ethyl (3S)-3-aminobutanoate;hydrochloride

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Step 1 To a solution of 3-benzoyl-4-chloro-2-fluoro-benzaldehyde (Intermediate 10, 337 mg, 1.29 mmol) in dichloroethane (5 ml) was sequentially added (S)-3-amino-butyric acid ethyl ester hydrochloride (237 mg, 1.41 mmol), triethylamine (0.196 ml, 1.41 mmol), sodium triacetoxyborohydride (818 mg, 3.86 mmol) and glacial acetic acid (0.159 ml 2.57 mmol). The mixture was stirred for 2 days then dilute sodium bicarbonate was added. After stirring for 10 minutes, the mixture was extracted with ethyl acetate. The organic liquors were washed with water and brine, dried (MgSO4) and concentrated. The residue was purified by silica chromatography eluting with 20-100% ethyl acetate/petroleum ether furnishing (3S)-3-(3-benzoyl-4-chloro-2-fluoro-benzylamino)-butyric acid ethyl ester as a colourless oil (203 mg). MS: [M+H] 378 After stirring for 10 minutes the mixture was extracted with ethyl acetate The organic liquors were washed with water and brine dried (MgSO4) concentrated The residue was purified by silica chromatography eluting with 20-100% ethyl acetate/petroleum ether