Highly regioselective synthesis of novel 1,4'-bipyrazoles
摘要:
Novel 1,4'-bipyrazoles were synthesized via highly regioselective cyclocondensation reactions of b-dimethylaminoenones with hydrazine monohydrate, tert-butylhydrazine hydrochloride, phenylhydrazine hydrochloride or carboxymethylhydrazine. X-ray diffraction technique was used in the elucidation of the regiochemistry of the beta-dimethylaminoenaminones and of the 1,4'-bipyrazoles. 1,4'-Bipyrazolylisoxazoles were also reported.
Highly regioselective synthesis of novel 1,4'-bipyrazoles
摘要:
Novel 1,4'-bipyrazoles were synthesized via highly regioselective cyclocondensation reactions of b-dimethylaminoenones with hydrazine monohydrate, tert-butylhydrazine hydrochloride, phenylhydrazine hydrochloride or carboxymethylhydrazine. X-ray diffraction technique was used in the elucidation of the regiochemistry of the beta-dimethylaminoenaminones and of the 1,4'-bipyrazoles. 1,4'-Bipyrazolylisoxazoles were also reported.
Ag2CO3 catalyzed aza-michael addition of pyrazoles to α, β-unsaturated carbonyl compounds: A new access to N-alkylated pyrazole derivatives
作者:Xue Zhang、Dong-xue Qiu、Wen-ting Qiu、He-ran Wang、Zu-wei Zhao、Hai-feng Yu、Guang-bo Che
DOI:10.1016/j.tet.2023.133305
日期:2023.3
catalyzed aza-Michael addition of pyrazoles to α, β-unsaturated carbonyl compounds is developed. In the present of 5 mol% of Ag2CO3, the reaction smoothly occurs in DCE at 120 °C to afford a series of N-alkylated pyrazoles in good to excellent yields. It is noteworthy that N1-alkylated pyrazoles are obtained with high regioselectivity (N1/N2 up to above 25:1) when asymmetrically substituted pyrazoles reacted
开发了一种有效的 Ag 2 CO 3催化吡唑氮杂迈克尔加成 α, β-不饱和羰基化合物。在 5 mol% 的 Ag 2 CO 3存在下,反应在 DCE 中在 120 °C 下顺利发生,以良好至优异的产率提供一系列N-烷基化吡唑。值得注意的是,当不对称取代的吡唑与α,β-不饱和羰基化合物反应时, N 1 -烷基化的吡唑具有高区域选择性(N 1 /N 2高达25:1以上)。该方法还可以扩展到克级。
Highly regioselective synthesis of novel 1,4'-bipyrazoles
作者:Marcos A. P. Martins、Gabriela F. Fiss、Clarissa P. Frizzo、Fernanda A. Rosa、Helio G. Bonacorso、Nilo Zanatta
DOI:10.1590/s0103-50532010000200008
日期:——
Novel 1,4'-bipyrazoles were synthesized via highly regioselective cyclocondensation reactions of b-dimethylaminoenones with hydrazine monohydrate, tert-butylhydrazine hydrochloride, phenylhydrazine hydrochloride or carboxymethylhydrazine. X-ray diffraction technique was used in the elucidation of the regiochemistry of the beta-dimethylaminoenaminones and of the 1,4'-bipyrazoles. 1,4'-Bipyrazolylisoxazoles were also reported.