Benzazoles and naphthazoles XXXIV. Synthesis of mono-, di-, and triheterylformazans by autooxidation of 2-hydrazinobenzazoles

3-Aryl[1,2,4]triazino[4,3-a]benzimidazol-4(10H)-ones: A New Class of Selective A1 Adenosine Receptor Antagonists

“…Biological Evaluation of Compounds 1 − 22. To better delineate the SARs of ATBI derivatives, five new compounds ( 18 − 22 ), with respect to those described as BzR ligands ( 1 − 17 ), were prepared by reacting 1-methyl-2-hydrazinobenzimidazole 29 with the appropriate glyoxylic acids following experimental procedures similar to those previously reported to obtain the corresponding N10-H analogues 1 , 2 , 6 , 8 , and 11 1 (Scheme , Tables and ). All the compounds 1 − 22 (Table ) were tested in radioligand binding assays to determine their affinities at the bovine A 1 , A 2A , and A 3 ARs.…”

“…The new compounds 23 , 24 , and 25 − 28 were prepared starting from the appropriate 2-hydrazinobenzimidazole derivatives 30 and 31 , respectively (Scheme ). 1-Benzyl-2-hydrazinobenzimidazole 31 was obtained by a synthetic procedure reported in the literature . We used the same procedure to prepare the already described 2-hydrazino-1-phenylbenzimidazole 30 from hydrazine hydrate and 2-chloro-1-phenylbenzimidazole.…”

[1,2,4]Triazino[4,3-a]benzimidazole Acetic Acid Derivatives: A New Class of Selective Aldose Reductase Inhibitors

“…mp 73−75 °C); 2-chloro-1-(4-fluorobenzyl)benzimidazole, 33 , mp 74−79 °C (lit . mp 75−76 °C); 2-hydrazinobenzimidazole, 37 , mp 148−151 °C (lit . mp 146−147 °C); 1-benzyl-2-hydrazinobenzimidazole, 40 , mp 134−135 °C (lit .…”

“…mp 75−76 °C); 2-hydrazinobenzimidazole, 37 , mp 148−151 °C (lit . mp 146−147 °C); 1-benzyl-2-hydrazinobenzimidazole, 40 , mp 134−135 °C (lit . mp 140−145 °C); [1,2,4]triazino[4,3- a ]benzimidazol-3,4(10 H )-dione 48 , mp >300 °C (lit .…”

“…The substituted 1-alkyl-2-chlorobenzimidazoles 27 − 36 (Table ) were prepared in good yields from the commercially available 2-chlorobenzimidazole 26 by reaction with the appropriate alkyl halide in the presence of sodium hydride . Treatment of 26 − 36 with hydrazine hydrate resulted in the hydrazino derivatives 37 − 47 (Table ), which were cyclized to the corresponding triazinobenzimidazoles 48 − 58 (Table ) by refluxing with an equimolar amount of diethyl oxalate in ethanolic solution . Reaction of 48 − 58 with ethyl bromoacetate in refluxing acetone, in the presence of anhydrous potassium carbonate, gave the ester derivatives 59 − 69 (Table ).…”