Certain 2-methyl-3-phenyl-(4)3h-quinazolones

Novel compounds of the general formula in which Z represents a benzene ring which may be substituted, if desired, by at least one alkyl or alkoxy group containing 1 to 3 carbon atoms, R1 and R2 represent hydrogen atoms or alkyl groups containing 1 to 3 carbon atoms, and R3, R4, R5 and R6, which may be the same or different, represent hydrogen or halogen atoms or alkyl or alkoxy groups containing 1 to 3 carbon atoms, at least one of R3, R4, R5 and R6 being other than a hydrogen atom, and acid addition salts thereof, are prepared (a) where R1 and R2 are both hydrogen, by reduction of the corresponding nitro or nitroso compound; (b) by condensing a substituted acetylanthranilic acid with a phenylenediamine in the presence of a dehydrating agent; (c) where R1 and R2 are both hydrogen, by removal of a protecting group from the corresponding amine protected compound, e.g. hydrolysis of an acyl amino group; or (d) by heating a substituted acetylanthranil with a phenylenediamine. 2 - Methyl - 3 - (nitrophenyl) - 3H - 4 - quinazolones are prepared by condensing a substituted acetylanthranilic acid or a substituted acetylanthranil with a compound of the formula H2N-Z-NO2, if necessary in the presence of a dehydrating agent. Acylaminoquinazolones of the above general formula wherein one of R1 or R2 is acyl and the other hydrogen are prepared by condensing a substituted acetylanthranilic acid or a substituted acetylanthranil with a compound of the formula H2N-Z-A, wherein A is an acylamino group. 3,5 - Dimethyl - acetylanthranilic acid is prepared in conventional manner by acetylation of the corresponding dimethyl anthranilic acid. 2 - Methyl - 3 - (2 - methyl - 4 - aminophenyl)-8-chloro-3H - 4 - quinazolone is prepared by permanganate oxidation of 3 - chloro - 2 - acetamido-toluene. 2 - Methyl - 3 - (2 - methyl - 4 - aminophenyl) 5,6 - dichloro - 3H - 4 - quinazolone is prepared by chlorination of 6-chloro-acetylanthranilic acid in glacial acetic acid. Pharmaceutical compositions, having sedative and anti-convulsant activity, for oral, rectal or parenteral administration, preferably in unit dosage form in the form of tablets, coated tablets, capsules, ampoules or suppositories, comprise a compound of the first general formula above and at least one pharmaceutical carrier or excipient.