Synthesis of New Indeno[1,2‐c]pyrazole‐Based Heterocycles and Evaluation of Their Protective Effect against DNA Damage Induced by Bleomycin–Iron

Abstract

image Reaction of potassium 2‐(1‐phenyl‐1,4‐dihydroindeno[1,2‐c]pyrazole‐3‐carbonyl)hydrazine carbodithioate (2) with hydrazine hydrate, phenacyl bromides, and hydrazonoyl chlorides afforded the corresponding 1,2,4‐triazole, 1,3‐thiazole, and 1,3,4‐thiadiazole derivatives 3, 5, and 7, respectively. Reaction of 3‐mercapto‐4‐amino‐1,2,4‐triazole 3 with phenacyl bromides 4a–c and hydrazonoyl chlorides 6a,b afforded the corresponding 1,2,4‐triazolo[3,4‐b]‐1,3,4‐thiadiazine derivatives 10a–c and 13a,b, respectively, whereas its reaction with 2‐chloro‐N‐arylacetamide derivatives 11a–d afforded the corresponding 2‐(4‐amino‐5‐(1‐phenyl‐1,4‐dihydroindeno[1,2‐c]pyrazol‐3‐yl)‐4H‐1,2,4‐triazol‐3‐ylthio)‐N‐arylacetamide derivatives 12a–d. All of the new compounds were tested for their protection activity against DNA damage induced by bleomycin–iron complex. Compounds 7a and b showed the highest protection activity through diminishing chromogen formation between the damaged DNA and thiobarbituric acid.