A mixture of potassium carbonate (450 mg), bromocyclopropane (394 mg) and 4-(2,2-dioxido-3,4-dihydropyrido[2,1-c][1,2,4]thiadiazin-9-yl)phenol (300 mg) in DMSO (3 mL) was stirred at 130° C. overnight. Then bromocyclopropane (788 mg) and sodium iodide (488 mg) were added and the mixture was stirred at 150° C. for 5 hr. The mixture was poured into 1N NaOH aq. and extracted with EtOAc. The organic layer was separated, washed with 1N NaOH aq. and brine, dried over anhydrous magnesium sulfate and concentrated in vacuo to give a brown solid. The solid was purified by column chromatography (NH silica gel, eluted with MeOH in EtOAc) to give 50.9 mg of yellow solid. The solid was purified by preparative HPLC (C18, eluted with H2O in acetonitrile containing 0.1% TFA). The desired fraction was neutralized with sat. NaHCO3 aq. and extracted with EtOAc. The organic layer was separated, dried over anhydrous magnesium sulfate and concentrated in vacuo to give the title compound (26.8 mg) as a white solid.
