Meldrum's acid (1.58 g, 10.96 mmol) was dissolved in trimethyl orthoformate (24.23 mL, 219 mmol) and the mixture was heated at 110° C. for 1 h. After cooling to RT, 4-[3-(methyloxy)phenyl]-2-thiophenamine (Description 40) (1.5 g, 7.31 mmol) was added to the mixture and reheated at 90° C. for 15 h. After cooling to RT, the mixture was evaporated in vacuo. The residue was dissolved in DCM and treated with potassium carbonate (3.03 g, 21.92 mmol). After stirring for 30 min, the mixture was filtered and the filtrate was evaporated in vacuo, to give the title compound (1.24 g). LCMS (A) m/z: 360 [M+1]+, Rt 1.19 min (acidic).
