Formaldehyde → N-((1-(2-chlorophenyl)-3-(trifluoromethyl)-1H-pyrazol-5-yl)methyl)-N-methyl-3'-(methylsulfonyl)biphenyl-4-amine

Participants

Reaction Steps

Into an 8 mL vial was weighed 215 mg of N-((1-(2-chlorophenyl)-3-(trifluoromethyl)-1H-pyrazol-5-yl)methyl)-3′-(methylsulfonyl)biphenyl-4-amine (0.42 mmol). Addition of 2 mL of methanol followed by 0.5 mL of acetic acid, and 150 μL of 37% aqueous formaldehyde solution afforded a solution that was treated with 40 mg of sodium cyanoborohydride (0.64 mmol). After 30 min. at room temperature the reaction was quenched by the addition of 6N HCl (aq.). After gas evolution had subsided, the reaction mixture was diluted with EtOAc and the aqueous was made basic by the addition of saturated aqueous NaHCO3. The basic aqueous was extracted with EtOAc (3×) and the combined organic extracts were washed with brine, dried (Na2SO4), filtered, and concentrated in vacuo to afford a colorless film. The crude product was purified by silica gel flash chromatography on a 12 g column using gradient elution from 0% to 100% EtOAc/hexane. Appropriate fractions were combined and concentrated in vacuo to afford N-((1-(2-chlorophenyl)-3-(trifluoromethyl)-1H-pyrazol-5-yl)methyl)-N-methyl-3′-(methylsulfonyl)biphenyl-4-amine as a colorless film. This material was impure by NMR analysis and was further purified by preparative reverse phase HPLC eluting with a gradient from 30% to 100% MeCN in H2O (each with 0.05% trifluoroacetic acid). The appropriate fractions were made basic by addition of saturated aqueous NaHCO3 solution and concentrated in vacuo to remove most of the acetonitrile. The resulting basic aqueous was extracted with CH2Cl2 (4×). The combined organic extracts were dried (Na2SO4), filtered and concentrated in vacuo to afford N-((1-(2-chlorophenyl)-3-(trifluoromethyl)-1H-pyrazol-5-yl)methyl)-N-methyl-3′-(methylsulfonyl)biphenyl-4-amine as a brittle foam that was broken up into a white powder, yield 126 mg (57% yield): 1H NMR (400 MHz, CDCl3): δ 8.11-8.08 (m, 1H, 7.84-7.79 (m, 2H, 7.62-7.56 (m, 2H, 7.52-7.40 (m, 5H), 6.72-6.67 (m, 2H), 6.52 (s, 1H), 4.43 (br s, 1H), 3.09 (s, 3H), 2.94 (S, 3H); MS (ESI) m/z 520.3 [M+H]+.

Provenance & Evidence