Acetic Acid → methyl[3-((2R)-2-{[(1R)-1-phenyl-ethyl]-amino}-propyl)-phenyl]-acetate

Participants

Reaction Steps

A solution of methyl [3-(2-oxopropyl)phenyl]acetate (Preparation 90) (45.3 g, 236 mmol), (R)-α-methyl benzylamine (27.6 ml, 214 mmol), sodium triacetoxyborohydride (68.1 g, 321 mmol) and acetic acid (14.7 ml, 257 mmol) in dichloromethane (1500 ml) was stirred at room temperature for 18 hours. The reaction mixture was quenched by addition of saturated aqueous sodium bicarbonate (600 ml) and allowed to stir until effervescence ceased. The organic phase was separated and the aqueous phase extracted with further dichloromethane (2×100 ml). The combined organic extracts were washed with brine (100 ml), dried (sodium sulfate), filtered through celite and reduced in vacuo. The oil was dissolved in methanol (200 ml), treated with 1M hydrogen chloride in methanol (300 ml) and reduced in vacuo to give a 4:1 mixture of diastereomers (R,R major) as an off-white, hydrochloride salt. Two successive crystallisations (diisopropylether/methanol) gave the title compound (27.3 g) as a colourless crystalline solid.

Provenance & Evidence