To a solution of 6-(5-methyl-3-phenyl-isoxazol-4-ylmethoxy)-nicotinic acid (500 mg, 1.6 mmol) in DMF (10 mL) were added 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (569 mg, 1.8 mmol), N,N-diisopropyl ethyl amine (1.38 mL, 8.1 mmol) and 5,6,7,8-tetrahydro-(1,2,4)triazolo(4,3-a)-pyrazine hydrochloride (1.8 mmol). The resulting reaction mixture was stirred overnight at room temperature. Concentration and purification by chromatography (SiO2, heptane:ethyl acetate=100:0 to 1:1 and then dichloromethane:methanol=9:1) afforded the title compound (605 mg, 86%) which was obtained as a white foam. MS: m/e=417.4 [M+H]+.
