Acetic acid 4-chlorocarbonyl-2,6-dimethyl-phenyl ester → Acetic acid 4-(5,7-dimethoxy-1-methyl-4-oxo-1,4-dihydroquinazolin-2-yl)-2,6-dimethyl-phenyl ester

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Reaction Steps

A solution of 2,4-dimethoxy-6-methylamino-benzamide (0.28 g, 1.33 mmol) in pyridine (10 mL) was added to acetic acid 4-chlorocarbonyl-2,6-dimethyl-phenyl ester (1.1 eq.) and stirred at room temperature for 14 h. The solvent was removed and the reaction mixture was acidified with 1 N HCl and extracted with ethyl acetate. The solvent was removed and the crude was purified by silica gel column chromatography (40 g) employing 1% methanol in dichloromethane to give acetic acid 4-(5,7-dimethoxy-1-methyl-4-oxo-1,4-dihydro-quinazolin-2-yl)-2,6-dimethyl-phenyl ester (0.34 g, 67%). Acetic acid 4-(5,7-dimethoxy-1-methyl-4-oxo-1,4-dihydro-quinazolin-2-yl)-2,6-dimethyl-phenyl ester (0.34 g, 0.89 mmol) was dissolved in ethanol (5 mL), 5% aqueous NaOH solution (10 mL) was added dropwise and the mixture was stirred at room temperature for 1.5 h. The compound was extracted with ethyl acetate and washed with ether to give 2-(4-hydroxy-3,5-dimethylphenyl)-5,7-dimethoxy-1-methylquinazolin-4(1H-one (0.13 g, 43%). Selected data: MS (ES) m/z: 340.17; MP 188.5-189.1° C.

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