CH667088A5 - METHOD FOR PRODUCING N-ALKYL- OR N-ARYLSULPHONYLOXYNAPHTHALIMIDES. - Google Patents

Description

DESCRIPTION The invention relates to a process for the preparation of N-alkyl- or N-arylsulfonyloxynaphthalimides starting from naphthalic anhydride.

N-alkyl- or N-arylsulfonyloxynaphthalimides are important dye intermediates which, after conversion into the corresponding naphtholactams (see UL Plakidin et al. J. Org. Formerly USSR 10 [1974], Part. 2, page 2249) for the production of naphthostyril dyes serve. Such dyes and their preparation are described for example in DE-B-1917456.

A long-known method for the preparation of 1,8-naphtholactam (naphthostyril) starts from naphthalene imide, obtained by heating naphthalic anhydride with aqueous ammonia (Ullmann, 4th ed. Vol. 9 [1975], page 153), that is converted into the naphthostyril by Hofmann degradation (F. Ullmann et al. Chem. Ber. 43, 439

[1910]). The disadvantage of this method is that the desired product is obtained in a relatively low yield.

Also known is a process for the preparation of N-alkyl- or N-arylsulfonyloxynaphthalimides, which likewise starts from naphthalic anhydride. Then naphthalic anhydride is first reacted with hydroxylamine to give the naphthalic hydroximide, the N-hydroxy group of which is then reacted with a sulfochloride, e.g. Benzenesulfonyl chloride, aeylated (DE-A-2417789). The reaction of the naphthoic acid anhydride with hydroxylamine is carried out in a protic solvent, e.g. Water or propionic acid, carried out while in the subsequent acylation in an organic solvent, such as. As methanol or pyridine works. This process is relatively complex: 15 The reaction of the acid anhydride with the hydroxylamine and the subsequent acylation are carried out in various solvents, with isolation of the naphthalic acid hydroximide formed as an intermediate.

Today, efforts are increasingly being made to largely simplify the intermediate product syntheses carried out on a large industrial scale in order to achieve the most efficient process management possible, saving on work steps. In search of a simple process for the preparation of N-alkyl- or N-arylsul-25 fonyloxynaphthalimiden it was found that the naphthalic anhydride in water as a reaction medium successively with hydroxylamine or a hydroxylammonium salt and a sulfochloride without isolating the naphthalic acid hydroximide in a so-called one-pot reaction can be implemented directly to the desired end product. If one takes into account the fact that work is carried out in suspension, the starting material and the product are practically insoluble in water, the reaction proceeds surprisingly uniformly with a good yield and without the use of water as the reaction medium leading to significant hydrolysis of the sulfochloride . Another advantage is that no solvents have to be regenerated by working in water.

The present invention thus relates to a process for the preparation of N-alkyl- or N-arylsulfonyloxy-40 naphthalimides of the formula

O-R

SA /

• •

i i • •

R'— f M 4 — R ''

®v • "•

V

55 wherein R is an alkyl or arylsulfonyl radical and R 'and R "independently of one another are hydrogen, alkyl, alkoxy, halogen, N, N-dialkylamino or nitro, and this is based on the corresponding naphthalic anhydrides, characterized in that using 60 Water as reaction medium converts a naphthalic anhydride into the naphthalic hydroximide using hydroxylamine or a hydroxylammonium salt and, without intermediate isolation, converts it with an alkyl or arylsulfochloride to N-alkyl- or N-arylsulfonyloxynaphthalimide. 65 The reaction proceeds according to the following equation Example of the reaction of naphthalic anhydride with hydroxylamine sulfate and benzenesulfochloride to N-phenylsulfonyloxynaphthalimi d

667 088

v ° \ / • •

I I

/ V \

I II I

(H3N0H) 2S04

OH

SA /

i î

/ V \

i H i o-so, 1

2 \ /

W

Çenzolsulfo- '] I chloride S \ / h - î H î

\ '\ S

Naphthalic acid hydroximide

In addition to naphthalic anhydride, substituted naphthalic anhydrides are also suitable. The abovementioned radicals R 'and R "are primarily hydrogen, but also, for example, also alkyl, in particular lower alkyl having 1 to 4 carbon atoms, such as methyl, ethyl, propyl, butyl or isopropyl or sec-butyl furthermore for alkoxy, in particular lower alkoxy with 1 to 4 carbon atoms, such as methoxy, ethoxy, propoxy, butoxy or also iso-propoxy or tert-butoxy; halogen, such as fluorine, chlorine or bromine or else also come into question Nitro or N, N-dialkylamino group, such as the N, N-dimethylamino group.

The naphthalic anhydride or corresponding derivatives are first reacted with hydroxylamine, advantageously as an aqueous solution, or with a hydroxylammonium salt. As a hydroxylammonium salt such. B. Consider hydroxylamine chloride, sulfate or nitrate; hydroxylamine sulfate is preferably used.

The intermediate naphthalic acid hydroximide is acylated with an alkyl or aryl sulfochloride of the formula R-S02C1. The radical R represents alkyl, in particular lower alkyl having 1 to 4 carbon atoms, such as e.g. Methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl. Furthermore, alkyl should also be understood to mean an alkyl radical substituted by a phenyl radical, such as e.g. Benzyl or phenethyl. In addition, R stands for aryl, in particular for the phenyl radical, which may optionally be substituted, for. B. by methyl, ethyl, chlorine, bromine or the nitro group. Such sulfochlorides are, for example, 2-methylbenzenesulfochloride, 3-methylbenzenesulfochloride, 4-methylbenzenesulfochloride, 2,3-dimethylbenzenesulfochloride, 3,4-dimethylbenzenesulfochloride, 2,6-dimethylbenzenesulfochloride, 3,5-dimethylbenzenesulfochloride, 2-dimethylbenzenesulfochloride -Ethylbenzenesulfochloride, 3-ethylbenzenesulfochloride, 4-ethylbenzenesulfochloride, 2,3-diethyl-benzenesulfochloride, 3,4-diethylbenzenesulfochloride, 2,6-diethylbenzenesulfochloride, 3,5-diethylbenzenesulfochloride, 2-nitrobenzenesulfochloride, . The preferred acylating agent in the present process is benzenesulfonyl chloride.

The reaction of the optionally substituted naphthalenic anhydride with hydroxylamine or the hydroxylammonium salt is advantageously carried out at a temperature from 10 ° C. to the boiling point of the reaction mixture, in particular at a temperature from 60 to 100 ° C. and a pH near the Neutral point, especially at a pH of 6.5 to 7.5.

The acylation of the naphthalic acid hydroximide is expediently carried out at a temperature of 10 to 50 ° C. and a pH of 8 to 13.5.

To adjust the required pH, both in the reaction with hydroxylamine or the hydroxylammonium salt and in the subsequent acylation, an alkali metal or alkaline earth metal hydroxide or carbonate in the form of an aqueous solution or a slurry or a tertiary amine is usually used, such as B. triethylamine or piperidine. The pH is preferably adjusted using an aqueous sodium hydroxide solution.

Depending on the temperature and size of the batch, the reaction time is about 3 to 10 hours. Working up, and this is another advantage of the process described here, is extremely simple since the product is practically insoluble in the reaction medium and can easily be isolated by filtration, centrifugation or decanting. The product is then advantageously washed with water and dried. The N-alkyl or N-arylsulfonyloxynaphthalimides obtained in this way can be further processed directly to give the corresponding naphtholactams. A prior cleaning is generally not necessary.

The method according to the invention is carried out, for example, as follows:

Naphtalic anhydride is suspended in water,

wherein 1 mole of anhydride is conveniently suspended in about 1 liter of water, and the suspension is mixed with 3o an approximately equimolar amount of hydroxylammonium salt, e.g. B. hydroxylamine sulfate. It has proven expedient to use the hydroxylammonium salt in a slight excess, advantageously with a 10% excess, based on the equimolar amount. The reaction mixture is then heated to about 900 ° C. and a pH of about 6.5 to 7.5 is established by adding sodium hydroxide solution.

After a reaction time of about 1 to 3 hours, the reaction mixture is allowed to cool to room temperature and the pH is increased to 40> 10, advantageously to about 13, by adding sodium hydroxide solution. Then the sulfochloride is added, e.g. Benzenesulfochloride, also advantageous here with about 10% excess, based on the equimolar amount. As the acylation progresses, the pH of the reaction mixture drops below pH 10 to about pH 9. After 45 about 2 to 5 hours, the reaction is complete and the product is filtered off. The O-acylnaphthalic acid hydroximide is then washed with water and then dried. The yields achieved by this process are generally over 90%.

so The following example serves to illustrate the invention; Parts mean parts by weight and percentages percent by weight.

Example: 99.1 parts of naphthalic anhydride are suspended in 500 parts of water and 45.1 parts of hydroxyl-55 amine sulfate are added. The suspension is heated to 90 ° C., about 60 parts of a 50% sodium hydroxide solution are added dropwise, and the pH is thus adjusted to 6.5 to 7.5. After stirring for one hour at 90 ° C, the reaction mixture is cooled to 25 ° C and about 44 parts of 50% sodium hydroxide solution are added dropwise, which gives a pH of about 13.5. 98 parts of benzene sulfochloride are then added dropwise at room temperature within 1 hour. During the acylation, the pH falls and after a further hour is about 9. The reaction has almost completely ended at this point. The product is filtered off, washed with water and dried. 163 parts of N-phenylsulfonyloxynaphthalimide are obtained, which corresponds to a yield of 92%. The product has a melting point of 206 ° C.

G

Claims (6)

667 088 2. The method according to claim 1, characterized in that one carries out the reaction of the optionally substituted naphthalic anhydride with hydroxylamine or a hydroxylammonium salt at a temperature of 10 ° C to the boiling point of the reaction mixture and a pH near the neutral point. 2nd PATENT CLAIMS 1. Process for the preparation of N-alkyl- or N-aryl-sulfonyloxynaphthalimides of the formula 0-R W I I , / V \ R1 — b II H — R "• VV wherein R is an alkyl or arylsulfonyl radical and R 'and R "independently of one another are hydrogen, alkyl, alkoxy, halogen, N, N-dialkylamino or nitro, starting from the corresponding naphthalic anhydrides, characterized in that using water as the reaction medium a naphthalic anhydride is converted into the naphthalic hydroximide by means of hydroxylamine or a hydroxylammonium salt and this is reacted without isolation with an alkyl or arylsulfochloride to give the N-alkyl- or N-arylsulfonyloxynaphthalimide. 3. The method according to claim 2, characterized in that one works at a temperature of 60 to 100 ° C and a pH of 6.5 to 7.5. 4. The method according to claim 1, characterized in that one carries out the reaction of the naphthalic hydroximide with the alkyl or aryl sulfochloride at a temperature of 10 to 50 ° C and a pH of 8 to 13.5. 5. Process according to claims 1 to 4, characterized in that one starts from naphthalic anhydride and this is reacted with hydroxylamine sulfate and then with benzenesulfonyl chloride to give N-phenylsulfonyloxynaphthalimide. 6. The N-alkyl or N-arylsulfonyloxynaphthalimides obtained by the process according to claim 1.