the antimicrobial activity of some selected compounds was also reported.

Phenylacetone as Building Blocks in Heterocyclic Synthesis: Synthesis of Polyfunctionally-Substituted Pyridines, and fused Pyridines

Many pyridinethiones are biologically active. In view of our interest in developing efficient syntheses of polyfunctionally substituted heteroaromatics utilizing the readily obtainable enaminone 3 as starting materials. So, treatment of enaminone 3 with cyanothioacetamide or cyanoacetamide afforded the pyridinethione 5a and pyridone 5b. compound 5a reacted with α -halo- ketones in refluxing sodium ethoxide to give the thienopyridine derivatives 9a – e . Compound 5a reacted with methyl iodide to give 2-methylthiopyridine 10. Condensation of pyridinethione 5a with dimethylformamide-dimethylacetal gave the adduct 11 and with hydrazine hydrate afforded 12 . Compound 5a reacted with arylidenemalonitrile to give styryl derivatives 14a – d . Compound 14a – d also prepared from the condensation of 5a with the aromatic aldehydes under the same condition. Reflux of thienopyridine derivatives 9a – d with triethylorthoformat, acetic anhydride, carbon disulfide and sodium nitrite to give compounds 19 – 23 , respectively. The aminopyrazole 12 reacted with dimethylaminopropiophenone hydrochloride 24 or enaminone 30 in refluxing DMF to yield compound 26a – d . Treatment of 12 with 32 afforded 34 . Compound 34 can be also prepared from the reaction of 37 with aroylacetonitrile 31. Compound 12 reacted with DMF-DMA to give 37 , which reacted with compound 1 to give 38 prepared directly from reaction of 12 with enaminone 2 . Diazotization of 12 with nitrous acid followed by coupling with different active methylene reagents afforded the pyridothienotriazines 42a , b . Reaction of benzylideneacetophenone with 12 yielded the pyridopyrazolopyrimidine 44. Also, compound 12 reacted directly with active methylene to give the pyridopyrazolopyrimidine derivatives 46a , b .

MOLECULAR REARRANGEMENT OF SULFUR COMPOUNDS(VII). PYROLYSIS OF ARENESULFONYLHYDRAZINE DERIVATIVES

Abstract N-Phenyl-N′-arenesulfonylhydrazine(I-II) on pyrolysis by refluxing in an atmosphere of nitrogen at ca. 240°C give SO2, H2S, NH3, arene, biaryl, aniline, azobenzene, diaryl sulfide, diaryl sulfone, arenesulfonic acid, phenyl hydrazine and carbazole derivatives. N-Benzylidene-N′-benzenesulfonythydrazone(III) on similar treatment gives the previous products in addition to benzonitrile, bibenzyl, stilbene, 2-phenylindole and 2,3,4,5-tetraphenylthiophene. The observed results have been interpreted in terms of a free radical mechanism involving the homolysis of N[sbnd]N and S[sbnd]N bonds.

MOLECULAR REARRANGEMENT OF SULFUR COMPOUNDS. PART V: PYROLYSIS OF MERCAPTOOXADIAZOLE DERIVATIVES

Abstract Pyrolysis of 5-phenyl-2-benzylthio-1,3,4-oxadiazole (1) by heating at ca. 250°C in a sealed tube gives rise to CO2, H2S, H2O, benzyl thiocyanate, benzonitrile, benzyl sulfide, aniline, benzamide, benzaldehyde, 2-mercaptoquinazolinone, dibenzyl, stilbene, and tetraphenylthiophene. Furthermore pyrolysis of 5-phenyl-2-phenacylthio-1,3,4-oxadiazole (9) gives analogous results, besides phenancyl thiocyanate. Pyrolysis of 5(2-hydroxyphenyl)-2-benzylthio-1,3,4-oxadiazole (11) gives 2-hydroxybenzonitrile, 5(2-hydroxyphenyl)-1,3,4-oxadiazole-2-thiol, and 2-hydroxybenzamide, in addition to the previous obtained results. The mechanism of these results has been discussed.

The reactions of 4‐substituted‐7‐aminothieno‐[3,4‐d]pyridazines and 2‐methyl‐6‐aminothienopyridine‐5‐thione with electron‐poor olefins and acetylenes

Cycloadditions of thienopyridazines and a thienopyridine with electron-poor olefins and acetylenes as dienophiles are described. The nonisolable adducts undergo subsequent loss of hydrogen sulfide to give substituted phthalazines and substituted isoquinolines, respectively.

Molecular rearrangement of sulfur compounds (IV) pyrolysis of 2-arylimino-3-aryl-5-benzylidenethiazolidin-4-one

Abstract Thermal rearrangement of 2-arylimino-3-aryl-5-benzylidene-thiazolidin-4-ones (I-IV) by reflux in air at 250°C has been thoroughly investigated. The isolated products are H2S, CO, CO2, ammonia, water, arylamines, aryl isothiocyanates, benzothiophenes, arylnitriles, arylurea derivatives, arylthiourea derivatives, 2-arylquinolines, benzimidazole derivatives and polystyrene. With compound III, in addition to the previous products benzaldehyde, bibenzyl, stilbene, bibenzylamine, benzylcyanamide and 2,3,4,5 tetraphenylthiophene were obtained. Free radical mechanisms involving homolysis of C[sbnd]S and C[sbnd]N bonds have been suggested to account for the identified products.

MOLECULAR REARRANGEMENTS OF SULPHUR COMPOUNDS (II)† PYROLYSIS OF SOME SUBSTITUTED THIAZOLIDINONES

Abstract Thermal rearrangement of 2,3-diarylthiazolidine-4-one (I and II) provided H2S, H2O benzene and its alkyl derivatives, thioglycolic acid, aromatic primary amine, benzonitrile, biaryl, tetraphenylthiophene, indole derivatives, benzil, acetophenone derivatives and benzthiazole derivatives. A suitable mechanism has been suggested which explains the obtained products.

MOLECULAR REARRANGEMENT OF SULPHUR COMPOUNDS (PART I). PYROLYSIS OF SOME SUBSTITUTED RHODANINE

Abstract Thermal rearrangement of 3-phenylrhodanine (I) and 5-benzylidene-3-phenylrhodanine (IV) in air has been thoroughly investigated. Homolytic cleavage of (C—S) and (C—N) bonds occurred, followed by a series of hydrogen abstractions, coupling, and cyclization reactions. The isolated products of compound (I) are CS2, CO, H2S, NH3, aniline, dibenzylamine, tribenzylamine, thioglycolic acid, phenyl isothiocyanate, bibenzyl. stilbene, p-arninoacetophenone, thiocarbanilide, 2-thioxoindole and 2,3,4,5-tetraphenylthiophene. In case of compound (IV), the isolated products are CS2, H2S, H2O, CO, phenyl isothiocyanate, benzothiophene, 2-phenylquinoline, aniline, thiocarbanilide, 2-phenylindole, cinnamic acid and polystyrene. A suitable mechanism has been suggested to account for the obtained products.

MOLECULAR REARRANGEMENTS OF SULFUR COMPOUNDS PART VIII. PYROLYSIS OF 2-(N-SUBSTITUTED CARBOXAMIDO-METHYLTHIO)-5-ARYLAMINO-1,3,4-THIADIAZOLE DERIVATIVES

Abstract Pyrolysis of 2-(N-substitutedcarboxamidomethylthio)-5-arylamino-1,3,4-thiadiazoles(I-III) at ca 210°C in boiling tetralin for 8 hrs or neat at ca 250°C for 5 hrs affords hydrogen sulfide, aryl isothiocyanate, arylcyanamide, benzimidazole derivatives, 4-aryl-1,2,4-triazole, thioglycolicanilides, 4-aryl-δ2-triazoline-5-thione and 3-aryl-2-thiohydantoin derivatives. A free radical mechanism has been suggested to account for the obtained products.