CS213011B1 - Method of making the benzo/c/fluorene derivatives - Google Patents

Abstract

A new way of producing 5-hydroxy-7-oxo-7H- -benzo / c / fluorene and its 3,9-dimethylanalog% consisting of the reaction of 4-phenyl-2,3-dicyano-l- -naphthol, respectively. 7-Methyl-4- (4-methylphenyl) -2,3-dicyano-1-naphthol, with dilute acid sulfuric acid in acetic acid at Elevated temperature, ranging from 100 ° C to boiling point of the reaction mixture.

Description

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Process for producing benzo (c) fluorene derivatives

A novel process for the preparation of 5-hydroxy-7-oxo-7H-benzo [c] fluorene and its 3,9-dimethylanalogene by reacting 4-phenyl-2,3-dicyano-1-naphthol and the like. 7-methyl-4- (4-methylphenyl) -2,3-dicyano-1-naphthol, with dilute sulfuric acid in acetic acid at elevated temperature, ranging from 100 ° C to the boiling point of the reaction mixture.

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The present invention relates to a process for the preparation of bonze (c) fluorone derivatives of the general formula (I)

The compounds of formula (I), as defined above for R, are known and can be prepared, for example, according to the author's certificates No. 200 094 and a.o. The process according to the prior art consists of reacting a compound of the formula II

in which R has the same meaning as above, with dilute sulfuric acid in an eoteva acid medium. A number of reactions take place in this environment, including demethylation, hydrelysis and cyclization of the interaedially formed carboxyl derivative, resulting in a mixture of products in which the compounds of formula 1, e, as defined above, are dependent on reaction conditions, i.e. temperature, reaction time and the ratio of the campenent in the reaction medium (sulfuric-veda-acetic acid). Depending on these conditions, the corresponding 4-phenyl-1-methexynaphthalene-2,3- (1-bicyclohexylic anhydride) and the like are also formed in the reaction mixture in addition to the desired substances. 7-methyl-4- (4-methylphenyl) -1-methexynaphthalene-2,3-dicarboxylic acid. Simultaneously, the presence of sulfuric acid leads to sulphonation of substances, formation of colored products, depending on temperature and reaction time. It is necessary to remove these substances from the final product by crystallization or by column chromatography, which increases the laboriousness of the production process and reduces the yields.

The present inventors have now not found that compounds of formula I, having the above-mentioned meaning of R, can advantageously be prepared from compounds of formula III κ

(111), wherein R is as defined above, by treatment with sulfuric acid at a concentration of 30 to 80% in an acetic acid medium at temperatures from 100 ° C to the boiling point of the reaction mixture.

After completion of the reaction, the reaction mixtures are poured into water and the precipitated organic phase is filtered off with suction, washed with water and purified by crystallization.

In contrast to the previous process, the above-mentioned new process uses a deaethylated dicyanoderivative (substances of general formula 111, as defined above for R) as starting material, thereby ₍

213 011, the course of the hydrelysis and cyclization reaction, compared to the methylated substance, is facilitated. Due to the high resistance to intermediate demethylation, the methyllevel of formula (II) as defined above requires, on the one hand, larger volumes of reaction media and, on the other hand, larger volumes of sulfuric acid, leading to increased formation of color by-products. substances.

The compounds of the general formula (III), as defined above for the meaning of R, are known substances and are available, for example, from U.S. Pat. Certificate of Authentication 212 636.

The following is a non-limiting example of the method of preparation of the compounds of formula (I) with the meaning of R given above. 5-Hydroxy-7-exo-7H-benzo [f] fluorene

To a suspension of 10.0 g (0.07 mol) of 4-phenyl-2,3-dicyano-1-naphthol in 200 ml of acetic acid and 100 ml of water was added dropwise 140 ml of sulfuric acid dropwise with stirring and the reaction mixture was refluxed for 6 hours. After cooling and pouring into 5 l of water, the precipitate formed is filtered off with suction, washed with water and the product obtained is taken up in 500 ml of water and briefly charged (about 10 minutes), the crystalline precipitate is filtered off with suction and dried. A material of m.p. 255-257 ° C.

By anrloric procedure, the use of 7-methyl-4- (4-methylphenyl) -2,3-dicyano-1-naphthel as the starting 1a-c, 9-dimethyl-5-hydroxy- 7-oxo-7H-benzo [c] fluorene: limits from 260

Claims (1)

SUBJECT OF THE INVENTION A process for the preparation of the benzo (c) fluorene derivatives of the general formula (I) -R (1) in which R is a hydrogen atom or a methyl group, characterized in that the compounds of formula III (III) in which R is as defined above are reacted with dilute sulfuric acid (30 to 80%), in acetic acid, at temperatures ranging from 100 ° C to the boiling point of the reaction mixture,