7-Methylthieno[3,2-d]pyrimidin-4(3H)-one

Preparation

7-Methylthieno[3,2-d]pyrimidin-4(3H)-one was prepared using methyl 3-amino-4-methylthiophene-2-carboxylate 25 (171 mg, 1.0 mmol) according to the procedure described for 7d as a white solid (100 mg, 60% yield), mp 244-246 °C.
1 H NMR (400 MHz; DMSO-d6; TMS) δ 12.51 (s, 1H), 8.18 (s, 1H), 7.84 (s, 1H), 2.32 (s, 3H). ESI-MS: m/z 167.0 [M + H]+ . HPLC flow rate 1 mL/min, tR (acetonitrile/water 65:35) = 6.2 min, purity 95%.