Hydrochloric Acid → 5-hydroxy-7-methoxy-3-(4-methoxyphenyl)-4(3H)-quinazolinone

Participants

Reaction Conditions

Reaction Steps

A suspension of 5,7-dimethoxy-3-(4-methoxyphenyl)-4(3H)-quinazolinone (2.40 g, 7.68 mmol), as prepared in Example 18 or 19 and anhydrous lithium chloride (6.51 g, 153.6 mmol) in anhydrous dimethylacetamide (51.2 mL) was warmed to 135° C. After 3 to 5 min the trimethoxy compound goes into solution, then after approximately 10 min a voluminous precipitate formed. The precipitate redissolved after 20 min and the resulting solution was stirred at 135° C. for an additional 2.5 h. Upon cooling to room temperature, the reaction was poured into water (100 mL) and acidified with 1.0N HCl which gave a white precipitate. The mixture was extracted with dichloromethane (3×). The combined organic layers were washed with brine, dried over MgSO4, filtered, and concentrated in vacuo to remove the methylene chloride, leaving a white precipitate in dimethylacetamide. Filtration provided 1.10 g (48% yield) of 5-hydroxy-7-methoxy-3-(4-methoxyphenyl)-4(3H)-quinazolinone, as a white solid.

Provenance & Evidence