Triphenylphosphine → tert-Butyl 4-(((6-methoxy-4-oxo-3-((pivaloyloxy)methyl)-3,4-dihydroquinazolin-7-yl)oxy)methyl)piperidine-1-carboxylate

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Reaction Steps

Triphenylphosphine (1.7 g, 6.5 mmol) was added under nitrogen to a suspension of 7-hydroxy-6-methoxy-3-((pivaloyloxy)methyl)-3,4-dihydroquinazolin-4-one (1.53 g, 5 mmol) in methylene chloride (20 ml), followed by the addition of 1-(tert-butoxycarbonyl)-4-(hydroxymethyl)piperidine (1.29 g, 6 mmol), (prepared as described for the starting material in Example 1), and by a solution of diethyl azodicarboxylate (1.13 g, 6.5 mmol) in methylene chloride (5 ml). After stirring for 30 minutes at ambient temperature, the reaction mixture was poured onto a column of silica and was eluted with ethyl acetate/petroleum ether (1/1 followed by 6/5, 6/4 and 7/3). Evaporation of the fractions containing the expected product led to an oil that crystallised following trituration with pentane. The solid was collected by filtration and dried under vacuum to give 7-(1-(tert-butoxycarbonyl)piperidin-4-ylmethoxy)-6-methoxy-3-((pivaloyloxy)methyl)-3,4-dihydroquinazolin-4-one (232 g, 92%).

Provenance & Evidence