Triethylamine → 3-{1-{2-{[2-(4-Tert-butylthiazol-2-yl)benzofuran-5-yloxy]methyl}phenoxy}butyl}-1,2,4-oxadiazoline-5-one

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Reaction Steps

2-{2-{[2-(4-tert-Butylthiazol-2-yl)benzofuran-5-yloxy]methyl}phenoxy}pentanamide oxime (240 mg) and triethylamine (61 mg) were dissolved in tetrahydrofuran (3 ml). To this solution was added a solution of ethyl chloroformate (65 mg) dissolved in tetrahydrofuran (1 ml) under ice-cooling. The reaction mixture was stirred for fifteen minutes, filtered, and concentrated. The resulting material was dissolved in xylene (4 ml) and 1.8-diazabicyclo[5.4.0]undec-7-ene (152 mg) was added. The mixture was stirred at 50° C. for three hours. The mixture was cooled, diluted with toluene, and washed successively with 0.5N hydrochloric acid and brine, and dried over magnesium sulfate. The crude material was purified on a silica gel column eluting with a mixed solvent of methylene chloride and methanol (1% vol.) to give partially purified product which was again purified on a silica gel column eluting with a mixed solvent of toluene and ethyl acetate (6:1) to give 3-{1-{2-{[2-(4-tert-butylthiazol-2-yl)benzofuran-5-yloxy]methyl}phenoxy}butyl}-1,2,4-oxadiazoline-5-one (120 mg).

Provenance & Evidence