Synthesis and Crystal Structure of 4-tert-Butyl-2(3H)-oxazolethione

摘要

One of the most generally useful reagents for the cyclization of omega hydroxy carboxylic acids to macrocyclic lactones is 2,2'-bis(4-tert-butyl-1-isopropylimidazolyl) disulfide. During attempts to synthesize an analogous polymer-supported bis(imidazolyl) disulfide via 4-tert-butyl-2-mercaptoimidazole (1), we obtained 4-tert-butyl-2(3H)-oxazolethione (3) instead. Our synthetic method was analogous to that for 4-tert-butyl-1-isopropyl-2-mercaptoimidazole (2). Treatment of 1-bromopinacolone with an excess of ammonia (instead of isopropylamine) followed by evaporation of the ammonia and treatment with KSCN in 1 M HC1 in 50/50 v/v ethanol/water gave 3. Oxidation of 3 with MnO2 gave 2,2'-bis(4-tert-butyl-oxazolyl) disulfide (4).