一种新的二聚反应,产生2-氨基-9-氧代吡咯并[[2,1- b ]喹唑啉-1-腈和类似的吡咯并[[1,2- a ]噻吩并[3,2- d ]嘧啶甲腈
摘要:
制备一系列2-烷硫基-4-氧代-3-喹唑啉乙腈4和2-烷硫基-4-氧代噻吩并[3,2 - d ]嘧啶-3-乙腈8。经氢化钠处理后,化合物4和8反应生成2-氨基-4,9-二氢-9-氧吡咯并[2,1- b ]喹唑啉-1-腈9和6-氨基-4,9-二氢-分别为9-氧吡咯并[1,2- a ]噻吩并[3,2 - d ]嘧啶-7-腈10。化合物4和8向三环氨基腈9和10的转化涉及二聚步骤,然后吡咯环化。用氢化钠处理后的叔丁酯衍生物4d和8d经过Thorpe-Ziegler环化反应,以提供作为主要产物的稠合的1,3-噻嗪的对氨基酯(分别为16和17)。
NaNO2/I2 as an alternative reagent for the synthesis of 1,2,3-benzotriazin-4(3H)-ones from 2-aminobenzamides
作者:Dinesh S. Barak、Sushobhan Mukhopadhyay、Dipak J. Dahatonde、Sanjay Batra
DOI:10.1016/j.tetlet.2018.12.025
日期:2019.1
An efficient transformation of 2-aminobenzamides to 1,2,3-benzotriazin-4(3H)-ones in the presence of sodium nitrite (NaNO2) and Iodine (I2) is described. The reaction is proposed to proceed via formation of nitrosyl halide that induces nitrosylation of the amino group of 2-aminobenzamide leading to diazotization followed by intramolecular cyclization.