Triacetoxyperiodinane → 1-(3-Oxo-propyl)-3-(4-trifluoromethyl-phenyl)-1,4,6,7-tetrahydro-pyrazolo[4,3-c]pyridine-5-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

Dess-Martin periodinane (1.43 g, 3.36 mmol) was added portion wise to a stirred solution of 1-(3-hydroxy-propyl)-3-(4-trifluoromethyl-phenyl)-1,4,6,7-tetrahydropyrazolo[4,3-c]pyridine-5-carboxylic acid tert-butyl ester (1.30 g, 3.05 mmol) in CH2Cl2 (15 mL) at 0° C. under N2. Then the reaction was stirred at 0° C. for 15 min and allowed to warm to room temperature. After stirring at room temperature for 1.5 h the reaction was diluted with Et2O (50 mL) and saturated NaHCO3 (15 mL) was added slowly (caution! gas evolution). Then Na2S2O3.5H2O (5.31 g, 21.4 mmol) was added and stirred for 30 min. The layers were separated and the aqueous layer was extracted with Et2O (2×30 mL). The combined extracts were washed with brine, dried (Na2SO4) and concentrated. MPLC (1-10% MeOH/CH2Cl2) afforded the aldehyde in 79% yield (1.02 g). TLC (silica, 10% MeOH/CH2Cl2): Rf=0.67. MS (electrospray) calculated for C21H24F3N3O3, 424.2 ([M+H]+), m/z found, 424.2. 1H NMR (400 MHz, CDCl3): 9.82 (s, 1H), 7.65 (br d, J=8.0 Hz, 2H), 7.54 (br s, 2H), 4.53 (s, 2H), 4.21 (t, J=6.2 Hz, 2H), 3.68 (br s, 2H), 3.04 (t, J=6.2 Hz, 2H), 2.70 (t, J=5.6 Hz, 2H), 1.39 (s, 9H).

Provenance & Evidence