Formamide → 6,7-Dimethoxy-4-methylquinazoline

Reaction equation

[CH3:1][C:2]([C:4]1[C:9]([NH2:10])=[CH:8][C:7]([O:11][CH3:12])=[C:6]([O:13][CH3:14])[CH:5]=1)=O.B(F)(F)F.CCOCC.[CH:24]([NH2:26])=O>>[CH3:1][C:2]1[C:4]2[C:9](=[CH:8][C:7]([O:11][CH3:12])=[C:6]([O:13][CH3:14])[CH:5]=2)[N:10]=[CH:24][N:26]=1

Participants

Reactant 3

HCID 713Formamide

HCID 8000Boron trifluoride etherate

HCID 602085Ethanone, 1-(2-amino-4,5-dimethoxyphenyl)-

Product 1

HCID 43194226,7-Dimethoxy-4-methylquinazoline

Procedure

2-Amino-4,5-dimethoxyacetophenone (5.0 g) and boron trifluoride etherate (1.5 mL) were heated in formamide (80 mL) at 140° C. for 18 h. The reaction mixture was cooled to room temperature and extracted three times with benzene. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under vacuum. Flash chromatography on silical gel, eluting with a mixture of 98/2 dichloromethane/methanol gave 4-methyl-6,7-dimethoxyquinazoline (D-1) as a yellow solid, 3.43 g; 1H NMR (CDCl3, 300 MHz) 8.99 (s, 1H), 7.30 (s, 1H), 7.18 (s, 1H), 4.05 (s, 6H), 2.87 (s, 1H) ppm; MS (ES) 205 (M+H).