Acetic Acid → 2-(4-hydroxy-3-(2-hydroxyethyl)phenyl)-5,7-dimethoxyquinazolin-4(3H)-one

A mixture of 2-amino-4,6-dimethoxy-benzamide (0.25 g, 1.27 mmol), 3-(2-hydroxy-ethyl)-4-methoxymethoxy-benzaldehyde (0.268 g, 1.27 mmol), sodium hydrogensulfite (0.146 g, 1:4 mmol) and p-toluenesulfonic acid (0.025 g, 0.127 mmol) in N,N-dimethyl acetamide (8 mL) was stirred at 150° C. overnight under nitrogen atmosphere. The reaction mixture was cooled to room temperature, the solvent evaporated under reduced pressure. Water (70 mL) was added to obtain a solid. The yellow solid was filtered off, washed with water and dried under vacuum to provide crude 2-[3-(2-hydroxy-ethyl)-4-methoxymethoxy-phenyl]-5,7-dimethoxy-3H-quinazolin-4-one (0.182 g, 36.7%) which was used as such in the next step. A solution of 2-[3-(2-hydroxy-ethyl)-4-methoxymethoxy-phenyl]-5,7-dimethoxy-3H-quinazolin-4-one (0.18 g), 50% acetic acid solution (4 mL) and catalytic amount of concentrated sulfuric acid (0.02 mL) was heated at 70° C. for 2.5 h. After cooling to room temperature the reaction mixture was diluted with water (30 mL) to obtain a solid. The solid was filtered off, washed with water and dried under high vacuum to provide crude solid (0.135 g, 85%). The crude was purified by flash column chromatography to give pure 2-(4-hydroxy-3-(2-hydroxyethyl)phenyl)-5,7-dimethoxyquinazolin-4(3H)-one (0.035 g. 8% over 2 steps). Selected data: MS (ES) m/z: 343.0; MP 249-250.3° C.