56844-12-3

56844-40-7

56844-12-3

General procedure for the synthesis of 4-chloro-6-bromothieno[2,3-d]pyrimidin-4(3H)-one from 6-bromothieno[2,3-d]pyrimidin-4(3H)-one: 6-bromothieno[2,3-d]pyrimidin-4(3H)-one (32.7 g, 142 mmol) was mixed with phosphorus triclosan (100 mL) and heated to reflux for 3 hours at 120 °C. Upon completion of the reaction, the reaction mixture was quenched by slowly pouring it into a mixture containing 5 M aqueous sodium hydroxide solution (1 L) and ice. Subsequently, the pH was adjusted with saturated aqueous sodium bicarbonate solution to 7. The precipitate formed was collected by filtration and washed with distilled water (3 x 200 mL). Drying gave 4-chloro-6-bromothieno[2,3-d]pyrimidine (31.0 g, 124 mmol, 88% yield) as a brown solid with a melting point of 112-118°C. Part of the product was further purified by silica gel column chromatography: the dried product was loaded onto the top of a pre-populated silica gel column and eluted with dichloromethane as the eluent, and the melting point of the purified product was 114-118 °C; the Rf value of thin-layer chromatography (dichloromethane/methanol, 98/2) was 0.67; 1H NMR (400 MHz, DMSO-d6) δ: 8.95 (s, 1H), and 7.89 (s, 1H); 13C NMR (100 MHz, DMSO-d6) δ: 168.9,153.2,152.5,130.2,122.9,118.5; infrared spectra (pure sample, cm-1): 3082,1508,1411,959,832,816,760; high-resolution mass spectrometry (EI, 70eV m/z): 247.8813 (calculated value C6H2BrClN2S, 247.8811, M+).1H NMR spectrum is in agreement with the literature41.13C NMR spectral data and reference melting point were not determined.