4-[2-(N'-{3-[5-(4-Methoxy-phenyl)-oxazol-2-yl]-benzoyl}-hydrazino)-2-oxo-ethyl]-benzoic Acid Methyl Ester → 4-(5-{3-[5-(4-Methoxy-phenyl)-oxazol-2-yl]-phenyl}-[1,3,4]oxadiazol-2-ylmethyl)-benzoic Acid Methyl Ester

Participants

Reaction Steps

0.24 g (0.49 mmol) of 4-[2-(N′-{3-[5-(4-Methoxy-phenyl)-oxazol-2-yl]-benzoyl}-hydrazino)-2-oxo-ethyl]-benzoic acid methyl ester from Preparation 8 was dissolved in about 10 mL of poly phosphoric acid. The mixture was stirred at 90–100° C. for 1 hour before allowing to cool to room temperature. Water was added and the product was extracted with 1:1:1 EtOAC/THF/Et2O (2×). The extracts were combined and washed with saturated aqueous NaCl solution then dried MgSO4. Slurried solid product in hot EtOAc and filtered. Dried in vacuum oven overnight at 70° C. to obtain 0.13 g (57%) desired product.

Provenance & Evidence