DE1668072A1 - Process for the production of novel enamides - Google Patents

Description

FARBENFABRIKENBAYERAG Fu / Bi LEVERKUSEN. «. Towok _{January 1968} Patent department

Process for the production of novel enamides

The present invention relates to a process for the preparation of novel enamides, characterized in that that one üycloketimine of the general formula

< ^CH

wherein

R is an optionally substituted straight-chain or branched optionally unsaturated aliphatic radical having up to 20 carbon atoms, R is an optionally substituted cycloalkyl radical having 4-7 ring members, R is also an optionally substituted phenyl or aralkyl radical, and

η means an integer from 1-13,

with at least the equimolar amount of an acid anhydride of the formula

R ¹ - ^
R ¹ - ^

where R ^{1 has} the same meaning as R ,

optionally in the presence of inert organic solvents

Le A 11 224 _-Λ - 1 109830/2048

Ί668072

is reacted in the temperature range from about -50 to about + 20O ⁰ C and then the reaction solution is optionally subjected to fractional distillation under reduced pressure.

Although it is known from German patent specification 1 129 946, to prepare vinyl-substituted tertiary acid amides starting from aldimines and acetic anhydride. For splitting off acetic acid from the N - (^ C-acetoxyethyl) -N-alkyl-acetamide formed as a primary adduct however, the addition of at least a molar amount of a base, e.g. triethylamine, is necessary; otherwise takes place mainly cleavage to N-alkylacetamide.

As from the following example of the reaction between Cyclohexylidenmethylamln and acetic anhydride

/ -a CH _x -CO ", 0-CO-CH,> 50 ° C

(Wn-ch, + ^y > ο ->

(HCH,> 0) (χ  _CH

^N - ^/ ° CH ₃ -CO W ^N _N / ^on 3 -CH ₃ COOH

.CH ₃ "CO-CH ₃

II

the production of enamides according to the invention also takes place in two steps, the anhydride primarily being attached to the CN double bond of the cycloketimine and being split off from the carboxylic acid adduct in the second stage. If the reaction of the two components above 50 ⁰ C, then both reaction can

Le. A 11 224 _{Λ Λ} - 2 109830/2048

% ί on steps are performed at the same time. In order to achieve better yields, however, it is advisable to first carry out the addition at low temperature and then to carry out the cleavage by increasing the temperature without isolating the adduct I beforehand, advantageously in the course of a distillation.

Surprisingly, the cleavage according to the invention takes place here the adducts of cycloketimines and carboxylic acid anhydrides above 50 ° C extremely easily under exclusive ^ Formation of the enamides II without the need to add a base.

AIc optionally unsaturated alkyl radicals are those with up to 20 carbon atoms, preferably 1 to 12 carbon atoms, very particularly preferably those with 1 to 5 carbon atoms, which can contain up to 2 double or one triple bond. The alkyl radicals can optionally be substituted by halogen (preferably fluorine, chlorine, bromine), CN, nitro, sulfonic acid esters, lower alkoxy with up to 6 carbon atoms, lower acyl (radical of a lower aliphatic carboxylic acid with up to 3 carbon atoms), phenyl. The phenyl radical can of course carry the abovementioned substituents one or more times.

Oycloalkyl radicals are those with 4 to 7 (preferably 5 to 7) ring members, which are optionally replaced by halogen (preferably ilaor, chlorine, bromine), lower alkyl, lower alkoxy, sulfonic acid ester, CN, nitro are substituted.

Le A 11 224 - 3 - IAD OFUGlNAL

109830/2048

Ala aralkyl radicals are ß-phenylethyl and preferably benzyl mentioned, which may optionally be substituted by the substituents mentioned for the cycloalkyl radical.

Cycloketimines of the above general formula may be exemplified as starting compounds for the process according to the invention the following compounds named: cyclobutylidenemethylamine, cyclopentylidenebutylamine, Gy el opentyl idencycl ohexylamine, Cyclopentylideneaniline, Cyclopentyliden-p-chloroaniline, Cyclopentyliden-p-anisidine, Methylcyclohexylidenebutylamine, cyelohexylidenemethylcyclohexylamine, Cyclohexylidene-p-chloroaniline, Cyclohexylidene-p-anisidine, cyclohexylidene-p-toluidine, cyclohexylidene-p-carbethoxyaniline, Cycloheptylidenebutylamine, cycloheptylidenecyclohexylamine, Cyclododecylidenebutylamine, cyclododecylidenecyclohexylamine, cyclopentadecylidenebutylamine. The following may be mentioned as particularly preferred representatives: cyclopentylidenemethylamine, cyclohexylidenemethylamine, cyclohexylidenecyclohexylamine, Cyclohexylidene aniline.

Any anhydrides can be used to react with these cycloketimines of monocarboxylic acids such as butyric acid, ethoxyacetic acid, 4-chlorobutyric acid, p-tolylacetic acid, acrylic acid, methacrylic acid, Propyne (2) carboxylic acid (i), tindecylic acid, undecene (1) acid (II), Stearic acid, cyclopentanecarboxylic acid, cyclohexenecarboxylic acid, Benzoic acid, p-chlorobenzoic acid, o-methoxybenzoic acid, p-toluic acid can be used; acetic anhydride is particularly preferred used.

Le A 11 224 - 4 -

109830/2048

I b 6 Ö Ü 7 2

The reaction conditions can vary within certain limits depending on the choice of starting components. In general, equimolar amounts of cycloketimines and acid anhydride are used. However, it can be advantageous to use a small excess of acid anhydride (up to 1.1 moles per mole of cycloketime). The reaction in the temperature range of about • - to about +200 ⁰ C, preferably from about 0 to about 140 ⁰ C, performed • IG. It is preferably carried out in the absence of solvents; if necessary, however, inert solvents such as petroleum ether, benzene, toluene, chloroform, acetonitrile can be used. To isolate the products of the process, the carboxylic acid formed at the same time must be separated off. This operation is preferably carried out under reduced pressure.

The compounds prepared according to the invention correspond to the general formula

^ c - n:

/ COR

(CH ₂ ) _n

* R

in which R and R ¹ have the meanings given above and η is an integer from 1 to 13, preferably from 2 to 5.

These are generally oils that can be distilled under normal conditions are persistent. They make valuable intermediates for the manufacture of lubricants, plastics and Textile auxiliaries.

Le A 11 224 - 5 -

109830/20 * 8

Q 1öböU72

Example 1.

To 337 g (3.3 mol) of acetic anhydride are added within 15 minutes with stirring, 291 g (3 mol) of cyclopentylidenemethylamine

Q = N-CH,

added dropwise. By external cooling the temperature to 35 ⁰ C. When the addition is complete, the mixture is stirred for another 30 minutes and the contents of the flask are then fractionated over an effective silver jacket column. After a forerun of acetic acid and acetic anhydride proceed at 106-107 ⁰ C and a pressure of 13 Torr 358 g (86% of theory) of N-methyl-N-cyclopenten-1-yl-acetamide

O-

/ COCH ₃

N
^X CH

20th
as a colorless oil over; η = 1.4941. There is practically no residue.

Analysis for C ₈ H ₁₃ NO (139.2) Calculated: C 69.0 H 9.4 N 10.0 O 11.5

Found: 69.1 9.5 10.2 11.8

Le Ά 11 224 - 6 -

109830/204 «originally inspected

I b 6 Ö Ü 7

Example 2

377 g of N-methyl-N-cyclohexen-1-yl-acetamide

/ CO-CH ₃ 3

can be obtained in the manner described in Example 1 from 333 g (3 mol) Cyclohexylidenemethylamine and 337 g (3.3 mol) of acetic anhydride were obtained. ·

20 Yield: 82 %; Boiling point 131 ^° C. at 23 torr; η = 1.4904.

Analysis for C ₉ H ₁₅ NO (153, 2) calc. : C 70.6 H 9.8 N 9.1 O 10.5

Found: 70, 6 10.0 9, 1 10.6

Example 3

A mixture of 173 g (1 mole) cyclohexanonanil

and 112 g (1, 1 mol) of acetic anhydride is heated slowly entering to exothermic at 12O ⁰ C the reaction. After the reaction has subsided, stirring is continued for a further 2 hours at 100 ^° C. and the contents of the flask are then fractionated. After a first run of acetic acid go at 120-130 ° C and a pressure of about 0.04 Torr 189 g (88% of theory) N-phenyl

- 7 -109830/2048

S 1668U72

N-cyclohexen-1-yl acetamide

/ COCH
^U 6 5

20th
as an almost colorless oil over: n = 1.5609.

Analysis: for C ₁₄ H ₁₇ NO (215, 3) calc. : C 78,2 H 7,9 N 6,5 O 7,4

Found: 77.5 7.9 6.7 7.6

Example 4

Cycloheptylidenepropyl prepared from cycloheptanone and propylamine

= NC ₃ H ₇

20th
(Bp. 96-97 ° C at 13 Torr; η = 1.4740; calculated: N 9, 2; found: N 9, 1) is reacted with acetic anhydride as described in Example 1. After the acetic acid formed in the reaction has been separated off, 81% of theory are N-propyl-N-cyclohepten-1-yl-acetamide

CO-CH "

A, 11 ²² 4 - 8 -

109830/2048

obtained from boiling point 153 to 154 ° C at a pressure of 13 torr;

20th
n ^ = 1.4893,

Analysis for C _1O H _O1 NO (195, 3) Ber. : C 73.8 H 10.8 N 7.2

Found: 74.1 11.1 7.4

Example 5

To 22.4 g (0.22 mol) of acetic anhydride, 38.6 g (0.2 mol) of cycloheptylidenecyclohexylamine ^{are added at 90 ° C.}

O-O

added dropwise and the mixture ^{stirred at 90 0} C for 4 hours. After the acetic acid formed during the reaction has been deducted, 31 g (66% of theory) of N-cyclohexyl-N-cyclopefeten-1-ylacetamide ^{are obtained at 140 to 142 ° C. and a pressure of 0.06 torr}

/ CO-CH

20th
as an almost colorless oil; η = 1.5407.

Analysis for C ₁ -H ₀ -NO (235, 4) calc. : C 76.7 H 10.7 N 6.0

Found: 76.6 11.1 6.2

Le A 11 224 - 9 -

109830/2048

Claims (2)

Claims 1. Process for the preparation of novel enamides, characterized in that one uses cycloketimines of the general formula -C = N-R wherein R is an optionally substituted straight-chain or branched optionally unsaturated aliphatic radical with up to 20 carbon atoms, R for one optionally substituted cycloalkyl radical with 4-7 Ring members, R is also an optionally substituted phenyl or aralkyl radical, and η means an integer from 1-13, with at least the equimolar amount of an acid anhydride of the general formula where R ^{1 has} the same meaning as R, optionally reacted in the presence of inert organic solvents in the temperature range from about -50 to about +200 ⁰ C and then subjecting the reaction solution, optionally under reduced pressure, to fractional distillation. 2. The method according to claim 1, characterized in that the cycloketimine and a carboxylic acid anhydride are initially used Le A 11 224 - 10 - 10 9830/2048 ^0RIGiNÄL! ^ ^{? EGTED} Ί668072 0 ° "to 140 ⁰ C is reacted and the resulting primary adduct cleaves without intermediate isolation in the temperature range of about -50 to about 200 ⁰ C in enamide and carboxylic acid-. Compounds of the formula -COR • C - N: CH wherein R and R ^{1 have} the meaning given in claim 1 and ti is an integer from 1 to 13. Le A 11 224 - 11 - 109830/2048