(Methoxycarbonylsulfamoyl)triethylammonium hydroxide → 3-(5-chloromethyl-[1,3,4]oxadiazol-2-yl)-1-cyclohexylmethyl-7-methoxy-1H-indole

To a solution of 1-cyclohexylmethyl-7-methoxy-1H-indole-3-carboxylic acid N′-(2-chloroacetyl)hydrazide (250 mg, 0.662 mmol) in tetrahydrofuran (3 ml) was added (methoxycarbonylsulfamoyl)triethylammonium hydroxide, inner salt (315 mg, 1.32 mmol) and the resulting reaction mixture subjected to microwave irradiation at 150° C. for 15 minutes. The reaction mixture was quenched with methanol and the solvent evaporated. The resulting residue was purified by flash chromatography using 33-50% (v/v) ethyl acetate in heptane to give 3-(5-chloromethyl-[1,3,4]oxadiazol-2-yl)-1-cyclohexylmethyl-7-methoxy-1H-indole (169 mg, 0.47 mmol) as a yellow solid. This reaction was repeated on a 0.53 mmol scale to afford the same intermediate (a total of 276 mg, 0.77 mmol).