Triphenylphosphine → 6-Methoxy-3-((pivaloyloxy)methyl)-7-(2-(pyrrolidin-1-yl)ethoxy)-3,4-dihydroquinazolin-4-one

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Reaction Steps

Diethyl azodicarboxylate (566 mg, 3.25 mmol) was added dropwise to a solution of 7-hydroxy-6-methoxy-3-((pivaloyloxy)methyl)-3,4-dihydroquinazolin-4-one (765 mg, 2.5 mmol), (prepared as described for the starting material in Example 22), 1-(2-hydroxyethyl)pyrrolidine (374 mg, 3.25 mmol) and triphenylphosphine (851 mg, 3.25 mmol) in methylene chloride (15 ml). The mixture was stirred for 1 hour at ambient temperature and further triphenylphosphine (861 mg, 3.25 mmol) followed by diethyl azodicarboxylate (566 mg, 3.25 mmol) was added. The mixture was stirred for 1 hour at ambient temperature and the solvent was removed by evaporation. The residue was dissolved in ethyl acetate/ether and extracted with 2M hydrochloric acid. The aqueous layer was basified by addition of solid sodium hydrogen carbonate and extracted with methylene chloride. The combined extracts were dried (MgSO4), and the solvent removed by evaporation. The resulting oil was purified by column chromatography on neutral aluminium oxide eluting with methylene chloride/methanol (90/10 followed by 80/20) to give 6-methoxy-3-((pivaloyloxy)methyl)-7-(2-(pyrrolidin-1-yl)ethoxy)-3,4-dihydroquinazolin-4-one (550 mg, 55%).

Provenance & Evidence