SU212158A1 - METHOD OF OBTAINING N-SUBSTITUTED IMIDES OF MALEIC ACID - Google Patents

Description

This invention relates to the cyclization of an imide of maleic acid and one hundred N-substituted.

It is known to produce N-ethyl imide maleic acid by heating the corresponding amide at 200 ° C.

A method is proposed for the preparation of M-mixed; enry imnda maleic acid of the general formula

And .- With - SOH

NR

II H - C - CO

where R is alkyl, haloalkyl, alkene, phenyl, alkylphenyl, nigrophenyl, which consists in heating the N-substituted maleic acid amides of the total formula

0

n - s - cf

II NHR H - C - SOOS

where the values of R are the same as above, at a temperature of 80-200 ° C in the presence of an acidic catalyst, for example sulfuric acid, chlorosulfonic acid, phos1:) organic, organophosphoric, which are adverse reactions in an organic solvent, and for example toluene, benzene .

The catalyst taken in the amount of 0.01 - 20% by weight of the acid. The yield of the target product is about 80 7o.

Example I. 50 parts of N-o-hlbrphenylmaleamic acid and 215 parts of xylene are heated and stirred at reflux in a Diaa-Stark discharger for b / h hour. By the end of this period, 1 hour (about 25% of the theoretical amount) of water accumulates in the collection apparatus. The hot mixture is filtered and an excess amount of petroleum ether with a boil is added to the cooled filtrate. 40-60 ° C. The precipitate contains an insignificant amount of N-o-chlorophenyl maleimide and is significantly larger in proportion to the amount of unreacted N-0-chlorophenyl maleamic acid.

The process described in Example 1 was then repeated several times, in each case applying 25 parts of M-o-chlorophenyl maleamic acid in a specially selected solvent.

Each process is stimulated by the addition of a catalyst. After heating, the mixture is filtered to remove insoluble by-products and then an excess amount of petroleum ether is added to the cooling filtrate. 40-60 ° C. The resulting precipitate is removed, washed and dried, determining the yield of the imide.

The yield, melting point and purity of N-0-chlorophenyl maleimide are summarized in table. one

(pure N-o-chlorophenyl maleimide has a melting point of 74-75 ° C).

Note: The amount of contamination has been determined by infrared analysis. Thinner A - toluene (108h.); thinner B - xylene (108 hours); diluent B - chlorobenzene (125 h);

diluent G - a mixture of toluene with benzene, t. Kip. 99C (110 hours); diluent D - a mixture of toluene with benzene, t. Kip. (110 hours).

A comparison of examples 3 and 4 with examples 10 and 11 illustrates the advantages associated with the use of phosphorus-containing acids, in order to reduce the yield of insoluble by-products.

Example 17. 63.7 parts of o-chloroaniline was added dropwise with stirring to a solution of 49 parts of maleic anhydride in 216 parts of toluene, and the mixture was stirred for 16 hours. Then 2 parts / g-toluene sulfonic acid is added, the mixture is stirred and heated under reflux for 2 hours in a Dean-Stark apparatus. By the end of this period, 8h accumulated in the apparatus collection. water (about 90% of the theoretical amount).

17 parts of the toluene-insoluble material are separated by filtration, and an excess amount of petroleum ether boiling in the range of 40-60 ° C is added to the filtrate. The precipitated solid was found to consist of 90 parts of a slightly contaminated N-o-chlorophenyl maleimide having a m.p. 55-56C. The brilliant product is dissolved in benzene and the solution is passed through alumina (alumina). So, get 84 hours of product with so pl. 65.5-66.5 ° C.

Similar results can be obtained with the use of N-o-bromophenyl maleamic acid and N-l-fluorophenyl maleimic acid.

Example 18. 25 parts of M-o-pitrophenyl maleamic acid and 108 parts of toluene are heated under the action of a reflux condenser and stirred in a Dean-Stark apparatus for 4 hours together with 1 part of l-toluenesulfonic acid. TO

The end of this time accumulated 1.7 hours of water. An excess amount of petroleum ether is added to the mixture. 60-80 ° C, the precipitated crude N-o-nitrophenyl maleimide is filtered off, washed with a saturated solution of patric bicarbonate and dried in vacuum. The dried product is dissolved

B Benzene, is passed through alumina (oxide

aluminum) and again precipitated, pouring the solution into gasoline. Obtain 11.1 parts of N-o-nitrophenylmaleimide, so pl. 131 - 132 ° C.

The results are similar in the case of the use of M -. / And-nitrophenyl- and N-n-nitrophenyl maleamic acid.

Example 19. The process is repeated according to the procedure described in Example 18, using 25 parts of N-phenyl-maleamine

acid, 108 parts of xylene and one part of the α-toluene sulfonic acid.

Heating is continued for 5 hours, after which 2 parts of water are ground. After removal of insoluble by-products, precipitation is carried out by

pouring into pegrol ether with t. kip. 60-80 ° C; 12.6 parts of N-phenylmaleimide, m.p. 88 ° C. Similar results can be obtained with

using N-a-naphthyl, M-p-naphthyl, N-1-fluorenyl- and N-4-fluorenyl maleamic acid, N-phenyl-2-chloromaleamic acid and N-phenyl pitraconoamic acid. Example 20. The process is repeated, respectively. Example 21. 25 parts of L-butyl-maleamic acid and 108 parts of xylene are stirred and heated under reflux in a Dean-Stark apparatus in the presence of traces of the product Topanol O as a polymerization inhibitor. After 6 hours, accumulated 1.8 hours. water. An additional 100 parts of amine acid and 260 parts of xylene are then added, followed by heating under the action of a reflux condenser for an additional 7 hours. By the end of this period, only 8 hours of water had accumulated. The mixture is cooled and filtered to remove 17.4 parts of the material, insoluble in xylene. Then xylene is distilled off from the filtrate at a residual pressure of 30-40 mm Hg. Art. and the residue is distilled at a residual pressure of 3-4 mm wg. Art. at a temperature of 80-82 ° C. 31 parts of several contaminated N-butylmaleimide are obtained. The content of impurities is determined by infrared analysis. Analyzes on the content of maleipic anhydride and nitrogen show its presence in the mixture in the amount of 18 mol. %

Similar results can be obtained using N-ethyl, Nn-propyl, Nn-hexyl, N-cyclohexyl, Nn-dodecyl and N-4-chlorobutyl maleamipic acid.

Example 22. 100 parts of N-allyl maleamic acid and 430 parts of dry xylene are mixed and heated under the action of a reflux condenser in a Dean-Stark apparatus for 5 hours together with 4 hours of n-toluenesulfonic acid. 9.6 parts of water has accumulated. Then xylene is distilled off under reduced pressure, and the residue is distilled under high vacuum. Receive 29.5 parts of N-allylmaleimide, so pl. 45 ° C.

Example 23. A series of experiments were carried out to prepare N-o-chlorophenyl maleimide by conducting a one-step process using maleic anhydride and an amine as starting materials. 196 parts of maleic anhydride are dissolved in approximately 1700 parts of diluent in the flask. To this solution, a solution of 255 parts of o-chloroapylin is slowly added in approximately 200 parts of the diluent. Almost immediately, amipic acid begins to precipitate. The mixture is stirred moderately at room temperature for about 22 hours.

: In examples 23 and 24, by the end of this period, the suspension of amine acid is treated with 16 parts of the catalyst selected for the cyclization reaction, and the resulting suspension is then slowly added to the solution heated in a Dean-Stark apparatus under the action of a reverse chlodilic and containing an additional 16 hours catalyst in a solvent selected for the amine acid production process. In Examples 25 to 31, the entire catalyst is added to the suspension of amine acid, and the entire amount of the mixture is heated under the action of a reverse cooler in a Dean-Stark apparatus.

can be judged by the amount of water formed) The reaction mixture is cooled, filtered to eliminate by-products and mixed with sodium bicarbonate solution to completely remove acid residues. The mixture is then re-filtered, the solvent is evaporated in vacuo and the residue is distilled in vacuo to give pure nmide. The conditions and results of each synthesis are given in table. 2

table 2

15

20

25

Note e: Only 16 g of catalyst is used. The diluent is xylene, and in example 28 is toluene.

Example 32. The process described in Example 23 is repeated, with the difference that the catalyst and all of the amic acid are heated from the beginning of the cyclization reaction, and no further amic acid is added. The yield of o-chlorophenyl maleimide is only 61.9%. The product is characterized by a lower degree of purity, which can be judged by a more intense yellow color.

Example 33. The following series of experiments was carried out as indicated above. 196 parts of maleic anhydride are dissolved in a flask at approximately 1700 parts of diluent. A 225 part o-chloraniline solution is gradually added to this solution in approximately 200 parts of the diluent. The aminic acid begins to precipitate as a precipitate overnight. The mixture is gently stirred at compatte temperature for about 22 hours. In most of the examples, the amine acid suspension thus obtained is then treated with a certain amount of acid catalyst and heated under the action of a reflux condenser in the Dean-Stark Annarate.

In Example 44, the suspension of amine acid is gradually added to the mixture of diluent and catalyst heated by the action of a reflux cooler.

In examples 45 and 46, the mixture of suspension of amine acid and half a certain amount of catalyst is gradually added to the mixture of the remaining catalyst with a diluent heated by the action of a reflux condenser. The conditions and results of each experiment are given in table. 3

Table 3