8-Aryloct-7-en-2,4,6-triones as Useful Precursors for the Regioselective Synthesis of Some New 2-Methyl-5-styryl-7-thioxo-6,7-dihydropyrazolo[1,5-c]pyrimidines

Dehydroacetic acid, commonly abbreviated as DHA, and its derivatives have been extensively used as important intermediates in organic synthesis particularly for the synthesis of heterocyclic compounds. The reaction of 8-aryloct-7-en-2,4,6-triones (DHA-triones, readily prepared from commercially available DHA by the use of a multistep procedure) with thiosemicarbazide led the formation of some new 2-methyl-5-styryl-7-thioxo-6,7-dihydropyrazolo[1,5-c] pyrimidines.