Anthranilic Acid → 2-Ethyl-benzo[d][1,3]oxazin-4-one

Propanoyl chloride (6.2 g, 67 mmol) was added to a solution of anthranilic acid (1 g, 7.3 mmol) in dichloromethane (20 mL). The reaction medium was kept under reflux and agitation, with the end of the reaction being monitored by CG/MS. After the end of the reaction, a hydrochloric acid solution was added (20 mL, 1M), and the resulting mixture was extracted with ethyl acetate (100 mL), the extract was dried with magnesium sulfate and the solvent was evaporated. Acetic anhydride (15 mL) was added to the residue and the reaction medium was taken to reflux and accompanied through CG/MS in order to monitor cyclization. After the end of the reaction, the reaction medium spin dried at a temperature of 65° C. using portions of toluene to facilitate the elimination of the anhydride. 1.0 g of the raw product 2-ethyl-4H-3,1-benzoxazin-4-one was obtained, which was used directly in the stage subsequent to reaction.

1. temperatureunder reflux
2. customAfter the end of the reaction
3. extractionthe resulting mixture was extracted with ethyl acetate (100 mL)
4. dry with materialthe extract was dried with magnesium sulfate
5. customthe solvent was evaporated
6. additionAcetic anhydride (15 mL) was added to the residue
7. temperatureto reflux
8. customAfter the end of the reaction
9. customthe reaction medium spin dried at a temperature of 65° C.

ORD record

ord-1c23d2adda6a4cf9b35e41e6d8d31de7

Source dataset

uspto-grants-2014_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08735578B2