Synthesis of trifluoromethyl-promoted functional pyrazolo [1, 5-a] pyrimidine and pyrazolo [5, 1-d][1, 2, 3, 5] tetrazine-4 (3H)-ones

…, YJ Chen, HJ Li, XM Zou, FZ Hu, HZ Yang

Index: Wu, Yan-Chao; Chen, Yong-Jun; Li, Hui-Jing; Zou, Xiao-Mao; Hu, Fang-Zhong; Yang, Hua-Zheng Journal of Fluorine Chemistry, 2006 , vol. 127, # 3 p. 409 - 416

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Citation Number: 24

Abstract

Ethyl 5-amino-3-trifluoromethyl-1H-pyrazole-4-carboxylate (1) was efficiently synthesized via the condensation of ethyl cyanoacetate and trifluoroacetic anhydride, followed by chloridization and the condensation with aqueous hydrazine. Its unique reactivity was exploited for the synthesis of trifluoromethylated pyrazolo [1, 5-a] pyrimidine (5) and pyrazolo [5, 1-d][1, 2, 3, 5] tetrazine-4 (3H)-ones (8a–j). Among them, 5 was firstly found to be a ...