Formamidine acetate → Tert-butyl 4-(4-oxo-3,4-dihydrothieno[3,2-d]pyrimidin-7-yl)piperidine-1-carboxylate

Participants

Reaction Steps

tert-Butyl 4-[4-amino-5-(ethoxycarbonyl)thiophen-3-yl]piperidine-1-carboxylate (307 mg, 0.87 mmol) was dissolved in ethanol (8 mL), and then formamidine acetate (542 mg, 5.20 mmol) was added, followed by heating under reflux for 36 hours. The reaction liquid was concentrated under a reduced pressure, and the obtained residue was dissolved in chloroform. The organic layer was washed with saturated brine, dried over anhydrous sodium sulfate and concentrated under a reduced pressure. The obtained residue was purified by using silica gel chromatography (chloroform:methanol=10:1) to give tert-butyl 4-(4-oxo-3,4-dihydrothieno[3,2-d]pyrimidin-7-yl)piperidine-1-carboxylate (62.5 mg, 21.5%) as a pale yellow amorphous.

Provenance & Evidence