Ethyl chloroformate → (2-Tert-butoxycarbonylamino-thiazol-5-yl)-propynoic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

(5-Ethynyl-thiazol-2-yl)-carbamic acid tert-butyl ester (1.2 g, 5.350 mMol) was dissolved in THF (25 ml) in inert atmosphere and stirred at −78° C., nBuLi (7.4 ml, 1.6 M solution in hexane, 11.848 mMol) was added drop wise. After complete addition the reaction was stirred for 0.5 hr. followed by addition of ethyl chloroformate (0.775 g, 7.141 mMol) at −78° C. Reaction was allowed to come to 0° C. and quenched with water (50 ml) and extracted with ethyl acetate (25 ml×3). The organic layer was washed with brine, dried over anhydrous sodium sulfate and concentrated under reduced pressure to get (2-tert-butoxycarbonylamino-thiazol-5-yl)-propynoic acid ethyl ester (1.4 g).

Provenance & Evidence