3,4-dihydro-2H-pyran → 5-Iodo-2-(tetrahydro-2H-pyran-2-yl)pyridazin-3(2H)-one

Participants

Reaction Steps

A solution of 5-iodo-2H-pyridazin-3-one (66 g, 0.30 mol) in tetrahydrofuran (500 mL) was treated with pyridinium para-toluene sulfonate (14.3 g, 0.057 mol) and 3,4-dihydro-2H-pyran (52 mL). The reaction mixture was stirred at reflux for 5 h. At this time, the reaction was treated with another aliquot of 3,4-dihydro-2H-pyran (32.5 mL). The solution was stirred at reflux overnight. At this time, the solution was concentrated in vacuo. Chromatography (ethyl acetate/petroleum ether=1/2) afforded 5-iodo-2-(tetrahydro-pyran-2-yl)-2H-pyridazin-3-one (89 g, 98%).

Provenance & Evidence