DE1184769B - Process for the preparation of omega-acylamino-carboxylic acid esters - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: C 07 c

German class: 12 q- 6/01

Number: 1184 769

File number: B 72101IV b / 12 q

Filing date: May 30, 1963

Opening day: January 7, 1965

w-Acylamino-carboxylic acid esters are known. To the process of German Patent 975 633 are N-acylated lactams, which one by action organic carboxylic acids can be obtained on lactams, reacted with alcohols. After the procedure According to German patent specification 942 864, lactams in acidic alcoholic solution are converted into aminocarboxylic acid esters reacted, and then an acyl group is converted into the amino group by the action of acylating Agents introduced in the presence of acid-binding agents. It is also known that lactams are produced by Action of mineral acid to give the corresponding aminocarboxylic acids or their salts split (cf. Houben - Weyl, Methods of Organic Chemistry, 4th Edition, Vol. 11, Part 2 [1958], P. 565). Finally, in the German patent specification 948 973, the implementation of lactams with Described haloformic acid esters to O-alkyl lactimes.

It has now been found that ω-acylaminocarboxylic acid esters obtained when lactams with esters of monobasic or dibasic unsubstituted ones aliphatic carboxylic acids, aromatic carboxylic acids, araliphatic carboxylic acids or with esters of halogenated fatty acids containing at least 2 carbon atoms contain, preferably under slight to moderate excess pressure and / or under the radical formation converting favorable reaction conditions.

The reaction can be carried out using the example of the reaction of caprolactam with ethyl acetate as follows reproduce:

CH ₂ - (CH ₂ ) ₄ - CO + CH ₃ • CO ■ OC ₂ H ₅

-NH-

> CH ₃ CO - NH - (CHa) ₅ - COOC ₂ H ₅

Lactams are especially those with five to thirteen ring members, such as pyrrolidone, <5-valerolactam, piperidone, caprolactam, oenanthlactam, capryllactam and laurolactam are suitable. But it can also be other lactams, e.g. B. C-alkyl caprolactams or Aryl lactams, e.g. B. Oxindole (Indoxyl), use.

Particularly suitable esters are those which are derived from low molecular weight alcohols. As examples may be mentioned methyl formate, ethyl formate ^ butyl formate ^ benzyl formate, Methyl acetate, ethyl acetate, isopropyl acetate, phenyl propionate, Ethyl 2-ethylhexanoate, ethyl benzoate, ethyl phenylacetate, dimethyl oxalate, Succinic acid diethyl ester and adipic acid diethyl ester.

Method of manufacture

of ω-acylamino-carboxylic acid esters

Applicant:

Aniline & Soda Factory in Baden

Aktiengesellschaft, Ludwigshafen / Rhein

Named as inventor:

Dr. Karl-Heinz König, Ludwigshafen / Rhine

The reaction is carried out at a temperature of about 20 to 280 ⁰ C, in particular from 80 to 190 ⁰ C. With regard to the temperature range, in many cases an application becomes a

moderate overpressure, e.g. B. up to 3 atm, required. But it can also be beneficial to the procedure to be carried out at a higher pressure than corresponds to the vapor pressure of the reaction components, z. B. up to about 50 at.

One can run the procedure at room temperature or just above it, especially if one applies radical-forming conditions, e.g. B. irradiation with active light, e.g. B. of wavelength 150 up to 450 Γημ, or with high-energy rays, such as B.

Alpha, beta, gamma (or X-ray) rays, UV, neutron or proton radiation or additive of peroxides, e.g. B. benzoyl peroxide, ascaridol, di-tert-butyl peroxide, or azo compounds, e.g. B. Azodiisobutyronitrile.

If no radical formers are present, it is advisable to run the process at an elevated temperature,

z. B. between 60 and 280 ⁰ C, in particular at 80 to 190 ⁰ C to perform.

The reaction can also be influenced catalytically, z. B. It is accelerated if you use Ansolvo acids (defined in the sense of Meerwein, such as z. B. in F. Hein, chemical coordination theory) adds. Examples of such catalysts are: Boron trifluoride as an etherate or tetrahydrofuranate, zinc chloride, aluminum chloride, aluminum alcoholates, Titanium tetrachloride.

The reactants are in approximately stoichiometric amounts or with excesses of one or other component, usually the ester component

nent, applied up to 150%. The excess is recovered in the work-up. Unless one Adding catalysts, they are used in amounts of 0.1

409 767/380

up to 5% j based on the deficit of the reaction component, added to the reaction mixture. To carry out the reaction, the reactants are mixed in any order and either mixed with a radical generator and / or heated. The reaction generally increases 3 to 25 hours to complete. The process can also be carried out continuously, e.g. B. by passing the mixed reactants through a heated tube.

The ω-acylaminocarboxylic acid esters obtainable by the process serve as intermediate products.

example 1

115 parts by weight of ε-caprolactam and 80 parts by weight Ameisensäueräthylester are heated for 18 hours in a closed vessel at 18O ⁰ C. One (71% of theory equivalent) obtained from the resulting reaction mixture in the distillation next to 26 parts by weight of non-consumed ε-caprolactam (Kp. _12mm 138 to 140 ⁰ C) 133 parts by weight of co-formylamino-capronsäureäthylester from Kp. _{O 4157-160} ⁰ C; n _D = 1.460.

The unreacted ε-caprolactam can be used again for the reaction.

Example 2

The mixture is heated 42 parts by weight of pyrrolidone and 65 parts by weight of ethyl formate 8 to 10 hours at 160 to 18O ⁰ C. In the subsequent distillation of the resulting reaction mixture is obtained in addition to unreacted Ameisensäureäthylesterund Porrylidon 108 parts by weight of y-formylamino-buttersäreäthylesters from Kp. _{0> 8132} to 134 ° C (yield 68% of theory); nf = 1.464.

Example3

57 parts by weight of ε-caprolactam and 190 parts by weight of ethyl acetate are kept at 190 ° C. for 16 hours with the addition of 2 ml of boron trifluoride etherate. In addition to a forerun consisting of ethyl acetate and ε-caprolactam, the distillation of the reaction mixture gives 123 parts by weight (corresponding to 61% of theory) of ethyl ω-acetylaminocaproate of boiling point ₄ 145 to 147 ° C .;

nff = 1.461.

Claims (4)

Patent claims: 1. A process for the preparation of ω- acylaminocarboxylic acid esters, characterized in that lactams with esters of monobasic or dibasic unsubstituted aliphatic carboxylic acids, aromatic carboxylic acids, araliphatic carboxylic acids or with esters of halogenated fatty acids which contain at least 2 carbon atoms, at about 20 to 280 ° C, preferably under slight to moderate excess pressure, e.g. B. up to about 50 at, and / or under the reaction conditions favoring radical formation. 2. The method according to claim 1, characterized in that one carries out the reaction at temperatures from 80 to 190 ⁰ C. 3. The method according to claim 1 and 2, characterized in that the reaction is carried out in the presence of Ansolvo Acids. 4. The method according to claim 1 and 2, characterized in that the reaction is carried out in the presence of radical-forming substances or under the influence of high-energy radiation performs. 409 767/380 12.64 © Bundesdruckerei Berlin