Salicylamide → 2,2-dibutyl-4-oxo-2,3-dihydro-4H-1,3-benzoxazine

Reaction equation

[CH2:1]([C:5]([CH2:7][CH2:8][CH2:9][CH3:10])=[O:6])[CH2:2][CH2:3][CH3:4].[C:11]([NH2:20])(=[O:19])[C:12]1[C:13](=[CH:15][CH:16]=[CH:17][CH:18]=1)O.O.C1(C)C=CC(S(O)(=O)=O)=CC=1>C1(C)C=CC=CC=1>[CH2:1]([C:5]1([CH2:7][CH2:8][CH2:9][CH3:10])[NH:20][C:11](=[O:19])[C:12]2[CH:13]=[CH:15][CH:16]=[CH:17][C:18]=2[O:6]1)[CH2:2][CH2:3][CH3:4]

Participants

Procedure

A mixture of 20 g of dibutylketone, 19.3 g of salicylamide and 2.7 g of p-toluenesulfonic acid monohydrate is added to 300 ml of toluene and the mixture is refluxed overnight by making use of a dehydrator of Dean Stark. After cooling, the reaction mixture is washed, dried and evaporated to remove the solvent. The residue is purified by silica gel column chromatography (solvent; hexane:ethyl acetate=95:5) to obtain 34 g of 2,2-dibutyl-4-oxo-2,3-dihydro-4H-1,3-benzoxazine as a yellow oil.