Pyridine → 5-(4-{2-[5-Methyl-2-(4-trifluoromethyl-phenyl)-thiazol-4-yl]-ethoxy}-phenyl)-3H-[1,3,4]oxadiazol-2-one

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Reaction Steps

To a suspension of: 4-{2-[5-Methyl-2-(4-trifluoromethyl-phenyl)-thiazol-4-yl]-ethoxy}-benzoic acid hydrazide (Example 4, 276 mg, 0.65 mmol) in dichloromethane (4 mL) add pyridine (104 μL, 1.3 mmol) followed by phenylchloroformate (0.88 μL, 0.71 mmol). Stir the resulting mixture at room temperature until all the starting material is consumed (by TLC analysis). Dilute the mixture with ethyl acetate wash with water then brine dry over MgSO4 and concentrate under reduced pressure. Take the residue up in acetonitrile (5 mL). To this mixture, add DBU (106 μL, 0.71 mmol). Seal the resulting solution; warm it to 170° C. in a Personal Chemistry™ microwave oven and stir at this temperature for 120 min. Cool the reaction to room temperature, dilute with ethyl acetate, wash with 1 M HCl solution (or saturated NaH2PO4 solution) dry over MgSO4 and concentrate. Triturate the resulting residue with dichloromethane several times to give the title compound as a tan solid (137 mg). (recrystallized from ethyl acetate in a sealed tube at 140° C.).

Provenance & Evidence