Convenient synthesis of some new pyrazolo[5,1-c]triazines, isoxazolo[3,4-d] pyrimidine and pyridine derivatives containing benzofuran moiety

Reactivity of Benzofuran Derivatives

“…Treatment of the product with hydrazine hydrate gave isoxazolo [3,4-d]pyridazine 27a respectively [17] (Scheme 7).…”

“…The latter was reacted with aryldiazonium chlorides in ethanolic sodium acetate solution to afford 21a and 21b [17] (Scheme 6).…”

“…Pyrazolo [5,1-c] [1,2,4]triazine derivatives containing benzofuran moiety 14 were synthesized via reaction of sodium salt of l-benzofuran-2-yl propenone 10 (which is prepared via Claisen condensation of 9 with ethylformate in sodium methoxide) with diazotized heterocyclic amines 11 [17] 18 and benzo [4,5]imidazo[2,1-c]- [1,2,4]triazin-3-ylbenzofuran-2-yl-methanone 19, respectively, in good yield [17] (Scheme 5).…”

Chemistry of Pyrazole-3(5)-Diazonium Salts (Review)*

“…The reaction was performed in aqueous or aqueous-alcoholic alkali solutions at low or room temperature through the stage of pyrazolylhydrazones 90 or their sodium salts 91. Treatment of the former with alkali solution gave the respective azinium salts 92, which were transformed into nitro-substituted dihydropyrazolo [5,1-с A method for the synthesis of 4H-pyrazolo[5,1-с][1,2,4]triazines 100, using the enaminones 99 as activated methylene compounds in reactions with pyrazole-3(5)-diazonium salts, was developed by a research group from Egypt [176][177][178][179][180]. The proposed mechanism involves initial formation of azo compounds А, which condense under the reaction conditions, giving pyrazolotriazines 100 either directly through elimination of a dimethylamine molecule or through hydrolysis and dehydration stages.…”

Synthesis, characterization and antimicrobial evaluation of 1-((5,3-diaryl)-4,5-dihydro-1H-pyrazol-1-yl)propan-1-one

“…It is worthy of note that substances containing a 1H-pyrazole moiety have been described as having potential therapeutic utility, such as antiinflammatory [3][4][5], antidepressant [6,7], antipyretic [8], antibacterial [9][10][11][12][13][14], antifungal [12,15] and antitumoral [16]. Of particular interest is the use of 1H-pyrazoles as synthetic intermediates for preparing cyclopropane [17][18][19] and pyrazole derivatives [1,[20][21][22][23][24][25][26]. 1H-Pyrazoles have usually been prepared by starting from aldehydes or ketones, which have either actual or potential α,β-unsaturation [1,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41].…”