DE1259871B - Process for the preparation of N-chloroformylcarbamic acid esters - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

C07c

German KL: 12 ο -17/01

Number: 1 259 871

File number: B 75264IV b / 12 ο

Filing date: February 1, 1964

Open date: February 1, 1968

It is known from American Chemical Journal, Vol. 19 (1897), p. 344, that by reaction of alkyl carbamates unsubstituted on the nitrogen atom with phosgene in the presence of Benzene and pyridine Ν, Ν'-dicarbalkoxyureas obtained. Two molecules of alkyl carbamic acid react with a molecule of phosgene to form an N.N'-disubstituted urea molecule. The conversion of carbamic acid esters unsubstituted on the nitrogen atom is also carried out without Addition of tertiary aromatic amines to a mixture of carbonyl diurethane, N-chloroformyl carbamic acid esters and allophane ethers. Uniform end products, in particular N-chloroformylcarbamic acid esters could not be produced in good yield in this way.

In contrast, it has now been found that N-chloroformylcarbamic acid esters of the general formula

R - N - COOR '
COCl

wherein R is an alkyl, alkenyl, alkynyl or aralkyl radical and R 'is optionally through Bromine, chlorine, nitro, alkoxy or phenoxy groups substituted alkyl, alkenyl, alkynyl, aryl, Cycloalkyl, aralkyl or alkaryl radical is obtained when a carbamic acid ester is used Method of manufacture

of N-chloroformyl carbamic acid esters

Applicant:

Aniline & Soda Factory in Baden

Aktiengesellschaft, 6700 Ludwigshafen

Named as inventor:

Dr. Günter Scheuerer, 6700 Ludwigshafen

general formula

R-NH

COOR '

wherein R and R 'have the meaning given above, with phosgene in the presence of a tertiary aromatic amine, the amine expediently being used at least in stoichiometric amounts, based on the carbamic acid ester to be reacted, in the temperature range from 10 to 150 ^° C. in the presence of an inert one organic solvent converts.

The reaction can be carried out using ethyl N-methylcarbamate, phosgene and dimethylaniline represented by the following reaction equation:

CH ₃ - NH - COOC ₂ H ₅ + COCl ₂ +

> CH ₃ -N- COOC ₂ H ₅ +

COCl

HCl

The carbamic acid esters of the general formula II used as starting materials are derived from primary aliphatic or araliphatic monoamines. Preferred amines are monoalkylamines, the alkyl group of which contains 1 to 14 carbon atoms, e.g. B. methyl, ethyl, butyl, 2-ethylhexylamine, Propyl, isopropyl, n-, iso- and sec-butyl-, isoamyl-, octyl- or dodecylamine. But you can also use carbamic acid esters as starting materials, which are derived from primary monoamines, in which the aliphatic radical contains a C - C double or triple bond, e.g. B. Allyl-. Propargylamine or undecyleneamine, or in which the alkyl radical is substituted by a phenyl radical, such as α- and ß-phenethylamine, benzylamine and 2-amino-1-phenylpropane.

The alcohol component in the carbamic acid esters used as starting materials of the general Formula II are preferably derived from alkanols having 1 to 14 carbon atoms, alkenols with 3 to 8 carbon atoms, alkynols with 3 to 8 carbon atoms, cycloalkanol with 5

709 747/568

up to 12 carbon atoms, aralkanols with 7 to 12 carbon atoms, phenols or naphthols away. The alcohols, phenols or naphthols mentioned can also be substituted. As possible Substituents are e.g. B. bromine, chlorine, nitro, alkoxy or phenoxy groups mentioned. For example The following carbamic acid esters can be used: N-methyl, N-ethyl, N-butyl, N- (2-ethylhexyl) - or N-phenethylcarbamic acid methyl ester, the corresponding -ethyl-, -butyl-, -2-ethylhexyl-, -jS-chloroethyl-, -allyl-, -propargyl-, -2-methylbutyn- (l) -yl- (3) -, -4-methyl-pentyn- (l) -yl- (3) -ester, N-methylcarbamic acid phenyl-, -p-chlorophenyl-, -m-nitrophenyl-, -p-toluyl- or -a-naphthyl ester.

For the purposes of this invention, tertiary aromatic amines are to be understood as meaning amines which are am Nitrogen atom carry at least one aryl radical, z. B. dimethylaniline, diethylaniline or methyldiphenylamine, or in which the nitrogen atom is a member of an aromatic six-membered ring, z. B. pyridine or quinoline.

The reaction is carried out in the presence of an inert organic solvent and / or suspension medium. As a solution and or or Hydrocarbons such as petroleum ether, benzene, toluene and xylene are also suitable suspending agents Chlorinated hydrocarbons, such as ethylene chloride, chloroform or carbon tetrachloride, and ethers, such as Diethyl ether, dioxane or tetrahydrofuran. These substances can, for. B. expedient in amounts of 25 up to 95 percent by weight, based on the reaction mixture, can be used. One can also Use mixtures of these solvents.

You can use the carbamic acid esters, which correspond to the general formula II, the phosgene and use the tertiary aromatic amine in a molar ratio of 1: 1: 1. However, it is useful Use phosgene and the amine in excess. Good results are obtained if you look at every mole Carbamic acid esters 1.05 to 2.3 moles of phosgene and 1.2 to 2.4 moles of amine are used in the reaction.

The reaction is expediently carried out in such a way that either the carbamate, mixed with the amine, is added to a phosgene solution or the procedure is reversed. The reaction temperature and time depend both on the tertiary amine chosen and on the starting carbamate. The reaction is carried out in the temperature range of 10 to 150 ⁰ C.

For work-up, the reaction mixture, which consists of the solution of the chloroformyl carbamate and The organic layer consists of precipitated amine chlorohydrate, poured onto water and / or ice separated, washed to remove excess amine with dilute mineral acid and after After evaporation of the solvent, the end product is purified by distillation or crystallization.

Some of the new N-substituted chloroformylcarbamic acid esters obtainable by the process are liquid, partly crystalline compounds, insoluble in water, soluble in most organic solvents and show reactive behavior similar to carbamic acid chlorides. The liquids can generally be distilled without decomposition under reduced pressure and boil higher than the starting compounds, while the crystalline derivatives of this series from inert solvents can be recrystallized and melts lower than the starting compound.

The new compounds are valuable intermediates for the manufacture of pharmaceuticals, Pesticides, plant protection products and dyes.

The parts mentioned in the examples are parts by weight.

example 1

A mixture of 31 parts of ethyl N-methylcarbamate and 28.5 parts of pyridine is slowly added at room temperature to a solution of 32.5 parts of phosgene in 400 parts of carbon tetrachloride. After the addition has ended, the mixture is stirred at room temperature for 2 hours and then at 60 ° C. for 2 hours. The reaction mixture is poured onto ice water, the organic layer is separated off, washed with 2η hydrochloric acid and water and dried with sodium sulfate. After distilling off the solvent, 46 parts of N - chloroformyl - N - methylcarbamidsäureäthylester which boils below 20 torr at 101-102 ⁰ C; Refractive index nf = 1.4512. The yield is 92.8% of theory, based on the ethyl N-methylcarbamate used.

If only 17 parts are used instead of 28.5 parts of pyridine, otherwise the procedure given above is used Thus, only 28 parts of N-chloroformyl-N-methylcarbamic acid ethyl ester are obtained, accordingly a yield of only 56.6% of theory, based on the ethyl N-methylcarbamate used.

Example 2

A mixture of 31 parts of N-methylcarbamic acid ethyl ester and 43.5 parts of dimethylaniline is slowly added to 32.5 parts of phosgene, dissolved in 218 parts of toluene, with stirring at room temperature, and the mixture is stirred for 2 hours at room temperature and 2 hours at 6O ⁰ C. After the work-up carried out in Example 1, 34.2 parts of the ethyl N-chloroformyl-N-methylcarbamate described in Example 1 are obtained. The yield is 69% of theory, based on the ethyl N-methylcarbamate used.

If the dimethylaniline is replaced by the equivalent amount of diethylaniline or quinoline, the result is one yields from 50 to 45% of theory.

B e "i s ρ i e 1 3

To 32.5 parts of phosgene, dissolved in 218 parts of toluene, 31 parts are added at room temperature Ethyl N-methylcarbamate and 28.5 parts of pyridine were slowly added, followed by 8 hours stirred at this temperature. After the work-up described in Example 1 are 38 parts of N-methyl-N-chloroformylcarbamic acid ethyl ester were obtained. The yield is 76.6% of theory, based on the applied N-methylcarbamic acid ethyl ester.

Example «4

To a solution of 31 parts of N-methylcarbamic acid ethyl ester and 43.5 parts of dimethylaniin in

130 parts of toluene are slowly added at room temperature a solution of 32.5 parts of phosgene in 87 parts of toluene and stirred for 2 hours at room temperature and 2 hours at 6OC after. After work-up, as described in Example 1, is obtained 29.7 parts of N-methyl-N-chloroformylcarbamic acid ethyl ester. The yield is 60% of theory, based on the ethyl N-methylcarbamate used.

Example 5

IO

To a solution of 33 parts of phosgene in 218 parts of toluene are added at room temperature a mixture of 26.7 parts of N-Methylcarbamidsäuremethylester and 28.5 parts of pyridine and then stirred for 2 hours at room temperature and 2 hours at 60 'C after. After the work-up described in Example 1, 29.5 parts of methyl N-methyl-N-chloroformylcarbamic acid with a boiling point of 91 to 93 ° C. at 25 Torr and a refractive index nf = 1.4568 are obtained. The yield is 65% of theory, based on the methyl N-methylcarbamate used.

In a corresponding way one gets from

30.9 parts of methyl N - ethyl carbamate; 34 parts of methyl N - chloroformyl - N - ethyl carbamate; Boiling point 96 to 98 ^° C. at 28 torr; Refractive index nf = 1.4519. The yield is 69 ⁰ A) of theory, based on N-applied Äthylcarbamidsäuremethylester.

35.1 parts of N - ethylcarbamic acid ethyl ester 33 parts of N - chloroformyl - N - ethylcarbamic acid ethyl ester; Boiling point 100 to 102 ° C at 13 torr; Refractive index nf = 1.4442. The yield is 61.5% of theory, based on the ethyl N-ethylcarbamate used.

58 parts of N - (/ ^ - phenethyl) -carbamic acid ethyl ester 66 parts of N-chloroformyl-Ni / i-phenäthyO-carbamic acid ethyl ester; Boiling point 113 to 115 ° C. at 0.1 torr; Refractive index nf = 1.5136. The yield is 86.5% of theory, based on the N - (/ 3'-phenethyl) carbamic acid ethyl ester used.

34.5 parts of N-methylcarbamic acid allyl ester 39 parts of N-chloroformyl-N-methylcarbamic acid allyl ester; Boiling point 56 to 58 ° C at 0.3 torr; Refractive index nf = 1.4685. The yield is 73.5% of theory, based on the allyl N-methylcarbamate used.

46.5 parts of N-methylcarbamic acid (4-methylpentyn-1-yl-3) ester 54 parts of N-chloroformyl-N-methylcarbamic acid (4-methylpentyn-yl-3) ester; Boiling point 82 to 84 ° C at 0.3 torr; Refractive index nf = 1.4678. The yield is 83% of theory, based on the N-methylcarbamic acid (4-methyl-pentyn-1-yl-3) ester used.

43.5 parts of ethyl N-butylcarbamate; 47 parts of ethyl N-chloroformyl-N-butylcarbamate; Boiling point 125 to 127 ° C at 22 torr; Refractive index nf = 1.4459. The yield is 76% of theory, based on the ethyl N-butylcarbamate used.

38 parts of N-methylcarbamic acid (butyn-1-yl-3) ester, 43 parts of N-chloroformyl-N-methylcarbamic acid (butyn-1-yl-3) ester; Boiling point 56 to 58 C at 0.1 torr. The yield is 75% of theory, based on applied N-methylcarbamic acid (butin-l-yl-3) ester.

47 parts of N-butylcarbamic acid allyl ester 42 parts of N-chloroformyl-N-butylcarbamic acid allyl ester; Boiling point 67 ³ C at 0.1 torr; Refractive index nf = 1.4590. The yield is 64% of theory, based on the allyl N-butylcarbamate used.

39 parts of ethyl N-propylcarbamate 41 parts of ethyl N-chloroformyl-N-propylcarbamate; Boiling point 110 to 111 ⁰ C at 13 torr; Refractive index nf = 1.4461. The yield is 72% of theory, based on the ethyl N-propylcarbamate used.

34 parts of N-isopropylcarbamic acid methyl ester 36 parts of N-chloroformyl-N-isopropylcarbamic acid methyl ester; Boiling point 87 ° C at 16 torr; Refractive index nf = 1.4423. The yield is 66 ^° A) of theory, based on the methyl N-isopropylcarbamate used.

Example 6

To a solution of 44 parts of phosgene in 87 parts of toluene at room temperature, a solution of 40.5 parts of N- (2-ethylhexyl) -carbamidsäureäthylester and 38 parts of pyridine in 150 parts of dioxane, and then stirred for 2 hours at 40 ⁰ C and 4 Hours at 6O ⁰ C after. Following the procedure described in Example 1, working up, 30 parts of N - chloroformyl - N - (2 - ethylhexyl) - carbamidsäureäthylester of boiling point 89 to 93 ⁰ C at 0.3 Torr, corresponding to a yield of 56.5% of theory, based on applied N- (2-ÄthyIhexyl) -carbamidsäureäthylester.

Analogously one obtains from

37 parts of N-methylcarbamic acid p-chlorophenyl ester 36 parts of N-chloroformyl-N-methylcarbamic acid p-chlorophenyl ester; Boiling point 113 to 114 ° C at 0.01 torr; Melting point 40 to 42 ° C. The yield is 73% of theory, based on the applied N-methylcarbamic acid p-chloiphcinl ester.

27.8 parts of N-methylcarbamic acid fl- chloroethyl ester 31 parts of N-chloroformyl-N-methylcarbamic acid jö-chloroethyl ester; Boiling point 127 to 129 ° C at 10 torr; Refractive index nf = --- 1.4786. The yield is 77.1% of theory, based on the N-methylcarbamic acid /: i-chloroethyl ester used.

Example 7

To a solution of 33 parts of phosgene in 800 parts of carbon tetrachloride are added at room temperature a mixture of 56 parts of N-methylcarbamate-2-ethylhexyl and 28.5 parts of pyridine and stirred for 2 hours at room temperature and 2 hours at 6O ⁰ C to. After similar work-up as in Example 1, 62 parts of N-chloroformyl-N-methylcarbamic acid-2-ethylhexyl ester are obtained; Boiling point 90 to 92 ° C at 0.1 torr; Refractive index nf = 1.4582. The yield is 83.2% of theory, based on the 2-ethylhexyl N-methylcarbamic acid used.

Example 8

To a solution of 88 parts of phosgene in 175 parts Toluene is added at room temperature

Solution naphthyl N-Methylcarbamidsäurea and 76 parts of pyridine in 300 parts of dioxane, and then stirred for 2 hours at room temperature, 2 hours at 40 ° C and 2 hours at 60 ⁰ C. After working up as described in Example 1 from 80.5 parts described , 113 parts remain behind after evaporation of the solvent of an approximately 90% crude product which is recrystallized from cyclohexane at 45 ⁰ C. 83 parts of N-chloroformyl-N-methylcarbamic acid-a-naphthyl ester with a melting point of 51 to 52 ° C. are obtained. The compound can also be ^{distilled at 162 to 165 °} C. below 0.2 torr. The yield is 79% of theory, based on the N-methylcarbamic acid a-naphthyl ester used.

Example 9

A mixture of 31 parts is added to a solution of 32.5 parts of phosgene in 218 parts of toluene N-methylcarbamic acid ethyl ester and 28.5 parts of pvridine added slowly at room temperature. The reaction mixture is then heated to 105.degree heated and stirred for 2 hours at this temperature.

After the work-up described in Example 1, 30 parts of that described in Example 1 are obtained N-chloroformyl-N-methylcarbamic acid ethyl ester was obtained. The yield is 60.4% based on used N-methylcarbamic acid ethyl ester.

Claims (1)

Claim: Process for the preparation of N-chloroformylcarbamic acid esters the general formula R —N —COOR '
COCl wherein R is an alkyl, alkenyl, alkynyl or aralkyl radical and R 'is optionally through Bromine, chlorine, nitro, alkoxy or phenoxy groups substituted alkyl, alkenyl, alkynyl, Aryl, cycloalkyl, aralkyl or alkaryl radical, characterized in that that one has a carbamic acid ester of the general formula R - NH - COOR ' wherein R and R 'have the aforementioned meaning, with phosgene in the presence of a tertiary aromatic amine, the amine expediently at least in stoichiometric amounts, based on the carbamic acid ester to be reacted, is used in the temperature range of 10 to 150 C in the presence of an inert organic solvent. Considered publications:
American Chemical Journal, Vol. 19, 1897, p. 344; Houben - Weyl, Methods of Organic Chemistry, Vol. 8, 1952, p. 149. 709 747/568 1.68 © Bundesdruckerei Berlin