Triethylamine (8.7 ml) was added to an ice-cooled suspension of 2-(2-triphenylmethylamino-4-thiazolyl)- 2-(Z-hydroxyimino)acetic acid (13 g) in 250 ml of anhydrous dichloromethane with stirring. The suspension turned to a clear, faint yellow solution. A solution of 2-furoyl chloride (3.3 g) in 20 ml of anhydrous dichloromethane was dropwise added under ice cooling, the resulting light brown solution was stirred at room temperature for one hour, the mixture was poured into 130 ml of ice-cooled 0.5N hydrochloric acid, and the formed crystals were collected by filtration and washed thrice with 30 ml dichloromethane, affording 5.2 g of the objective compound as colorless crystals.
