[Cl:1][C:2]1[CH:11]=[CH:10][C:5]([C:6]([NH:8][NH2:9])=[O:7])=[C:4]([OH:12])[CH:3]=1.[CH2:13](OC(OCC)OCC)C>>[Cl:1][C:2]1[CH:11]=[CH:10][C:5]([C:6]2[O:7][CH:13]=[N:9][N:8]=2)=[C:4]([OH:12])[CH:3]=1A mixture of 4-chloro-2-hydroxybenzoic acid hydrazide (Chemical Abstracts, 93:7808, 475 mg, 2.55 mmol) and triethylorthoformate. (3.6 ml) is heated at 130° C. for 3.5 hours. After cooling, a precipitate formed and is collected by filtration. The filter cake is recrystallized from methanol to give 173 mg (35%) of 5-chloro-2-(1,3,4-oxadiazol-2-yl)phenol. This phenolic product is reacted with (2S)-glycidyl 3-nitrobenzenesulfonate substantially as described for Epoxide 1 to yield 170 mg (69%) of the title epoxide.
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