An efficient in-situ reduction and cyclization reaction for the synthesis of 9-aryl-1,6,8,9-tetrahydro-7 H -pyrazolo[3,4- f ]quinolin-7-one, 11-aryl-1,6,7,8,9,11-hexahydro-10 H -pyrazolo [3,4- a ]acridin-10-one, and 11-aryl-3,6,7,8,9,11-hexahydro-10 H -imidazo[4,5- a ]acridin-10-one derivatives

• DOI: 10.1016/j.tet.2017.10.040
• Publication Date: 2017-10-17T02:19:26Z
• Authors: Lirong Yan; Qingyang Li; Hui Xu; Zhongyun Xu; Qiuyu Yu; Yaqi Qin; Liangce Rong
• Keywords: 01 natural sciences; 0104 chemical sciences

Abstract An efficient in-situ reduction and cyclization reaction was reported from the aromatic aldehydes, 6-nitro-1H-indazole (5-nitrobenzimidazole), and 2,2-dimethyl-1,3-dioxane-4,6-dione (1,3-cyclohexanedione or dimedone) to synthesize 9-aryl-1,6,8,9-tetrahydro-7H-pyrazolo[3,4-f]quinolin-7-one, 11-aryl-1,6,7,8,9,11-hexahydro-10H-pyrazolo [3,4-a]acridin-10-one, and 11-aryl-3,6,7,8,9,11-hexahydro-10H-imidazo[4,5-a]acridin-10-one derivatives in the presence of SnCl2·2H2O in THF medium. The advantages of this method are mild conditions, convenient manipulation, high yields and wide range of substrates.