Sodium cyanoborohydride → 3-Bromo-N-[(2S)-4-[3-(4-butyrylpiperazin-1-yl)azetidin-1-yl]-2-(4-fluorophenyl)butyl]-N-methyl-5-(trifluoromethyl)benzamide dihydrochloride

Participants

Reaction Steps

To a solution of 3-bromo-N-[(2S)-2-(4-fluorophenyl)-4-oxobutyl]-N-methyl-5-(trifluoromethyl)benzamide (see Method 3; 450 mg, 1.0 mmol) and 1-azetidin-3-yl-4-(cyclopropylcarbonyl)piperazine (see Method 15; ˜0.9 mmol) in methanol (50 mL) was added a solution of sodium cyano borohydride (250 mg, 4.0 mmol) and zinc chloride (270 mg, 2.0 mmol) in methanol (30 mL). The reaction mixture was stiffed at RT for 15 min and then the solvent was removed by evaporation. The residue was partitioned between ethyl acetate (50 mL) and water (20 mL). The organic solution was washed with brine and then dried over Na2SO4. The solvent was removed by evaporation and the residue was dissolved in ethyl acetate. The product was purified by means of silica gel chromatography first eluting with ethyl acetate and then with a mixture of ethyl acetate, methanol and triethylamine (9:1:1). The proper fractions were combined and concentrated on a rotavapor then the residue was co-evaporated twice using methylene chloride. The residue was dissolved in methylene chloride and to the solution was added HCl-saturated diethyl ether (1 mL). The solvent was removed by evaporation and then, the residue was co-evaporated twice with methylene chloride. There was obtained 220 mg (30%) of the title compound. 1H NMR (400 MHz, CD3OD): 0.8-1.0 (t, 3H), 1.5-1.6 (qt, 2H), 1.8-2.2 (cm, 3H), 2.4 (t, 2H), 2.6-4.6 (cm, 20H), 7.0-7.6 (cm, 6H), 7.9 (d, 1H); LCMS: m/z 642 (M+1)+.

Provenance & Evidence