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