Heterocyclic synthesis containing bridgehead nitrogen atom: Synthesis of 3‐[(2H)‐2‐oxobenzo[b]pyran‐3‐yl]‐s‐triazolo[3,4‐b]‐1,3,4‐thiadiazine and thiazole derivatives

Abstract

The reaction of 2H-2-oxobenzo[b]-pyran-3-hydrazide (2)

Heterocyclic Synthesis Via Enaminonitriles: One-Pot Synthesis of Some New Pyrazole, Pyrimidine, Pyrazolo[1,5-A]Pyrimidine and Pyrido[2,3-D]Pyrimidine Derivatives

“…The 1H NMR spectrum exhib ited singlet signal at  4.88 ppm due to NH2 protons which was attributed to (41) which is consistent isomeric structure (41) specific for three NH protons, in addition to an aro mat ic mu ltip let in the region  7.21-7.83 ppm. In addit ion, according to literature the reaction of hetercyclic amines to the double bond of the enaminonitrile occurs with concurrent elimination of dimethylamine rather than condensation of water mo lecule [45][46][47][48][49][50][51][52][53][54][55][56][57] but in our studying herein elimination of dimethylamine rather than addition on cyano group followed by aro mat ization. On the basis of these finding, structure of (38 and 40) was discarded and the product isolated fro m the studied reaction was assigned structure (41).…”

“…In connection with our previous studies [45][46][47][48][49][50][51][52][53] and in view of utilizing the cyan-oacetamide as highly versatile intermediates for the construction of functionlized pyrazole, pyrimidinethione pyrazolopyrimid ine and pyridopyrimidine derivatives of expected potential b iological activity and excellent pharmacology encouraged us to synthesis novel entitled derivatives. …”

Progress in the chemistry of 4‐ thiazolidinones

“…Reaction of hydrazide 22 with the appropriate aromatic aldehydes gave the arylidenehydrazinocarbonyl 23, which on condensation with thioglycolic acid in dry benzene gave thiazolidinone derivatives 24 [63][64][65][66]. …”

Synthesis of pyrazole, 1,3-dithiolan and thiophene derivatives pendant to thiazolo[2,3-c]-1,2,4-triazole moiety

“…Based on the above observations, we expected that incorporation of the above various nuclei will yield compounds with enhanced biological activities and as a part of our research program aimed at developing simple and efficient synthetic approaches for fused ring systems with bridgehead nitrogen atom, utilizing the inexpensive and readily obtainable starting materials like 5-acety-2-amino-4-methylthaizole [30][31][32][33][34][35], we report here on the utility of the highly versatile, multifunctional intermediates 6 and 7 as building blocks for the synthesis of the title compounds.…”