DE1166771B - Process for the preparation of N-substituted ketenimine dicarboxylic acid derivatives - Google Patents

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FEDERAL REPUBLIC OF GERMANY GERMAN WWW PATENT OFFICE Internat. Class: C 07 c

EDITORIAL

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German KL: 12 ο-22

B 67148 IVb / 12 ο

May 8, 1962

April 2, 1964

It is known that N-phenyl-keteniminedicarboxylic acid diethyl ester obtained when N-phenyl-triphenyl-phosphinimine with diethyl ketene dicarboxylate implemented (Helvetica Chimica Acta, Vol. 4 [1921], p. 887).

It has now been found that N-substituted ketenimine dicarboxylic acid derivatives are advantageously obtained, when using N-substituted thiocarboxamides of the general formula

NH-C-CH

-X

(I)

in which R is a mono- to trivalent organic radical and X and Y are a carbon ester group, while η is an integer from 1 to 3, reacts with an inorganic acid halide and treats the intermediate product thus obtainable with a hydrogen halide-releasing agent.

Process for the production of

N-substituted

Ketenimine dicarboxylic acid derivatives

Applicant:

Aniline & Soda Factory in Baden

Aktiengesellschaft, Ludwigshafen / Rhein

Named as inventor:

Dr. Peter Dimroth, Ludwigshafen / Rhine

The implementation of methane tricarboxylic acid diethyl ester thioanilide with phosphorus pentachloride and the subsequent elimination of hydrogen chloride can be formulate as follows:

C ₆ H ₅ -NH-C-CH

COOC ₂ H ₅
COOC ₂ H ₅

+ PCl ₅

-PSCl ₃ , -HCl

C ₆ H ₅ -NH-C = C
Cl

COOC ₂ H ₅
COOC ₂ H ₅

C ₆ H ₅ -N = C-CH

Cl

COOC ₂ H ₅
COOC ₂ H ₅

C ₆ H ₅ -N = C =

COOC ₂ H ₅
COOC ₂ H ₅

The starting materials of the general formula I are prepared in a customary manner by reacting isothiocyanates (or mustard oils) of the general formula

R (N = C = S) _n

in which R and η have the meaning given above, prepared with a malonic ester. Suitable isothiocyanates II either have a hydrocarbon structure, apart from the isothiocyanate groups, or carry substituents which are inert under the reaction conditions, such as alkoxy, carbon ester, nitrile, alkyl mercapto and nitro groups or aromatically bonded halogen atoms. Suitable isothiocyanates are, for example: methyl isothiocyanate, butyl isothiocyanate, stearyl isothiocyanate, γ - methoxy - propyl - isothiocyanate, carboethoxymethyl isothiocyanate, β - cyanoethyl isothiocyanate, γ - methyl mercapto - propyl isothiocyanate, γ - methyl mercapto - propyl isothiocyanate, γ - methyl mercapto - isloothiocyanate, cycloothiocyanate, cycloothiocyanate, cycloothiocyanate, cycloothiocyanate , Benzyl - isothiocyanate, ρ - methoxybenzyl - isothiocyanate, β - phenylethyl - isothiocyanate, phenyl - isothiocyanate, tolyl - isothiocyanate, naphthyl - isothiocyanate, 4-chlorophenyl isothiocyanate, 2-chloro-4-methylphenyl - isothiocyanate, 4 , 3-carboethoxyphenyl isothiocyanate, 4-nitrophenyl isothiocyanate, 2 - methyl - 4 - cyano - phenyl isothiocyanate, ^ - carbonamidophenyl isothiocyanate, ρ - phenylene - di - isothiocyanate, p, p '- diphenyl - di - isothiocyanate, hexamethylene - di - isothiocyanate, tris (γ-isothiocyanato-propyl) amine.

The preferred malonic acid esters are derived from aliphatic alcohols with up to 8 carbon

409 557/541

atoms off. Of the malonic acid derivatives which contain carbonamide groups, those are preferred which are substituted on the carbonamide nitrogen by two aliphatic radicals having up to 4 carbon atoms or by an aromatic radical having 6 to 10 carbon atoms. Specifically, for example, malonic acid diethyl ester, malonic acid dibutyl ester, malonic acid di-2-ethylhexyl ester, malonic acid di (β- methoxyethyl) ester, malonic acid di-benzyl ester, malonic acid di-cyclohexyl ester may be mentioned.

The starting materials of the formula I do not need to be used as such, they can rather be used even without prior isolation in the form of the solutions implemented in the reaction of the Isocyanates II can be obtained with the malonic esters. Of the suitable inorganic acid chlorides are, for example, phosphorus pentachloride, phosphorus tribromide, phosphorus oxychloride, thionyl chloride, thionyl bromide and phosgene mentioned. The preferred inorganic acid halides are thionyl chloride and phosgene. The acid halides are used in an amount such that each isothiocyanate group 1 molecule of the acid halide is omitted. An excess, for example 10 to 100 mole percent, However, it doesn't do any harm.

The reaction of the starting material I with the inorganic acid chloride is expediently carried out in an inert solvent or suspension medium. For example, benzene, trichlorethylene and nitrobenzene are useful. In some cases, e.g. B. when using phosgene, it is advisable to add a small amount, for example 2 to 10 percent by weight, based on the thiocarboxamide, of an activator. Suitable activators include pyridine, tributylamine, dimethylformamide, dibutylformamide, N-methylpyrrolidone and N-ethylcaprolactam. The use of an activator accelerates the reaction considerably. You can work within a very wide temperature range. If an activator is also used, the reaction can be carried out, for example, at room temperature or at a reduced temperature, while temperatures between 30 and 120 ^° C. are recommended in the absence of an activator.

The intermediate products, which are obtained by reacting the starting materials I with inorganic acid halides, are then treated with an agent which splits off hydrogen halide and which is inert towards the reaction products. Suitable agents which split off hydrogen halide are, for example, alkali and alkaline earth oxides, hydroxides, amides, hydrides, carbonates and hydrogen carbonates, and also tertiary amines. The agents which split off hydrogen halide are advantageously used in stoichiometric amounts or in a slight excess. The elimination of hydrogen halide is advantageously carried out at temperatures between +10 and + 6O ⁰ C.

The inorganic constituents or the amine hydrohalides are extracted from the reaction mixture mechanically separated. The reaction products are obtained from the solutions by evaporation. the If desired, substances can be purified by recrystallization.

The N-substituted ketenimine dicarboxylic acid derivatives obtainable by the process are valuable Intermediate products for the manufacture of dyes. You also got into plastics chemistry Importance, especially if they contain the ketenimine group several times in the molecule.

The parts mentioned in the following examples are parts by weight. They relate to the parts of the room how grams to cubic centimeters.

example 1

590 parts of methane tricarboxylic acid diethyl ester thioanilide

NH - C - CH

COOC ₂ H ₅ COOC ₂ H ₅

are dissolved in 2500 parts of dry benzene. 300 parts are passed into the solution at room temperature Phosgene and finally a solution of 10 parts of dimethylformamide in 100 parts of benzene over the course of 4 hours. The mixture is stirred for a further 4 hours at room temperature. 300 parts of benzene are then distilled off and 250 parts of triethylamine are gradually added Residue. The mixture is stirred for 12 hours at room temperature. The precipitated triethylamine hydrochloride is removed by suction and washes it out with 500 parts of benzene. The washing liquid is combined with the filtrate and this concentrated to a quarter of the original volume under reduced pressure. It separates the N-phenyl-ketenimine-dicarboxylic acid diethyl ester

/ COQC ₂ H ₅

_{C == C} /

^X COOC ₂ Hs

in the form of colorless crystals, which are filtered off with suction and washed with a mixture of 10OTeiJen benzene and 200 parts of cyclohexane. In this way 367 parts of the pure compound with a melting point of 81 to 83 ^° C. are obtained.

The product, dissolved in benzene, gives an oily hydrochloride on introduction of hydrogen chloride.

If, under otherwise identical conditions, 160 parts of magnesium oxide are used in place of the triethylamine as an agent which splits off hydrogen halide, 264 parts of the reaction product are obtained.

Example 2

One carries 110 parts of sodium methoxide and 320 parts of malonic acid diethyl ester in a 35OOTeile trockenesToluol, the mixture heated to 50 ⁰ C and distilled under reduced pressure, 500 parts of toluene from. 270 parts of phenyl isothiocyanate are then added to the cooled solution over the course of 2 hours. The mixture is stirred for 6 hours, 125 parts of glacial acetic acid are added, the mixture is shaken out with 1000 parts of cold water and 300 parts of toluene are distilled off from the organic layer.

300 parts of phosgene are introduced into the distillation residue and a solution of 10 Tejjen of dimethylformamide in 100 parts of toluene little by little to. The mixture is stirred for 4 hours,

200 parts of toluene are distilled off under reduced pressure, 250 parts of triethylamine are added to the mixture and stir it for 6 hours at room temperature and 2 hours at 40 ° C. The deposited solid constituents are removed by suction and washed out with benzene. The combined filtrates are evaporated to 800 parts of the room. On cooling, 326 parts of N-phenyl-ketenimine-dicarboxylic acid diethyl ester crystallize the end. _

Example 3

590 parts of methane tricarboxylic acid diethyl ester thioanilide, 600 parts of trichlorethylene and 500 parts of thionyl chloride are refluxed for 6 hours. The solvent and excess thionyl chloride are distilled off under reduced pressure and 1200 parts of benzene and 250 parts of triethylamine are added to the residue. The mixture is stirred for 8 hours at room temperature and 2 hours at 4O ⁰ C.

The procedure described in Example 1 is followed and 328 parts of N-phenyl-ketenimine-dicarboxylic acid diethyl ester are obtained.

Example 4

320 parts of malonic acid diethyl ester, 1600 parts

dry tetrahydrofuran and 50 parts sodium powder are stirred until the metallic sodium disappeared. 242 parts of 1,5-naphthylene di-isothiocyanate are added to the solution

within 2 hours. The mixture is stirred for 12 hours. Then 115 parts of glacial acetic acid are added added, the solvent is distilled off under reduced pressure, 1,800 parts of benzene are added to the Residue, the mixture is stirred for two hours and the solid constituents which have separated out are filtered off with suction. In the solution that made the connection

C ₂ H ₅ OC
O

) CH — C —NH

NH-C-CH (

- COOC ₂ H ₅ COOC ₂ H ₅

300 parts of phosgene are passed in and a solution of 10 parts of dimethylformamide in 100 parts of benzene is added to the mixture over the course of 7 hours. It is stirred for 4 hours at room temperature and for 2 hours at 4O ⁰ C. Then are added 250 parts of triethylamine, and the mixture is stirred for a further 12 hours at room temperature and for 2 hours at 35 ° C. The solid constituents which have separated out are filtered off with suction, washed with benzene and the combined filtrates are evaporated to one third of the original volume under reduced pressure. 211 parts of the connection divide

COOC ₂ H ₅ V

) C = C =
COOC ₂ H /

C = C =

N = C = C

COOC ₂ H ₅
COOC ₂ H ₅

from F. = 109 ⁰ C (decomposition). The product yields a dihydrochloride from F. 122 ° C (decomposition).

cyanate 338 parts of p-chlorophenyl isothiocyanate and receives 296 parts of N- (p-chlorophenyl) -ketenimine-

_. -rc dicarboxylic acid diethyl ester of m.p. 116 ⁰ C (Zer-

for example:> Settlement). The compound forms a hydrochloride

One works as described in Example 4, sets 50 of the MP 154 ° C (decomposition), but instead of 1,5-naphthylene-di-isothio-

Claims (3)

Patent claims: 1. A process for the preparation of N-substituted ketenimine dicarboxylic acid derivatives, characterized in that one N-substituted thiocarboxamides of the general formula So NH-C-CHi (I) / n in which R is a mono- to trivalent organic radical and X and Y are a carbon ester group, while η is an integer from 1 to 3, reacts with an inorganic acid halide and treats the intermediate product thus obtainable with a hydrogen halide-releasing agent. 2. The method according to claim 1, characterized in that phosgene or thionyl chloride used as an inorganic acid halide. 3. The method according to any one of claims 1 and 2, characterized in that in Presence of an activator such as pyridine, tributylamine, dimethylformamide, dibutylformamide, N-methylpyrrolidone and N-ethylcaprolactam, is working.