GB965160A - - Google Patents

Abstract

965,160. Pyrazole-naphthol derivatives. FERRANIA S.p.A. Nov. 27, 1962, No. 44790/62. Heading C2C. [Also in Division G2] 2-(5-methyl-3-pyrazolyl)- 1-naphthol is prepared by refluxing #-acetylaceto-α-naphthol with hydrazine hydrate in ethyl alcohol. Alternatively, it may be obtained by reacting 2-methyl-benzo-. chromone with hydrazine hydrate. By using phenyl hydrazine or the appropriately substituted phenyl hydrazine in the first reaction, 2- (2 phenyl-5-methyl-3-pyrazolyl)-1-naphthols are obtained in which the phenyl group may have p-cyano, p-nitro, p-carboxy, 2;4;6-trichloro or 3 ;5-dicarbomethoxy substituents. By using 2- benzothiazolyl hydrazine, 2-[2-(benzothiazolyl-2)- 5-methyl-3-pyrazolyl]-1-naphthol is obtained. The above compound having a p-nitrophenyl substituent on the pyrazolyl ring is reduced with tin and hydrochloric acid to give the corresponding amine and this is reacted with 3-chlorosulphobenzoyl-(2<SP>1</SP>-N-ethyl-N-cetylamino-5<SP>1</SP>-sulpho-anilide) to give a compound of the formula: The 2-(2-p-carboxyphenyl-5-methyl-3-pyrazolyl) 1-naphthol obtained above is reacted with thionyl chloride to give the acid chloride, and this in turn is reacted with 3-carboxy-5-stearoylamino-aniline to give a compound of the formula: The compound having the formula: is obtained by reacting 2-(5-methyl-3-pyrazolyl)- I-naphthol with p-chlorosulpho-phenyl isocyanate to substitute a p-chlorosulphophenyl-carbamidegroup in the 2-position of the pyrazole ring, and this is then reacted with 3-amino-5-stearylaminobenzoic acid. Specification 935,698 is referred to.