Efficient and Regioselective Synthesis of 2-Alkyl-2H-indazoles
摘要:
An efficient and regioselective synthesis of 2-methyl-2H-indazoles and 2-ethyl-2H-indazoles using trimethyloxonium tetrafluoroborate or triethyloxonium hexafluorophosphate is reported.
On the reactions of tertiary carbanions with some nitroindazoles and nitrobenzotriazoles
作者:Marek K. Bernard、Jacek Kujawski、Urszula Skierska、Andrzej K. Gzella、Wojciech Jankowski
DOI:10.3998/ark.5550190.0013.816
日期:——
The vicarious nucleophilic substitution in some nit roindazole and nitrobenzotriazole derivatives with tertiary carbanions leads almost exclusively t o products substituted para to the nitro group. As results from the theoretical calculations and st ructural evidences, such reaction outcome is due mainly to the stereoelectronic reasons in combi nation with the considerable shortening of the Cortho
某些硝基罗吲唑和硝基苯并三唑衍生物中的替代亲核取代与叔碳负离子几乎完全导致产物在硝基的对位被取代。从理论计算和结构证据来看,这种反应结果主要是由于立体电子学的原因和Cortho-CNO 2 键的显着缩短相结合。手性和前手性中心(分别为次甲基和 N 亚甲基基团)的存在通常会引起亚甲基质子信号的额外分裂,该信号在长距离上传输,前提是偶联途径中没有吡啶氮。
Selective N2-Alkylation of 1H-Indazoles and 1H-Azaindazoles
作者:Allyn T. Londregan、Jennifer Clemens、Emily L. Bell
DOI:10.1055/s-0040-1719917
日期:2022.7
A general and selective procedure for the N2-alkylation of 1H-indazoles and 1H-azaindazoles is presented. Promoted by either trifluoromethanesulfonic acid or copper(II) triflate, diverse 1H-indazoles/azaindazoles are selectively alkylated with varied primary, secondary, and tertiary alkyl 2,2,2-trichloroacetimidates at the N2-nitrogen to afford the corresponding 2-alkyl-2H-indazoles/azaindazoles. Forty-one