Formaldehyde → 6-Methoxy-1-phenyl-1,2-dihydro-4H-3,1-benzoxazin-4-one
Reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[CH:5][C:6]([NH:12][C:13]2[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=2)=[C:7]([CH:11]=1)[C:8]([OH:10])=[O:9].[CH2:19]=O>C(O)C>[CH3:1][O:2][C:3]1[CH:4]=[CH:5][C:6]2[N:12]([C:13]3[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=3)[CH2:19][O:9][C:8](=[O:10])[C:7]=2[CH:11]=1Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
A mixture of 15.0 g (0.062 mole) of 5-methoxy-2-(phenylamino)benzoic acid and 75 ml of 37% aqueous formaldehyde solution in 75 ml of ethanol was heated on the steam bath for 75 minutes. The mixture was cooled and added to 400 g ice/water. The crude oxazine product was filtered, stirred in 75 ml of 5% aqueous sodium bicarbonate, and refiltered to yield 13.0 g (83% yield) of the product, mp 99.5°-101° C. A sample recrystallized from hexane was analytically pure, mp 100°-102° C.