Triphenylphosphine → 7-(3-Bromopropoxy)-6-methoxy-3-((pivaloyloxy)methyl)-3,4-dihydroquinazolin-4-one

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Reaction Steps

To a suspension of 7-hydroxy-6-methoxy-3-((pivaloyloxy)methyl)-3,4-dihydroquinazolin-4-one (29 g, 94.7 mmol), (prepared as described for the starting material in Example 12), in methylene chloride (280 ml) coiled at 5° C. was added triphenylphosphine (37.1 g, 141.6 mmol) followed by 3-bromo-1-propanol (12.8 ml, 141.6 mmol) and diethyl azodicarboxylate (2.4 ml, 141.6 mmol) dropwise. After stirring for 2 hours at ambient temperature, the volatiles were removed under vacuum and the residue was purified by column chromatography eluting with methylene chloride/methanol (98/2). The fractions containing the expected product were combined and evaporated and the solid was triturated with ether, filtered, washed with ether and dried under vacuum to give 7-(3-bromopropoxy)-6-methoxy-3-((pivaloyloxy)methyl)-3,4-dihydroquinazolin-4-one (37.22 g, 92%).

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