Pyrazolo[3,4-<i>b</i>]pyridines: Syntheses, reactions, and nuclear magnetic resonance spectra
作者:Brian Maurice Lynch、Misbahul Ain Khan、Huk Chia Teo、Francisco Pedrotti
DOI:10.1139/v88-074
日期:1988.3.1
2-Chloro-3-formylpyridine (2-chloronicotinaldehyde) was obtained by reduction of 2-chloro-3-cyanopyridine by Raney nickel and formic acid (3 1); this intermediate is inaccessible by the above N-oxidation route (peroxyacid oxidation of 3-formylpyridine yields pyridine-N-oxide 3-carboxylic acid). In the synthesis of the parent 1 from 2-chloro-3-formylpyridine, the yield was prejudiced by the formation
diarylpyrazolo[3,4-b]pyridine derivatives by a combination of chemoselective Suzuki–Miyaura cross-coupling reactions was developed. The sequential arylation strategy can be performed in a one-pot manner without much loss of efficiency when compared to the corresponding stepwise synthesis. These conditions are applicable to the coupling of a wide variety of aryl and heteroaryl-boronic acids with pyrazolo[3
开发了一种通过化学选择性 Suzuki-Miyaura 交叉偶联反应合成二芳基吡唑并[3,4- b ]吡啶衍生物的实用方法。与相应的逐步合成相比,顺序芳基化策略可以一锅法进行,而不会大大降低效率。这些条件适用于多种芳基和杂芳基硼酸与吡唑并[3,4- b ]吡啶的偶联,C3对C6位具有高选择性,从而能够快速构建多种药物重要的二芳基吡唑并[3,4- b ]吡啶。