Patent GB-436516-A (GB)
Title: Manufacture of sulphonic acid and carboxylic acid derivatives of 1:3-diaryl-5-pyrazolones
IPC: E05B35/00
Filed: 1934-03-05
Abstract: 1 : 3-Diaryl-5-pyrazolones, substituted with at least one sulphonic or carboxylic group or both in at least one of the aryl radicles, are prepared by subjecting to ring closure the hydrazones obtained from correspondingly substituted arylhydrazines and aroylacetic esters. The production of the hydrazone and the ring closure are effected in an aqueous medium, and may be conducted without isolation of the hydrazone; the production of the hydrazone is preferably effected in an acid medium, and the ring closure in an alkaline medium.  In the examples, (1) benzoylacetic ester is condensed (a) with 2-sulphophenylhydrazine, yielding 1 - (2<1> - sulphophenyl) - 3-phenyl-5-pyrazolone, and (b) with 3-sulphophenylhydrazine, 4 - sulphophenylhydrazine, 2-chloro-4-sulphophenylhydrazine, 2-chloro-5-sulphophenylhydrazine, 3 : 4-dichloro-6-sulphophenylhydrazine, 2-hydroxy-3-carboxy-5-sulphophenylhydrazine, 2-methyl-4-sulphophenylhydrazine 4 - carboxyphenylhydrazine, 4<1>-hydroxy-3<1>-carboxy-4-sulpho-1 : 1<1>-diphenylsulphone - 2 - hydrazine, 3 - methyl - 4 - chloro - 6-sulphophenylhydrazine, 2 : 5-dichloro-4-sulphophenylhydrazine, 1-sulpho-2-naphthylhydrazine, 4-nitro-2-sulphophenylhydrazine, 2-nitro-4-sulphophenylhydrazine, 2 : 5-disulphophenylhydrazine, and 2-methyl-4 : 5-disulphophenylhydrazine, yielding the corresponding 1-aryl-3-phenyl-5-pyrazolones; (2) p-chlorobenzoylacetic ester is condensed with 3-sulphophenylhydrazine, yielding 1-(3<1>-sulphophenyl)-3-(4<1>-chlorophenyl)-5-pyrazolone; (3) m-nitrobenzoylacetic ester and 2-sulphophenylhydrazine yield 1-(2<1>-sulphophenyl)-3-(3<1>-nitrophenyl)-5-pyrazolone; (4) 4-methylbenzoylacetic ester and 2-chloro-5-sulphophenylhydrazine yield 1-(2<1>-chloro-5<1>-sulphophenyl) - 3 - (4<1> - methylphenyl) - 5 - pyrazolone; (5) 4-methoxybenzoylacetic ester and 2-hydroxy-3-carboxy-5-sulphophenylhydrazine yield 1 - (2<1> - hydroxy - 3<1> - carboxy - 5<1> - sulphophenyl) - 3 - (4<1> - methoxyphenyl) - 5 - pyrazolone; (6) 2 : 4-dichlorobenzoylacetic ester and 4-sulphophenylhydrazine yield 1-(4<1>-sulphophenyl)-3 - (2<1> : 4<1> - dichlorophenyl) - 5 - pyrazolone; (7) a -naphthoylacetic ester and 1-sulpho-2-naphthylhydrazine yield 1-(2<1>-naphthyl-1<1>-sulpho)-3 - (1<1> - naphthyl) - 5 - pyrazolone; (8) b -naphthoylacetic ester and 3 : 4-dichloro-6-sulphophenylhydrazine yield 1-(3<1> : 4<1>-dichloro-6<1>-sul phophenyl) - 3 - (2<1> - naphthyl) - 5 - pyrazolone; (9) 4-phenylbenzoylacetic ester and 3-sulphophenylhydrazine yield 1-(3<1>-sulphophenyl)-3-(4<1> - diphenyl) - 5 - pyrazolone; (10) 4-carboxybenzoylacetic ester is condensed (a) with 2 - chloro - 5 - sulphophenylhydrazine, yielding 1-(2<1>-chloro-- 5<1>-sulphophenyl) - 3 - (4<1> - carboxyphenyl)-5-pyrazolone, and (b) with 4-sulphophenylhydrazine, 2-sulphophenylhydrazine, phenylhydrazine, m-carboxyphenylhydrazine, 2-hydroxy-3-carboxy-5-sulphophenylhydrazine, 1 - sulpho - 2 - naphthylhydrazine, and 4-nitrophenylhydrazine, yielding the corresponding 1 - aryl - 3 - (4<1>-carboxyphenyl) - 5 - pyrazolones; (11) m-chlorobenzoylacetic ester and 4 - nitro-2-sulphophenylhydrazine yield 1-(4<1>-nitro-2<1>-sulphophenyl) - 3 - (3<1> - chlorophenyl) - 5 - pyrazolone; (12) 4-nitrobenzoylacetic ester and 2-nitro-4-sulphophenylhydrazine yield 1-(2<1>-nitro - 4<1> - sulphophenyl) - 3 - (4<1> - nitrophenyl)-5-pyrazolone.  Hydrazines.--The arylhydrazines specified above are obtainable by treating the diazo compounds of the corresponding bases with sodium sulphite, reducing the diazosulphonates so obtained with sulphurous acid or zinc dust, and saponifying the resulting hydrazinesulphonates with an inorganic acid; alternatively, the diazo compounds may be reduced directly to the hydrazines with stannous chloride.  Aroylacetic esters.--p - Carboxybenzoylacetic acid ethyl ester is obtainable by treating a terephthalic acid monoalkyl ester with thionyl chloride to yield the mono-acid chloride, condensing this with acetoacetic ester to yield the corresponding aroylacetoacetic ester, splitting off the acetyl group, for instance with ammonia, and saponifying the ester group attached to the benzene ring with alcoholic caustic alkali.  The other aroylacetic esters specified above are similarly obtainable from the corresponding aroyl chloride and acetoacetic ester.  The Specification as open to inspection under Sect. 91 describes the preparation of 1-(4<1>-diphenyl - 4<11> - sulpho) - 3 - phenyl - 5 - pyrazolone from 4<1> - sulpho - 4 - diphenylhydrazine and benzoylacetic acid ethyl ester.  This subject-matter does not appear in the Specification as accepted.