Cycloaddition−Elimination Reactions of 5-Imino-1,2,4-thiadiazolidin-3-ones and 5-Imino-1,2,4-dithiazolidin-3-ones with Electron-Rich Double Bonds
作者:Franz Tittelbach、Siegfried Vieth、Matthias Schneider
DOI:10.1002/(sici)1099-0690(199803)1998:3<515::aid-ejoc515>3.0.co;2-6
日期:1998.3
5-Imino-1,2,4-thiadiazolidin-3-ones 1 react with compounds containing electron-rich double bonds such as enamines and ester enolates to afford the 2-iminothiazolidines 3, 4, and 10 in cycloaddition−elimination reactions. The less reactive 5-imino-1,2,4-dithiazolidin-3-ones 2 only give the 2-iminothiazolidines 3 or 4 with enamines; with ester enolates the 5-alkylidene-1,2,4-dithiazolidines 12 are formed
5-Imino-1,2,4-thiadiazolidin-3-ones 1 与含有富电子双键的化合物如烯胺和酯烯醇反应,在环加成消除反应中得到 2-亚氨基噻唑烷 3、4 和 10。反应性较低的 5-imino-1,2,4-dithiazolidin-3-ones 2 仅产生具有烯胺的 2-iminothiazolidines 3 或 4;与酯烯醇化物形成5-亚烷基-1,2,4-二噻唑烷12。与烯胺的反应产物进行水解和消除,形成相应的羟基化合物 5、6 或不饱和化合物 7、8,这取决于稠环的大小。