To a solution of (S)-1-(7-(4-chlorophenyl)-5-methylbenzo[d]thiazol-6-yl)ethane-1,2-diol (5H) (0.018 g, 0.056 mmol) in pyridine (0.5 mL)/dichloromethane (1 mL) was added trimethylacetyl chloride (0.010 mL, 0.081 mmol). Reaction mixture was stirred for 1 h at room temperature and additional trimethylacetyl chloride (0.020 ml 0.081 mmol) was added and left it overnight at room temperature. More trimethylacetyl chloride (0.030 ml, 0.242 mmol) was added to the mixture and stirred at room temperature for 30 min. Reaction mixture was diluted with ethyl acetate. Organic layer was washed with saturated sodium bicarbonate solution, dried (MgSO4), concentrated and purified by flash column chromatography (silica gel, 0 to 50% ethyl acetate/hexanes). LCMS-ESI+: calc'd for C21H22ClNO3S: 404.1 (M+H+). Found: 404.1 (M+H+).
