A synthetic route to bicyclic pyrazolenines via 3-chloropyrazolines and the ring opening of pyrazolenines to diazoalkenes

Y Nakano, M Hamaguchi, T Nagai

Index: Nakano, Yoshihiko; Hamaguchi, Masashi; Nagai, Toshikazu Journal of Organic Chemistry, 1989 , vol. 54, # 25 p. 5912 - 5919

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Citation Number: 18

Abstract

Treatment of 5, 5-disubstituted 3-chloro-l-pyrazolines, derived from the reaction between disubstituted diazomethmes and dimethyl chlorofumarate, with triethylamine gives the corresponding 3, 3-disubstituted 3H-pyramles in good yield. This method was applied to the synthesis of bicyclic pyrazolenines. The system fused to a five-membered imide ring did not afford 3H-pyrazoles but the diazoalkenes (20b-e), formed by thermal ring opening of the ...