3-azetidinecarboxylic Acid → 1-(4-(5-(1-(pyridin-2-yl)-5-(trifluoromethyl)-1H-pyrazol-4-yl)-1,2,4-oxadiazol-3-yl)benzyl)azetidine-3-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

A solution of 4-(5-(1-(pyridin-2-yl)-5-(trifluoromethyl)-1H-pyrazol-4-yl)-1,2,4-oxadiazol-3-yl)benzaldehyde (21 g, 54.5 mmol) and azetidine-3-carboxylic acid (6.61 g, 65.4 mmol) in ethanol (750 mL) and acetic acid (20 mL) was stirred at RT for 30 min. The reaction was cooled to 0° C. and a solution of sodium cyanoborohydride (caution: potential source of cyanide generation) (1.17 g, 27.3 mmol) in ethanol was added slowly. The reaction was warmed to RT and stirred overnight. The reaction mixture was concentrated under reduced pressure and the residue was diluted with water. The solids were collected by filtration and washed with water. The product was purified by triturating once each with DCM:methanol (98:2), DCM:methanol (96:4) and ethyl acetate to afford 1-(4-(5-(1-(pyridin-2-yl)-5-(trifluoromethyl)-1H-pyrazol-4-yl)-1,2,4-oxadiazol-3-yl)benzyl)azetidine-3-carboxylic acid (16 g, 34 mmol). The compound had an HPLC retention time=8.48 min.−Column: XbridgeA 4.6×150 mm Flow rate=1.0 mL/min. Buffer=0.05% TFA in water pH2.5. Solvent A=Buffer:Acetonitrile (95:5), Solvent B=Acetonitrile:Buffer (95:5). 0-100% B over 12 minutes. LC/MS M+1=471.2.

Provenance & Evidence