Chloride → 2H-1,2-Benzoxazin-3(4H)-one

Participants

Reaction Steps

Into 50 mL methylene chloride was dissolved 0.682 g (2 mmol) of the above intermediate terephthalic acid, followed by 5 drops DMF and 3.88 mL (48 mmol) triethylamine. The mixture was cooled in an ice bath, and 0.42 mL (4.8 mmol) oxayl chloride was added in one portion. After 30 min 10 mL MeOH was added and ice bath was removed. After stirring an additional 30 min, the mixture was shaken between EtOAc (100 mL) and cold dilute HCl (100 mL). The organic layer was washed with satd NaHCO3 (100 mL), dried (MgSO4), and evaporated. Crystalline desired benzoxazinone (456 g, 66%) was obtained from a concentrated methylene chloride-hexane solution.

Provenance & Evidence