Nonacidic and Highly Chemoselective Protection of the Carbonyl Function. 3-Methylbenzothiazolines as a Base- and Acid-Resistant Protected Form for the Carbonyl Groups
groups by conversion into 3-methylbenzothiazoline derivatives with o-(methylamino)benzenethiol was described. With this method, 3-methylbenzothiazolines were conveniently obtained in excellent yields from various aldehydes and ketones. This method allows efficient protection and deprotection under mild and neutral conditions and affords protection of the carbonyl group against both basic and acidic conditions
Core electron binding energies of 3-substituted 2-nitrosoimino-2,3-dihydrobenzothiazoles (1) and related compounds were measured by ESCA to show large contribution of mesoionic structures for 1 and this was also supported by observed chemical shifts (NMR) of 3-methyl groups of benzothiazolines.