Cesium carbonate → HCID 178440171, compound

Participants

Reaction Steps

Methyl 2-propyl-4-[2-(1-oxo-2,2,2-trifluoroethyl)-1H-pyrrol-1-yl]imidazole-5-carboxylate (15 g, 0.046 mol) from Example 6 was dissolved in DMF (500 mL) and Cs2CO3 (32.9 g, 0.1 mol) added. After 5 minutes, N-triphenylmethyl-5-[4'-(bromomethyl)biphenyl-2-yl]tetrazole (Example 12, 26.9 g, 0.048 mol) was added and the reaction mixture stirred at room temperature for 6 hours. The reaction was filtered to remove insoluble salts and the DMF removed high vacuum. The residue was partitioned between ethyl acetate (150 mL) and water (50 mL). The organic layer was extracted with brine, dried over anhydrous magnesium sulfate, and the solvent evaporated under reduced pressure. Chromatography of the residue on silica gel, eluting with a gradient of ethyl acetate/hexane (1:4) to ethyl acetate/hexane (1:1) afforded 25 g of the title compound in its triphenylmethyl-protected form. The triphenylmethyl protecting group was removed by refluxing in methanol (280 mL) containing 10% aqueous citric acid (28 mL) for 4 hours. The reaction mixture was diluted with water (100 mL) and the milky solution extracted with several times with hexane. The aqueous layer was extracted with ethyl acetate and the combined organic layers extracted with brine. The organic layer was dried over anhydrous magnesium sulfate and the solvent removed under reduced pressure. The residue was recrystallized using Hexane/ethyl acetate (1:1) to afford 13.4 g of the title compound. MS (FAB, thioglycerol) 564(M+1), mp 135°-137° C.

Provenance & Evidence