GB1577554A - Manufacture of naphtholactam - Google Patents

Abstract

Naphtholactam, which has the formula I, is prepared by reacting naphthalic hydroxyimide with an alkali metal alkoxide (alcoholate). The reaction is carried out in the presence of a sulphonyl (sulphonic acid) halide or of a phosphoric ester halide and of an alcohol and a basic compound. The process of the invention gives the naphtholactam in good yield and purity on an industrial scale. <IMAGE>

Description

(54) MANUFACTURE OF NAPHTHOLACTAM (71) We, BASF AKTIENGESELLSCHAFT, a German Joint Stock Company of 6700 Ludwigshafen, Federal Republic of Germany, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following Statement:- The present invention relates to a new process for the manufacture of naphtholactam.

An article by M. M. Daschevskii in Reports from the Higher Teaching Institutes of the U.S.S.R., 1961, No. 2, Chemistry and Chemical Engineering Section, pages 232-237, reviews the processes for the manufacture of naphtholactam by Hofmann degradation of naphthalimides. According to this author's statements, it is ture that the degradation of naphthalimides gives naphtholactam in yields of from 85 to 90 per cent, but it is pointed out that the reaction must be carried out at very high dilution, e.g. with 20 grams of naphthalimide in 1,740 grams of aqueous alkaline solution, and that the rearrangement with hypochlorite is carried out at from 18 to 200C, since otherwise the naphtholactam and hypochlorite undergo side-reactions, and a substantial proportion of the end product resinifies.

The rearrangement of N-phenylsulfonyloxynaphthalimide to naphtholactam in the presence of very large amounts of solvent is disclosed in Zhurnal Organischeskoi Khimii, 6 (1970), No. 7, 1,48-1,485. An excess of sodium hydroxide is used as the alkali and an alcohol/water mixture is used as the solvent.

The process is unsatisfactory, particularly on an industrial scale, because the starting material is difficult to obtain and the process is neither simple and economical to operate nor gives a good space-time yield.

German Laid-open Application DOS 2,417,789 discloses a rearrangement of halogen-substituted naphthalamide-N-oxysulfonic acid esters and of corresponding phosphoric acid esters. Here again, the starting material must first be manufactured in a separate process, requiring reaction times of from 2 to 5.5 hours and an excess of solvent, and must be isolated. The examples show that to give advantageous results the isolated ester starting material must furthermore be washed thoroughly.

According to the present invention, there is provided a process for the manufacture of naphtholactam, of the formula

wherein naphthalic acid hydroxyimide, of the formula

is reacted with an alkali metal alcoholate in the presence of a sulfonic acid halide of the formula

or of a phosphoric acid ester halide of the formula

where the individual radicals R2 are identical or different and R' and the radicals R2 are each an aliphatic or aromatic radical and X is halogen, in the presence of an alcohol and of a basic compound.

If sodium methylate is used, the reaction may be represented by the following equation:

Compared to the conventional processes, the process of the invention can give naphtholactam more simply and more economically, specifically also on an industrial scale, in most cases in better yield, very good purity and better spacetime yield, and furthermore starts from naphthalic acid-hydroxyimide, which is toxicologically safe and readily accessible. Compared to the Hofmann degradation of naphthalimides, hypochlorite is not needed and hence the danger of a further reaction with naphtholactam can be avoided. Accordingly, the process is simpler and above all safer in operation, since chlorine-nitrogen compounds present safety problems. The process can be carried out more simply from the point of view of the number of steps and from a safety point of view, dispenses with the costs, equipment and operations required for the manufacture of a N-oxyester, and thus causes less pollution of the environment. All these advantageous results are surprising since it would have been expected, in carrying out a reaction with the above reactants in the starting mixture, that the naphthalic acid hydroxyimide-Noxyester, which according to the prior art is an essential starting material for the formation of the naphtholactam, would not form, or would at most form in small amounts, and that therefore a rearrangement to naphtholactam would occur to only a slight degree, if at all. It was also to be assumed that the N-oxyester formed would again dissociate in the presence of strong bases such as alkali metal alcoholates. On the other hand, compounds III and IV are powerful acylating agents and it was therefore to be expected that only naphtholactam acylated at the nitrogen, but no unsubstituted naphtholactam, would be formed. It was also surprising that, for example, naphthalic acid hydroxyimide, alkali metal alcoholate and benzenesulfonyl chloride should, in the presence of an alcohol, undergo conversion to the naphtholactam at all, since, as disclosed in Houben-Weyl, volume 9, pages 663-665, benzenesulfonic acid esters are manufactured from benzenesulfonyl chloride and alcohols in the presence of basic catalysts, whilst Organic Syntheses, Coll. Vol. 1 (1937), pages 139-141, discloses that butyl toluenesulfonate is manufactured from toluenesulfonyl chloride, butanol and sodium hydroxide. In turn, the ester formed is a powerful alkylating agent which would have been expected to convert any small amounts of naphtholactam formed into N-alkylnaphtholactam. It was also to be expected that the strong bases would hydrolyze at least a part of compounds III and IV, to form alkali metal halides, alkali metal sulfonates and alkali metal phosphates. An additional consideration is that both the components and the products of the above numerous reactions between the individual components, e.g. the alkali metal salts formed, lower or selectively influence the solubility of the total mixture, so that it was to be expected that impure solids would precipitate, containing coprecipitated constituents of the mixture. In this context it was not to be expected, furthermore, that in the process according to the invention it would be preferred to use less solvent than in the conventional processes. It was therefore surprising that the process according to the invention, instead of giving difficult-to-separate mixtures of numerous heterogeneous components, e.g. hydrolysis products, salts and decomposition products which can barely be separated, should give naphtholactam at all without prior isolation and purification of the N-hydroxyester, and even more surprising that it should give naphtholactam in good yield, and high purity, without laborious isolation operations, particularly on an industrial scale.

As a rule, alkali metal alcoholates of the formula Z-OR3 V are used, whilst the alcohols which serve as the reaction medium have the formula R40H VI where R3 and R4 are identical or different and each is a cycloaliphatic or araliphatic radical or especially an aliphatic radical and Z is an alkali metal atom.

The alcohol VI may be present in stoichiometric amount or in excess over the starting material II, preferably in an amount of from 10 to 100 moles, especially from 30 to 50 moles, of alcohol VI per mole of starting material II. The alkali metal alcoholate is preferably used in stoichiometric amount or in excess, advantageously in an amount of from 2 to 5, preferably from 2.2 to 3, equivalents of starting material V per mole of starting material II. The presence of water is neither essential nor advantageous but water may be added, in the form of a mixture, for example in the form of the moist starting material II; for example, from 0 to 50 per cent by weight of water, based on starting material II, may be present.

Preferred alkali metal alcoholates V and alcohols VI are those where R3 and R4 are different or, preferably, identical and each is cycloalkyl of 5 to 7 carbon atoms, aralkyl of 7 to 12 carbon atoms or especially alkyl of 1 to 10 carbon atoms, R3 may also be H --(R55-0)),-Z and/or R4 may also be (R5O)nH, where R3 and R4 preferably only differ in respect of the terminal atoms Z and H, R5 is an aliphatic radical, preferably alkylene of 2 to 6 carbon atoms, n is an integer, preferably 4, 3, 2 and especially 1, and Z is lithium, potassium or especially sodium. The above radicals may furthermore be substituted by groups which are inert under the reaction conditions, e.g. alkyl or alkoxy of I to 4 carbon atoms.

Examples of suitable alcohols VI are methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec.-butyl alcohol, tert.-butyl alcohol, pentyl alcohol, pentyl-2 alcohol, pentyl-3 alcohol, n-hexyl alcohol, n-heptyl alcohol, n-octyl alcohol, n-nonyl alcohol, n-decyl alcohol, 2 ethylhexyl alcohol, 2,2,6-trimethyl-n-heptyl alcohol, 2-ethylpentyl alcohol, 3 ethylpentyl alcohol, 2,3-dimethyl-n-butyl alcohol, 2,2-dimethyl-n-butyl alcohol, 2 methylpentyl alcohol, 3-methylpentyl alcohol, 2,2,4-trimethylheptyl alcohol, 2methylheptyl alcohol, 3-methylheptyl alcohol, 4-methylheptyl alcohol, 3-ethylhexyl alcohol, 2,2-dimethylhexyl alcohol, 2,3-dimethylhexyl alcohol, 2,4-dimethylhexyl alcohol, 2,5-dimethylhexyl alcohol, 3,3-dimethylhexyl alcohol, 3,4-dimethylhexyl alcohol, 2-methyl-3-ethylpentyl alcohol, 3-methyl-3-ethylpentyl alcohol, 2,2,3trimethylpentyl alcohol, 2,2,4-trimethylpentyl alcohol, 2,3,3-trimethylpentyl alcohol, 2,3,4-trimethylpentyl alcohol and 2,2,3,3-tetramethylbutyl alcohol; cyclohexanol, benzyl alcohol, ethylene glycol, triglycol, tetraglycol, propane-1,3diol, butane-1,4-diol, propane-1,2-diol, neopentyl glycol, 2,4-pentylene glycol, 2,3butylene glycol, hexane- I 6-diol, phenylbutanol, methylcyclohexanol, cyclopentanol, cycloheptanol, phenylethyl alcohol, phenylpropanol and cyclooctanol; methyl-, ethyl-, n-propyl-, isopropyl-, n-butyl-, iso-butyl-, sec.-butyl and tert.-butyl-ethylene glycol; methyl-, ethyl-, n-propyl-, isopropyl-, n-butyl-, isobutyl-, sec.-butyl- and tert.-butyl-propylene glycol; methyl-, ethyl-, n-propyl-, isopropyl-, n-butyl-, isobutyl-, sec.-butyl and tert.-butyldiglycol and corresponding triglycol ethers and tetraglycol ethers.

Preferred alcohols are methanol, ethanol, n- and iso-propanol, n- and isobutanol, n- and iso-pentanol, n- and iso-hexanol, 2-ethyl-hexanol, n- and isooctanol and cyclohexanol.

Suitable alkali metal alcoholates are the lithium alcoholates, potassium alcoholates and, especially, sodium alcoholates of the above alcohols VI, preferably of those alcohols VI described above as being preferred.

The halide III or IV is added preferably in the stoichiometric amount or in excess over the starting material II, preferably in an amount of from I to 2 moles, especially from 0.01 to 1.4 moles, per mole of starting material II. Preferred halides III and IV are those where the individual radicals R1 and R2 may be identical or different and each is alkyl of 1 to 8 carbon atoms or is phenyl and the above radicals may be substituted by I or 2 alkyl each of I to 4 carbon atoms, or one or two nitro, and X is bromine or preferably chlorine.

Examples of sulfonic acid halides III are methyl-, ethyl-, n-propyl-, isopropyl-, n-butyl-, isobutyl-, sec.-butyl- and tert.-butyl-sulfonyl chloride; 2methylbenzenesulfonyl chloride, 3-methylbenzene sulfonyl chloride, 4methylbenzenesulfonyl chloride, 2,3-dimethylbenzenesulfonyl chloride, 3,4dimethylbenzenesulfonyl chloride, 2,6-dimethylbenzenesulfonyl chloride, 3,5dimethylbenzenesulfonyl chloride, 2-ethylbenzenesulfonyl chloride, 3ethylbenzenesulfonyl chloride, 4-ethylbenzenesulfonyl chloride, 2,3diethylbenzenesulfonyl chloride, 3,4-diethylbenzenesulfonyl chloride, 2,6diethylbenzenesulfonyl chloride, 3,5-diethylbenzenesulfonyl chloride, 2nitrobenzenesulfonyl chloride, 3-nitrobenzenesulfonyl chloride, 4nitrobenzenesulfonyl chloride and benzenesulfonyl chloride; and the corresponding bromides; benzenesulfonyl chloride, toluenesulfonyl chloride which is substituted in the o-, m- or p-position, 3,4- and 2,4-dimethylbenzenesulfonyl chloride, nitrobenzenesulfonyl chloride which is substituted in the o-, m- or pposition, ethylbenzenesulfonyl chloride which is substituted in the o-, m- or pposition, methylsulfonyl chloride, ethylsulfonyl chloride, propylsulfonyl chloride, butylsulfonyl chloride, pentylsulfonyl chloride, hexylsulfonyl chloride and octylsulfonyl chloride are preferred.

Examples of phosphoric acid ester halides IV are phosphoric acid dimethyl ester chloride, diethyl ester chloride, di-n-propyl ester chloride, diisopropyl ester chloride, di-n-butyl ester chloride, diisobutyl ester chloride, di-sec.-butyl ester chloride, di-tert.-butyl ester chloride, dipentyl ester chloride, di-n-hexyl ester chloride, di-n-heptyl ester chloride and di-n-octyl ester chloride, phosphoric acid di-2,6-dimethylphenyl ester chloride, di-o-tolyl ester chloride, di-m-tolyl ester chloride, di-p-tolyl ester chloride, di-o-xylyl ester chloride, di-m-xylyl ester chloride and di-p-xylyl ester chloride, the ester group preferably being in the m-position to one of the two methyl groups in the case of the di-xylyl esters, phosphoric acid di- a- naphthyl ester chloride, di-p-naphthyl ester chloride and diphenyl ester chloride, and the corresponding bromides. Phosphoric acid dimethyl ester chloride, diethyl ester chloride, di-n- or di-isopropyl ester chloride, dibutyl ester chloride, dipentyl ester chloride and dioctyl ester chloride are preferred.

The basic compound used may be the alcoholate V itself, in the above preferred amounts, advantageously using from 2 to 5 equivalents, based on starting material II. However, it is also possible, and more advantageous, to add a further basic compound, as a rule an alkali metal compound, alkaline earth metal compound or tertiary amine. Advantageous amounts are from 0.2 to 4 equivalents of the basic compound per mole of starting material II. Advantageous alkali metal compounds and alkaline earth metal compounds are the hydroxides, oxides and carbonates. Examples of suitable basic compounds are potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, lithium carbonate, calcium hydroxide, baiium oxide, magnesium hydroxide and calcium carbonate.

Suitable tertiary amines are aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic amines, preferably those where the organic radicals are identical or different alkyls of 1 to 12 carbon atoms, phenyl, aralkyls of 7 to 12 carbon atoms and/or cycloalkyls of 5 to 7 carbon atoms and mononuclear or dinuclear Nheterocyclic radicals, each nucleus being of 5 or 6 members. Examples of suitable tertiary amines are trimethylamine, triethylamine, tri-n-propylamine, tri-nbutylamine, tripentylamine, tri-n-heptylamine, tri-octylamine, trinonylamine, tridecylamine, triundecylamine, tridodecylamine and tri-n-hexylamine; dimethyl diethyl-, di-n-propyl- and di-n-butyl-cyclohexylamine and correspondingly N,Ndisubstituted anilines, benzylamines and o-, m- and p-toluidines; triphenylamine, tribenzylamine, tri-(phenylethyl)-amine, tri-(phenylpropyl)-amine and tri (phenylbutyl)-amine; triphenylamine which is monosubstituted in the 2,3,- or 4position or disubstituted in the 2,4-, 2,3-, 2,6-, 2,5-, 3,4- or 3,5-position by methyl, in each phenyl ring; correspondingly N-monosubstituted pyrrolidine, pyrazolidine, imidazolidine, hexamethyleneimine, piperidine and morpholine; 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, 2,4-dimethylpyridine 2,6-dimethylpyridine, 2,4,6-trimethylpyridine and especially pyridine; quinoline, pyridazine, pyrimidine and pyrazine; and corresponding amines having 3 of the above radicals, some or all of which are however different from one another, e.g. N-ethyl-N-methylaniline, Nmethyl-N,N-diethylamine, N,N-dicyclohexyl-N-methylamine, N - methyl - N ethyl - N - n - propylamine; trimethylamine, triethylamine, tri-n-propylamine, tributylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, triundecylamine, tridodecylamine, tricyclohexylamine, dimethylcyclohexylamine, cyclohexyldiethylamine and cyclohexyldibutylamine are preferred.

The reaction may be carried out as follows: a mixture of the starting materials, the compounds III or IV, the alcohol and the basic compound, is reacted for from 2 to 10 hours at the reaction temperature. In a preferred embodiment, the starting material II is suspended in the alcohol and the alkali metal alcoholate is added with vigorous stirring at from 0 to 1000C, advantageously at room temperature. The starting material III or IV is run into the well-mixed suspension, advantageously at from 0 to 300 C, and stirring is continued, advantageously for from 30 to 60 minutes, whilst adding alkali metal alcoholate, advantageously at from 0 to 400 C.

In a further preferred embodiment, a mixture of alkali metal alcoholate and basic compound, e.g. tertiary amine, is added to the vigorously stirred starting material II in the alcohol. The compounds III or IV are then added and finally the remaining amount of alcoholate is introduced.

It is preferred to add the alkali metal alcoholate in several portions, especially in 2 portions. Advantageously, part of the alcoholate is introduced initially and the remainder, advantageously from 55 to 65 per cent by weight of the total alcoholate, is added after the compounds III or IV, advantageously from 30 to 60 minutes after these have been introduced.

In another advantageous embodiment, the starting material II, alcohol and basic compound are mixed, the compound III or IV is then added and finally the total amount of the alkali metal alcoholate is introduced.

Advantageously, in all these cases, the time between the start of the addition of the basic compound and/or the addition of the first portion of alkali metal alcoholate and the start of the addition of the compound III or IV is from 40 to 300 minutes, the time for addition of compound III or IV is from 20 to 120 minutes, the time from the end of the addition of the compound III or IV to the start of the addition of the total amount or remaining proportion of alcoholate is from 30 to 120 minutes, the time for addition of this total amount or remaining proportion of alcoholate is from 10 to 300 minutes and the duration of the remainder of the reaction is from 10 to 90 minutes.

After the reaction, the end product may be isolated in the conventional manner, e.g. by steam-distilling the alcohol. The alcohol can advantageously be distilled off under atmospheric pressure or reduced pressure, after which water is added to the distillation residue and the mixture is heated once more. After cooling, the end product crystallises out and can be isolated by filtration. The filter residue is washed with an aqueous ammonia solution.

The preferred method, however, is to add acid to the reaction mixture, after completion of the reaction, advantageously in the course of from 5 to 50 minutes, at from 0 to 1000C, preferably from 20 to 600 C, under atmospheric or superatmospheric pressure, batchwise or continuously. The treatment is advantageously carried out with from I to 3, especially from 1.2 to 1.5, equivalents of acid, based on starting material II. Inorganic or organic acids may be used.

Instead of monobasic acids, equivalent amounts of polybasic acids may be employed. Examples of suitable acids are hydrochloric acid, hydrobromic acid, hydriodic acid, perchloric acid, sulfuric acid, phosphoric acid, nitric acid and carbonic acid; sulfonic acids, e.g. benzenesulfonic acid and p-toluene-sulfonic acid; aliphatic carboxylic acids, e.g. oxalic acid, formic acid, acetic acid, propionic acid, butyric acid and isobutyric acid: preferred acids are sulfuric acid, hydrochloric acid, hydrobromic acid, perchloric acid, phosphoric acid, nitric acid, formic acid and acetic acid.

After the treatment with acid, the end product can be isolated from the mixture by conventional methods, e.g. by precipitation with water. In a preferred method of working up, the alcohol is driven off in steam, whereupon the end product precipitates, after cooling, as a yellow crystalline compound. In another preferred method of working up, the alcohol is distilled off under atmospheric pressure or reduced pressure. The residue is then precipitated with ice water.

After filtering, the filter residue is advantageously washed with an aqueous ammoniacal solution and then with water.

The naphtholactam which may be manufactured by the process of the invention is a valuable starting material for drugs and optical brighteners and especially for dyes for polyacrylonitrile and polyesters. Regarding its use, reference may be made to the above publications and to the following patents: German Laidopen Applications DOS 2,309,612, 2,341,657, 2,036,504 and 1,931,789, German Published Application DAS 1,917,456 and German Patents 1,444,660, 1,225,326 and 2,237,372.

In the examples which follow, parts are by weight.

EXAMPLE 1 256 parts of naphthalic acid hydroxyimide are suspended in 1,500 parts of methanol. 195 parts of 30 per cent strength by weight sodium methylate solution in methanol and 30 parts of triethylamine are added at room temperature, with vigorous stirring. After 30 minutes, 244 parts of benzenesulfonyl chloride are added, with vigorous stirring. To complete the reaction, the mixture is then stirred for 90 minutes. 300 parts of a 30 percent strength by weight solution of sodium methylate in methanol are added to the suspension obtained, at 200 C, with slight cooling. The mixture is then stirred for 30 minutes, after which the pH is brought to 2-3 with hydrochloric acid. The methanol is distilled off. The residue is suspended in ice water, filtered off, washed with I per cent strength by weight aqueous ammonia solution and then with water, and is dried. 181 parts (89 /n of theory) of naphtholactam of melting point 18-1810C are obtained.

EXAMPLE 2 356 parts of naphthalic acid hydroxyimide (containing 100 parts of water) are suspended in 1,500 parts of methanol. The reaction and working-up are carried out as described in Example 1. 173 parts (85% of theory) of naphtholactam, of melting point 179--181"C, are obtained.

EXAMPLE 3 256 parts of naphthalic acid hydroxyimide are suspended in 2,000 parts of methanol. 195 parts of a 30 per cent strength by weight sodium methylate solution and 31 parts of triethylamine are added at room temperature. The reaction and working-up are carried out as described in Example 1. 185 parts (91 /" of theory) of naphtholactam, of melting point 180--182"C, are obtained.

EXAMPLE 4 256 parts of naphthalic acid hydroxyimide are suspended in 1,800 parts of isobutanol. 250 parts of a 30 percent strength by weight sodium methylate solution are added to the mixture at room temperature. 244 parts of benzenesulfonyl chloride are added in the course of 90 minutes at 250C, with vigorous stirring. The mixture is then stirred for 60 minutes, after which 280 parts of sodium methylate solution are added at 250C. The pH is brought to 2-3 with sulfuric acid and the isobutanol is driven off in super-heated steam. After cooling, the mixture is filtered and the filter residue is washed with I per cent strength by weight aqueous methylamine solution and then with, and is dried. 177 parts (870/, of theory) of naphtholactam of melting point 180--181"C are obtained.

EXAMPLES 5 to 8 The reaction and working-up are carried out as described in Example 4.

Yield of Yield naphtholactam Melting point Example Alcohol (parts) ( /" of theory) ( C) 5 Pentanol 177 87 179--180 6 2-Ethylhexanol 175 86 177 179 7 Cyclohexanol 169 83 176-179 8 n-Octanol 165 81 179-181 EXAMPLE 9 256 parts of naphthalic acid hydroxyimide are suspended in 2,200 parts of methanol. 195 parts of 30 per cent strength sodium methylate solution and 30 parts of triethylamine are added with vigorous stirring. After 30 minutes, 160 parts of methanesulfonyl chloride are added at from 0 to l00C. After a further 90 minutes, 300 parts of 30 per cent strength by weight sodium methylate solution are added at the same temperature. The mixture is then stirred for 15 minutes and acidified with sulfuric acid, the methanol is distilled off, 2,000 parts of ice water are added to the mixture and the product is filtered off, washed with 3% strength aqueous ethanolamine solution and then with water, and dried. 180 parts (89% of theory) of naphtholactam of melting point 180--1810C are obtained.

EXAMPLE 10 The reaction and working-up are carried out as described in Example 9.

Instead of methanesulfonyl chloride, 266 parts of p-toluenesulfonyl chloride are used. 177 parts (87 /" of theory) of naphtholactam of melting point 179--1810C are obtained.

EXAMPLE 11 The reaction and working-up are carried out as described in Example 9.

Instead of methanesulfonyl chloride, 266 parts of o-p-toluenesulfonyl chloride are used. 179 parts (88 /" of theory) of naphtholactam of melting point 180--1810C are obtained.

EXAMPLE 12 The reaction and working-up are carried out as described in Example 9.

Instead of methanesulfonyl chloride, 250 parts of phosphoric acid diethyl ester chloride are used. 175 parts (86 /" of theory) of naphtholactam of melting point 18182"C are obtained.

EXAMPLE 13 The reaction and working-up are carried out as described in Example 9.

Instead of methanesulfonyl chloride, 295 parts of octylsulfonyl chloride are used.

169 parts (83 /n of theory) of naphtholactam of melting point 177--1800C are obtained.

EXAMPLE 14 5.4 parts of sodium hydroxide are dissolved in 150 parts of methanol. 25.6 parts of naphthalic acid hydroxyimide are introduced, with vigorous stirring. 25 parts of toluenesulfonyl chloride are added at 250C. The mixture is then stirred for 60 minutes; a further 31.5 parts of sodium methylate are added at 200C. After 30 minutes, the mixture is brought to pH 2-3 with sulfuric acid. The methanol is driven off in steam. The residue is filtered and the product is washed first with 1 per cent strength N-methylpiperazine solution and then with water, and is dried. 163 parts (80% of theory) of naphtholactam of melting point 178--1810C are obtained.

EXAMPLE 15 25.6 parts of naphthalic acid hydroxyimide are introduced into a mixture of 180 parts of isobutanol and 13.2 parts of triethylamine. 25 parts of o-toluenesulfonyl chloride are added at from 20 to 300 C. The mixture is then stirred for 60 minutes; 47 parts of sodium methylate are added at 200 C. The reaction and working-up are carried out as described in Example 14. 181 parts (89% of theory) of naphtholactam of melting point 180--1820C are obtained.

EXAMPLE 16 The reaction and working up are carried out as described in Example 15.

Instead of triethylamine, 11 parts of pyridine are used. 183 parts (900/, of theory) of naphtholactam of melting point 180--181"C are obtained.

EXAMPLE 17 The reaction and working-up are carried out as described in Example 15.

Instead of triethylamine, 28 parts of dicyclohexylmethylamine are used. 179 parts (88 / of theory) of naphtholactam of melting point 179--181"C are obtained.

EXAMPLE 18 The reaction and working-up are carried out as described in Example 15.

Instead of triethylamine, 21 parts of diethylbenzylamine are used. 163 parts (80% of theory) of naphtholactam of melting point 177--1800C are obtained.

EXAMPLE 19 The reaction and working-up are carried out as described in Example 14.

Instead of sodium hydroxide, 7.5 parts of potassium hydroxide are used. 161 parts (79% of theory) of naphtholactam of melting point 178--1810C are obtained.

EXAMPLE 20 26.6 parts of naphthalic acid hydroxyimide are suspended in 140 parts of methanol. 23.8 parts of 30 per cent strength by weight sodium methylate are added, with vigorous stirring. After 30 minutes, 23.8 parts of benzenesulfonyl chloride are added at 200 C. After a further 90 minutes, 24.5 parts of 30 per cent strength by weight sodium methylate solution are added at from 10 to 200 C.</RT are added, with vigorous stirring. After 30 minutes, 25 parts of benzenesulfonyl chloride are added at 200C. At this temperature. 2.4 parts of triethylamine are added, and after 15 minutes a further 3.5 parts of benzenesulfonyl chloride are introduced. After 45 minutes, 30 parts of sodium methylate are added to the mixture in the course of 30 minutes. After stirring for 20 minutes, the mixture is acidified, the methanol is distilled off and the residue is precipitated with ice water.

The product is filtered off and washed with 3 per cent strength aqueous ammonia solution and then with water. After drying 22.5 parts (93.5 /,, of theory) of naphtholactam of melting point 178--181"C are obtained.

WHAT WE CLAIM IS: 1. A process for the manufacture of naphtholactam, of the formula

wherein naphthalic acid hydroxyimide, of the formula

is reacted with an alkali metal alcoholate in the presence of a sulfonic acid halide of the formula

or of a phosphoric acid ester halide of the formula

where the individual radicals R2 are identical or different and Rt and the radicals R2 are each an aliphatic or aromatic radical and X is halogen, in the presence of an alcohol and of a basic compound.

2. A process as claimed in claim 1, wherein the reaction is carried out with from 10 to 100 moles of alcohol per mole of starting material II.

3. A process as claimed in claim 1 or 2, wherein the reaction is carried out with from 2 to 5 equivalents of alkali metal alcoholate per mole of starting material II.

4. A process as claimed in any of claims 1 to 3, wherein the reaction is carried out with the lithium alcoholate, potassium alcoholate or sodium alcoholate of methanol, ethanol, n- or iso-propanol, n- or iso-butanol, n- or iso-pentanol, n- or iso-hexanol, 2-ethylhexanol, n- or iso-octanol or cyclohexanol as the alkali metal alcoholate.

5. A process as claimed in any of claims I to 4, wherein the reaction is carried out with from 1 to 2 moles of halide III or IV per mole of starting material II.

6. A process as claimed in any of claims I to 5, wherein the basic compound is separate from the alkali metal alcoholate used as a starting material.

7. A process as claimed in any of claims I to 5, wherein the reaction is carried out with an alkali metal compound, alkaline earth metal compound or tertiary amine as the basic compound using from 0.2 to 4 equivalents of basic compound per mole of starting material II.

8. A process as claimed in any of claims 1 to 7, wherein the reaction is carried

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (13)

**WARNING** start of CLMS field may overlap end of DESC **. are added, with vigorous stirring. After 30 minutes, 25 parts of benzenesulfonyl chloride are added at 200C. At this temperature. 2.4 parts of triethylamine are added, and after 15 minutes a further 3.5 parts of benzenesulfonyl chloride are introduced. After 45 minutes, 30 parts of sodium methylate are added to the mixture in the course of 30 minutes. After stirring for 20 minutes, the mixture is acidified, the methanol is distilled off and the residue is precipitated with ice water. The product is filtered off and washed with 3 per cent strength aqueous ammonia solution and then with water. After drying 22.5 parts (93.5 /,, of theory) of naphtholactam of melting point 178--181"C are obtained. WHAT WE CLAIM IS:

1. A process for the manufacture of naphtholactam, of the formula

wherein naphthalic acid hydroxyimide, of the formula

is reacted with an alkali metal alcoholate in the presence of a sulfonic acid halide of the formula

or of a phosphoric acid ester halide of the formula

where the individual radicals R2 are identical or different and Rt and the radicals R2 are each an aliphatic or aromatic radical and X is halogen, in the presence of an alcohol and of a basic compound.

2. A process as claimed in claim 1, wherein the reaction is carried out with from 10 to 100 moles of alcohol per mole of starting material II.

3. A process as claimed in claim 1 or 2, wherein the reaction is carried out with from 2 to 5 equivalents of alkali metal alcoholate per mole of starting material II.

4. A process as claimed in any of claims 1 to 3, wherein the reaction is carried out with the lithium alcoholate, potassium alcoholate or sodium alcoholate of methanol, ethanol, n- or iso-propanol, n- or iso-butanol, n- or iso-pentanol, n- or iso-hexanol, 2-ethylhexanol, n- or iso-octanol or cyclohexanol as the alkali metal alcoholate.

5. A process as claimed in any of claims I to 4, wherein the reaction is carried out with from 1 to 2 moles of halide III or IV per mole of starting material II.

6. A process as claimed in any of claims I to 5, wherein the basic compound is separate from the alkali metal alcoholate used as a starting material.

7. A process as claimed in any of claims I to 5, wherein the reaction is carried out with an alkali metal compound, alkaline earth metal compound or tertiary amine as the basic compound using from 0.2 to 4 equivalents of basic compound per mole of starting material II.

8. A process as claimed in any of claims 1 to 7, wherein the reaction is carried

out with stepwise addition of ingredients under conditions such that the time between the start of the addition of the basic compound and/or the addition of the first portion of alkali metal alcoholate and the start of the addition of the compound III or IV is from 40 to 300 minutes, the time for addition of compound III or IV is from 20 to 120 minutes, the time from the end of the addition of the compound III or IV to the start of addition of the total amount of remaining proportion of alcoholate is from 30 to 120 minutes, the time for addition of this total amount or remaining proportion of alcoholate is from 10 to 300 minutes and the duration of the remainder of the reaction is from 10 to 90 minutes.

9. A process as claimed in claim 8, wherein the alcoholate is added in the two portions, from 35 to 45 per cent in the first portion and the remainder in the second portion.

10. A process as claimed in any of claims 1 to 7, wherein after completion of the reaction, the reaction mixture is treated with from I to 3 equivalents of acid, based on starting material II, in the course of from 5 to 50 minutes at from 0 to 100"C.

11. A process for the manufacture of naphtholactam carried out substantiallv as described in any of the foregoing Examples.

12. Naphtholactam when obtained by the process claimed in any of the claims 1 to 11.

13. Dyes, drugs and optical brighteners when made from naphtholactam claimed in claim 12.