Pyrazolo-quinazolone compounds

摘要

The invention comprises the heterocyclic compounds of formula: wherein R1 is a hydrogen atom or an alkyl or aryl radical which may be substituted or a carboxylic acid ester group, R2 is a hydrogen atom or an alkyl radical, or R1 and R2 can together form a carbocyclic ring, R3 is a hydrogen atom or an alkyl radical or a phenyl radical which may be substituted and Ar is an orthocondensed, mono- or poly-nuclear, substituted or unsubstituted aromatic ring system including a benzene nucleus substituted by a pyrazoloquinazolonyl ring system of formula: wherein R1, R2 and R3 are as defined above The compounds are prepared by reacting an appropriate aromatic o-amino-carboxylic acid hydrazide the amino group of which contains at least one hydrogen atom with an appropriate beta-keto-carboxylic acid ester. In examples the preparation of the following compounds is described: 31-methyl- or -phenyl- or -(m-nitrophenyl)-pyrazolo-(11, 51, 3, 2)-quinazolone, 31-methyl-pyrazolo-(11, 51, 3, 2)-5-chloro- or -6-acetylamino- or -7- amino or -nitro-quinazolone, 31-methyl-pyrazolo-(11, 51, 3, 2)-quinazolone-6-sulphonamide or -sulphonic acid, 31-methyl-pyrazolo-(11, 51, 3, 2)-6, 7-benzoquinazolone, pyrazolo-(11, 51, 3, 2)-quinazolone -31- acetic acid methyl ester, 1, 31-dimethyl-pyrazolo-(11, 51, 3, 2)-quinazolone, 31, 41-dimethyl- or -tetramethylene-pyrazolo-(11, 51, 3, 2)-quinazolone, pyrazolo-(11, 51, 3, 2)-quinazolone -31-carboxylic acid ethyl ester, 31-methyl-pyrazolo-(11, 51, 3, 2)-quinazolone -7- or -8- carboxylic acid, 1-phenyl-31-methyl-pyrazolo-(11, 51, 3, 2)-quinazolone, 1-methyl-31, 41-tetramethylene-pyrazolo-(11, 51, 3, 2)-quinazolone and bis-[31-methyl-pyrazolo-(11, 51, 3, 2)-quinazolonyl-(6)]. 6-chloro -2- aminobenzoic acid hydrazide is prepared by treating 2-amino -6- chlorobenzoic acid with phosgene to yield the corresponding chloro-isatoic acid anhydride and reacting this with excess hydrazine hydrate; 2-amino -5-acetylamino-benzoic acid hydrazide, 2-amino-1, 3-benzene-dicarboxylic acid hydrazide-(1) and 2-amino -5- sulpho-benzoic acid hydrazide are prepared in the same way. 2, 4-diamino-benzoic acid hydrazide is prepared by catalytically hydrogenating 4-nitro -2- aminobenzoic acid ethyl ester and reacting the resultant 2, 4-diaminobenzoic acid ester with hydrazine hydrate in ethylene glycol. 4-nitro -2- aminobenzoic acid hydrazide is prepared by treating the corresponding ethyl ester with hydrazinehydrate in ethylene glycol. Benzidine -3, 31- dicarboxylic acid dihydrazide is prepared by heating the corresponding dimethyl ester with hydrazine hydrate.