Acetic Anhydride → 2-Methyl-4(3H)-quinazolinone
Reaction equation
Cl.[C:2]([NH2:11])(=[O:10])[C:3]1[C:4](=[CH:6][CH:7]=[CH:8][CH:9]=1)[NH2:5].[C:12](OC(=O)C)(=O)[CH3:13]>>[CH3:12][C:13]1[NH:11][C:2](=[O:10])[C:3]2[C:4](=[CH:6][CH:7]=[CH:8][CH:9]=2)[N:5]=1Participants
Procedure
Anthranilamide hydrochloride was prepared by adding 20 ml of concentrated hydrochloric acid (37% by weight) to a solution of 27.3 g of anthranilamide in 200 ml of methanol. This mixture was cooled in an ice bath to precipitate the hydrochloride which was then collected and dried to obtain a product melting at 234°C with decomposition. A 17.4 g (0.1 mole) portion of the hydrochloride obtained above was refluxed for 3 hours with 100 ml acetic anhydride and allowed to stand overnight. The mixture was then cooled in an ice bath and the solids collected by filtration on a Buchner funnel. The filter cake was slurried in 100 ml of water, and warmed to aid solution and then 28% aqueous ammonia was added until the mixture was alkaline. After cooling the 2-methyl-4-(3H)quinazolinone precipitated as a solid, was then collected, washed with a small amount of cold water and dried at 70°C to obtain 6.72 g of the desired product. The 2-methyl-4-(3H)quinazolinone melted at 236°-8°C and was obtained in a 42% yield.
Workup
- temperatureThe mixture was then cooled in an ice bath
- filtrationthe solids collected by filtration on a Buchner funnel
- temperaturewarmed
- addition28% aqueous ammonia was added until the mixture
- temperatureAfter cooling the 2-methyl-4-(3H)quinazolinone
- customprecipitated as a solid
- customwas then collected
- washwashed with a small amount of cold water
- customdried at 70°C
Sources & evidence
- ORD record
- ord-b766ece4d7164b9981899e4478b4834d
- Source dataset
- uspto-grants-1976_08
- Patent number
- US03973021
Reaction notes
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