Trifluoroacetic acid → 1-[1-[3-(4-Benzo[d]isoxazol-3-yl-piperazin-1-yl)-2-hydroxy-propyl]-3-(4-trifluoromethyl-phenyl)-1,4,6,7-tetrahydro-pyrazolo[4,3-c]pyridin-5-yl]-ethanone

Participants

Reaction Conditions

Reaction Steps

A solution of 82 mg (0.27 mmol) of 4-benzo[d]isoxazol-3-yl-piperazine-1-carboxylic acid tert-butyl ester in 2 mL of CH2Cl2 was treated with trifluoroacetic acid (0.5 mL) at room temperature overnight. The solvent was then removed and the crude product dissolved in EtOH and stirred over 100 mg of sodium bicarbonate for 1 h, the solid was then filtered off and the filtrate concentrated. The crude piperazine was then dissolved in 4 mL EtOH and treated with 100 mg (0.27 mmol) of 1-[1-oxiranylmethyl-3-(4-trifluoromethyl-phenyl)-1,4,6,7-tetrahydro-pyrazolo[4,3-c]pyridin-5-yl]-ethanone. The solution was heated to 60° C. overnight. The solvent was then removed by rotary evaporation and the crude product was purified by column chromatography (silica, 0-10% MeOH/EtOAc) to afford 105 mg (68%) of a white solid. MS (electrospray), exact mass calculated for C29H31F3N6O3, 568.24; m/z found, 569.2 [M+H]+. 1H NMR (CDCl3, 400 MHz, a mixture of amide rotamers): 7.77 (d, J=8.41 Hz, 1H), 7.69 (m, 2H), 7.67-7.62 (m, 2H), 7.50-7.44 (m, 1H), 7.45-7.42 (m, 1H), 7.23-7.18 (m, 1H), 4.93 (br m, 1H), 4.87 and 4.75 (A and B of AB quartet, J=15.65 Hz, 1H), 4.65 (br s, 1H), 4.27-4.15 (m, 2.3H), 4.09-3.95 (m, 1.7H), 3.91-3.82 (m, 0.7H), 3.81-3.66 (m, 1.3H), 3.62-3.49 (m, 4H), 3.01-2.85 (m, 1.5H), 2.85-2.74 (m, 2.5H), 2.71-2.60 (m, 2H), 2.58-2.45 (m, 2H), 2.20 (s, 1.5H), 2.15 (s, 1.5H).

Provenance & Evidence