Ethyl 4-chloroacetoacetate → 2-(2,6-Dihydroxyphenyl)-4-thiazoleacetic Acid Ethyl Ester

Participants

Reaction Steps

The procedure used for the preparation of 4a was repeated with 2,6-dihydroxybenzenecarbothioamide 3b (1.02 g, 6.04 mmol), ethyl 4-chloroacetoacetate (1.99 g, 12.1 mmol), and LiBr (525 mg, 6.04 mmol) in dry THF (15 mL) to give 4b (1.16 g, 69%) as a white solid after chromatographic purification on silica gel (gradient EtOAc/CH2Cl2 : 0-12%) and recrystallization from EtOAc/hexane. mp 152.5°-154.0° C.; IR (KBr) 3256 (br), 1742, 1460, 1157 cm-1 ; 1H NMR (DMSO-d6) δ 1.17 (3H, t, J=7.2 Hz, CH3), 3.88 (2H, s, CH2), 4.08 (2H, q, J=7.2 Hz, CH2), 6.44 (2H, d, J=8.2 Hz, Ar), 7.09 (1H, t, J=8.2 Hz, Ar), 7.51 (1H, s), 12.19 (2H, s, OH); FDMS m/z 279 (M+); Anal. Calcd for C13H13NO4S: C, 55.90; H, 4.69; N, 5.01. Found: C, 56.19; H, 4.85; N, 4.86.

Provenance & Evidence