Sulfuric Acid → {2-[2-(3-Chloro-phenyl)-3-cyclopentyl-propionylamino]-thiazol-4-yl}-acetic acid methyl ester

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Reaction Steps

A solution of {2-[2-(3-chloro-phenyl)-3-cyclopentyl-propionylamino]-thiazol-4-yl}-acetic acid ethyl ester (prepared as in Example 28A, 177.2 mg, 0.42 mmol) in methanol (15 mL) was treated with a catalytic amount of sulfuric acid. The reaction mixture was heated under reflux for 40 h. The reaction was then concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 230-400 mesh, 70/30 hexanes/ethyl acetate) afforded {2-[2-(3-chloro-phenyl)-3-cyclopentyl-propionylamino]-thiazol-4-yl}-acetic acid methyl ester (104.4 mg, 60.9%) as a clear oil: EI-HRMS m/e calcd for C20H23ClN2O3S (M+) 406.1117, found 406.1118.

Provenance & Evidence