Water → 6-Acetoxy-7-methoxy-3H-quinazolin-4-one

Participants

Reaction Conditions

Reaction Steps

A mixture of 6,7-dimethoxy-3,4-dihydro-quinazolin-4-one (20.0 g, 97 mmol) and racemic methionine (21.7 g, 146 mmol) in methanesulphonic acid (150 ml) were heated at 100° C. for 5.5 hours and then allowed to cool to ambient temperature over 18 hours. The reaction was poured into cold water (750 ml), the pH of the aqueous solution was adjusted to pH 6 (by addition of 2.0N aqueous sodium hydroxide solution) and the solid which formed was collected by suction filtration. The solid was dried in vacuo and then dissolved in a mixture of pyridine (20 ml) and acetic anhydride (150 ml). The solution was heated at 100° C. for 1 hour, cooled and poured into cold water (1050 ml). Collection of the resultant solid by suction filtration, followed by drying in vacuo, yielded 6-acetoxy-7-methoxy-3,4-dihydro-quinazolin-4-one (13.9 g, 57% yield) as a pale-brown solid:

Provenance & Evidence