Pyrido[3,4-d]pyrimidin-4(3H)-one (8CI,9CI)

3473-63-0

7579-20-6

19178-25-7

3-Aminoisonicotinic acid (691 mg, 5.0 mmol), formamidine acetate (573 mg, 5.5 mmol) and anhydrous ethanol (10 mL) were added to a Biotage microwave reactor tube. The reaction mixture was placed in a microwave reactor and heated at 160 °C for 30 min. After completion of the reaction, the reaction solution was diluted with deionized water (20 mL) and cooled to 0 °C in an ice bath. The resulting suspension was extracted and the filter cake was washed with ice-cooled deionized water (10 mL) to afford quinazoline A2 (259 mg, 35% yield) in white solid form. The product was analyzed by LC-MS showing purity >98% (m/z = 148.0 [M + H]+, retention time Rt = 0.604 min).