作者:S. Rajappa、R. Sreenivasan
DOI:10.1016/0040-4020(80)88036-7
日期:1980.1
A novel intramolecular oxidative cyclization of the 3,4-diaminophenyl thiourea (3) to the 5,6-diaminobenzthiazole (4) is reported. This conversion can be brought about by Pd/C in presence of atmospheric oxygen in acid solution. It is likely that the quinone-imine (5) is an intermediate in this transformation. Surprisingly catalytic reduction (Pd/C, H2) of the 4-amino-3-nitrophenyl thiourea (2) gave
报道了3,4-二氨基苯基硫脲(3)到5,6-二氨基苯并噻唑(4)的新型分子内氧化环化。该转化可以通过Pd / C在大气氧在酸性溶液中的存在下实现。醌-亚胺(5)很可能是该转化的中间体。令人惊讶地催化还原(的Pd / C,H 2将4-氨基-3-硝基苯基硫脲)(2),得到两个3和4。描述了一种合理的“一锅”还原氧化顺序(铁/酸,氯化铁),用于从相应的4-氨基-3-硝基苯基硫脲制备这种和其他此类5,6-二氨基苯并噻唑。