obtained starting from easily available materials and involving the cyclization of diarylamines. The first step of the preparation consists in a SNAr reaction between a para substituted aniline and a chloro- (or bromo)-dinitrobenzene. This nucleophilicsubstitution has been found to be hindered by the steric effect of a methyl group, explained in terms of inhibition of resonance and confirmed by X-ray determination
3-氰基咔唑,是吡啶并[4,3- b ]咔唑全合成中的关键中间体,已从易于获得的材料开始,涉及二芳基胺的环化反应。制备的第一步在于对位取代苯胺与氯-(或溴)-二硝基苯之间的S N Ar反应。已经发现这种亲核取代被甲基的空间效应所阻碍,这在抑制共振方面得到了解释,并通过X射线测定得到了证实。
Sodium dithionite in the regioselective reduction of the ortho-positioned nitro group in 1-R-2,4-dinitrobenzenes
作者:Michael D. Tsymliakov、Anita I. Maksutova、Elena N. Bezsonova、Daria V. Zakharova、Yuri K. Grishin、Victor A. Tafeenko、Sergey E. Sosonyuk、Natalia A. Lozinskaya
DOI:10.1016/j.mencom.2023.01.038
日期:2023.1
1-R-2,4-Dinitrobenzenes are regioselectively reduced with sodiumdithionite at near-neutral pH into the product having amino group ortho to the substituent R. Although the yields of products varied from moderate to good, the procedure does not involve the use of transition metals.