Ammonium Chloride → 2-{(S)-3-(4-amino-phenyl)-2-[(R)-4-(4-methoxy-phenyl)-2,5-dioxo-imidazolidin-1-yl]-propionylamino}-thiazole-4-carboxylic acid methyl ester

Participants

Reaction Steps

To a stirred solution of 2-[(S)-2-[(R)-4-(4-methoxy-phenyl)-2,5-dioxo-imidazolidin-1-yl]-3-(4-nitro-phenyl)-propionylamino]-thiazole-4-carboxylic acid methyl ester (0.32 g, 0.59 mmol) in methanol (125 mL), tetrahydrofuran (25 mL) and N,N-dimethylformamide (3 mL) was added a solution of ammonium chloride (0.63 g, 11.8 mmol) in water (3 mL) followed by zinc dust (<10 μM particle size) (0.388 g, 5.94 mmol). After 15 minutes the reaction mixture was filitered through a pad of Celite® and washed through with methanol. The filtrate was concentrated in vacuo and the residue partitioned between dichloromethane and water. The organic solution was washed with saturated aqueous sodium bicarbonate, water, brine, dried over sodium sulfate and concentrated in vacuo to a yellow solid (0.35 g). Purification by chromatography using silica eluted with 90:10:6:5 chloroform/water/acetic acid/methanol followed by drying in vacuo gave 2-{(S)-3-(4-amino-phenyl)-2-[(R)-4-(4-methoxy-phenyl)-2,5-dioxo-imidazolidin-1-yl]-propionylamino}-thiazole-4-carboxylic acid methyl ester as a brown solid (66 mg, 22%).

Provenance & Evidence