Novel synthesis of bis pyrazolone oxonol dyes

Details Novel synthesis of bis pyrazolone oxonol dyes Novel synthesis of bis pyrazolone oxonol dyes

1978-03-03

1980-02-05

Randolph, John D.

Chemistry of carbon compounds

Miscellaneous organic carbon compounds

C-metal

2603977R, 430522, C07D 2342, C09B 2302

Patent

active

041872258

ABSTRACT:
In one embodiment, this application is directed to an improved method of synthesizing certain bis-pyrazolone oxonol compounds useful as antihalation dyes in photography which method comprises synthesizing a pyrazolone ethyl ester by reacting a p-N-alkylsulfonamidophenylhydrazine or its hydrochloride and sodium diethyl oxalacetate, hydrolyzing the pyrazolone ethyl ester thus formed to give the corresponding pyrazolonecarboxylic acid, esterifying the pyrazolonecarboxylic acid with a glycol to give the corresponding pyrazolone hydroxyalkyl ester and condensing said pyrazolone hydroxyalkyl ester with an aldehyde dianil hydrochloride to yield the dye product.
In another embodiment, the p-N-alkylsulfonamidophenylhydrazine is prepared by reacting p-fluorobenzenesulfonyl chloride and a primary alkylamine to yield the corresponding 1-fluoro-4-N-p-alkylsulfonamidobenzene and then reacting said alkylsulfonamidobenzene with hydrazine hydrate to yield the corresponding p-N-alkylsulfonamidophenylhydrazine which may be converted to its hydrochloride salt by reaction with a solution of hydrochloric acid.

REFERENCES:
patent: 3839325 (1974-10-01), Hoffstadt
patent: 3933798 (1976-01-01), Curtis et al.
Bader et al., J. Org. Chem. vol. 31, pp. 2319 to 2321 (1966).

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