The reaction of arenealdehyde 4-phenylthiosemicarbazones 1a-f with dimethyl ethynedicarboxylate (6) gave methyl [3-aryl-4-oxo-1-(phenylthiocarbamoyl)-4,5-dihydro-1H-pyrazol-5-ylidenelethanoates 10a-f in 73-79% yield, while, by reaction with diethyl (E)-2,3-dicyanobutenedioate (7), compounds 1a-f are transformed into ethyl [3-aryl-4-oxo-1-(phenylthiocarbamoyl)-4,5-dihydro-1H-pyrazol-5-ylidenelcyanoacetates 15a-f (54-61%) and ethyl 3-amino-6-aryl-5cyanopyridazine-4-carboxylates 24a-f (22-26%). Rationales for these transformations are presented.

In a multistep reaction, indeno [2,1-e][1,3,4]oxadiazine-9-one, oxoindeno[1,2-c]-pyrazolecarbothioamide, (thioxo-1,2,4-triazaspiro[4.5]decadienylidene)malononitrile and spiro-(fluorine-9,3'-[1,2,4]triazoline)-5'-thione derivatives have been formed from a series of (substituted ylidene)-N-phenylhydrazinecarbothioamides 1a-e with (1,3-dioxo-2,3-dihydro-1H-inden-2-ylidene)propanedinitrile, 7,7',8,8'-tetracyanoquinodimethane and (2,4,7-trinitro-9H-fluoren-9-ylidene)propanedinitrile in aerated pyridine. Rationales of these conversions involving the nucleophilic reactions, condensation, dehydrogenation and oxidation are presented.

Pyrazole derivatives R 0180Formation of 5-Alkylidenepyrazol-4(1H)-ones and 3-Amino-6-aryl-5-cyanopyridazine-4-carboxylates from Arenealdehyde Thiosemicarbazones and Unsaturated 1,2-Diesters. -The reaction of arenealdehyde thiosemicarbazones with acetylene dicarboxylates (II) yields pyrazole derivatives of type (III). From the reaction with (IV) pyrazole derivatives of type (V) and pyridazine derivatives of type (VI) are obtained. Possible reaction mechanisms are discussed. -(HASSAN, A. A.; SHEHATA, H. S.; DOEPP*, D.; J. Chem. Res. 2008, 12, 725-730; Fachber. Chem., Univ. Duisburg-Essen, D-45117 Essen, Germany; Eng.) -M. Bohle 21-115

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.