(S)-tert-butoxycarbonylamino-3-thiocarbamoyl-propionic acid benzyl ester → 2-(S)-tert-butoxycarbonylamino-3-thiazol-2-yl-propionic acid benzyl ester

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Reaction Steps

A 250 mL round bottom flask was charged with 2-(S)-tert-butoxycarbonylamino-3-thiocarbamoyl-propionic acid benzyl ester (1.0 g, 2.96 mmol), dimethoxyethane (66 mL), and bromoacetate diethylacetal (2.4 mL, 15.5 mmol). The flask containing the resulting mixture was fit with a reflux condenser and the mixture refluxed for 3 h. The resulting mixture was then concentrated in vacuo and the residue purified via flash silica gel chromatography (Analogix IF-280, SF65-400 g column, gradient 100:0-90:10 CH2Cl2:MeOH) to yield 2-(S)-tert-butoxycarbonylamino-3-thiazol-2-yl-propionic acid benzyl ester. 1H NMR (300 MHz, CDCl3) δ 7.67 (d, J=3.3 Hz, 1H), 7.29-7.44 (m, 5H), 7.20 (d, J=3.3 Hz, 1H), 5.15 (s, 2H), 5.75 (t, J=5.5 Hz, 1H), 73.15 (d, J=7.4 Hz, 1H), and 1.44 (s, 9H); MS (ES+) 363 (M+1).

Provenance & Evidence