2,3,5,6-Tetrafluorophenol

50-01-1

54081-33-3

140-10-3

769-39-1

6340-72-3

Chalcone 1d (1.0 g, 3.4 mmol) was added to a 10 mL DMF solution containing guanidine hydrochloride (0.64 g, 6.7 mmol) and sodium hydride (0.32 g, 13.4 mmol). The reaction mixture was stirred at 50 °C for 1.5 h before being cooled to room temperature and subsequently poured into ice water and extracted with ethyl acetate. Undissolved material at the phase boundary was removed by filtration, resulting in the isolation of 2-amino-6-phenyl-5,6-dihydropyrimidin-4(1H)-one (7a, 0.1 g, 16% yield). The 1H NMR data and melting point (255-257 °C; literature value 257.3 °C [19]) of this product were in agreement with those reported in the literature [19]. The extract was washed with water and dried with CaCl2 and concentrated under reduced pressure to remove the solvent, yielding 0.29 g of residue, which was analyzed by NMR and GC/MS.