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Method for synthesizing DL-alpha-amino caprolactam

An aminocaprolactam, caprolactam technology, applied in the direction of organic chemistry and the like, can solve the problems of complicated purification, complicated operation, many reaction steps, etc., and achieves the effects of safe operation, easy availability of raw materials, and easy separation.

Active Publication Date: 2011-06-15
NANJING UNIV OF TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The above several methods mainly have the following disadvantages: 1, in the reaction process, isomer piperidine-2-carboxamide is generated, and the product is inconveniently separated
2. The yield is low and the purification is more complicated
3. Although the yield of this route is relatively high, flammable and explosive azides are used as raw materials in the route, which is not suitable for industrialized production
4. There are many reaction steps and the operation is complicated

Method used

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  • Method for synthesizing DL-alpha-amino caprolactam
  • Method for synthesizing DL-alpha-amino caprolactam
  • Method for synthesizing DL-alpha-amino caprolactam

Examples

Experimental program
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Effect test

Embodiment 1

[0022] α-Chlorocaprolactam (14.8g, 0.1mol) and benzylamine (11.8g, 0.11mol), K 2 CO 3 (13.7g, 0.1mol), N,N-dimethylformamide (50mL) were added to the reactor together, the temperature was raised to 145°C, and after constant temperature reaction for 4h, it was poured into 200ml of water, and the solid was precipitated by stirring, filtered, washed with water, After drying, 18.1 g of N-benzyl-DL-α-aminocaprolactam was obtained, with a yield of 81.04%. The obtained N-benzyl-DL-α-aminocaprolactam proton nuclear magnetic resonance spectrum is as follows figure 1 shown. Add 18.1g of N-benzyl-DL-α-aminocaprolactam into the reactor, add 1g of 10% Pd-C and 3.82g of formic acid, reflux in 50ml of methanol for 4h, stop the reaction, filter, spin dry the solvent, ethyl acetate The ester was recrystallized to obtain 7.1 g of the target product DL-α-aminocaprolactam, with a yield of 66.81%. The obtained DL-α-aminocaprolactam nuclear magnetic resonance spectrum is as follows figure 2 s...

Embodiment 2

[0024] α-Chlorocaprolactam (14.8g, 0.1mol) and benzylamine (16.1g, 0.15mol), K 2 CO 3 (13.7g, 0.1mol), N,N-dimethylformamide (50mL) were added to the reactor together, the temperature was raised to 145°C, and the constant temperature reaction was carried out for 4h, poured into 200ml of water, stirred to precipitate a solid, filtered, washed with water, and dried 18.5 g of N-benzyl-DL-α-aminocaprolactam was obtained, with a yield of 84.75%. Add 18.5g of N-benzyl-DL-α-aminocaprolactam into the reactor, add 2g of 5% Pd-C and 5g of formic acid, reflux in 50ml of methanol for 3.5h, stop the reaction, filter, spin dry the solvent, ethyl acetate The ester was recrystallized to obtain 7.3 g of the target product DL-α-aminocaprolactam, with a yield of 67.2%. [Mp: 68.2-71℃; FAB-MS m / z: 129.1[M+1] + ]

Embodiment 3

[0026] α-Chlorocaprolactam (44.3g, 0.3mol) and benzylamine (112.5g, 1.05mol), K 2 CO 3 (27.4g, 0.2mol), 1,2-propanediol (150mL) were added to the reactor together, the temperature was raised to 100°C, the temperature was reacted for 3h, cooled to room temperature, added to 500ml of water, stirred to precipitate a solid, filtered, washed with water, and dried 50.6 g of N-benzyl-DL-α-aminocaprolactam was obtained, with a yield of 77.23%. Add 50.6 g of the obtained N-benzyl-DL-α-aminocaprolactam into the reactor, add 5 g of 10% Pd-C and 10.7 g of formic acid, reflux in 150 ml of ethanol for 3 hours, stop the reaction, filter, spin dry the solvent, acetic acid Ethyl ester was recrystallized to obtain 19.5 g of the target product DL-α-aminocaprolactam, with a yield of 65.63%. [Mp: 68.2-70.6℃; FAB-MS m / z: 129.1[M+1] + ]

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Abstract

The invention discloses a method for synthesizing DL-alpha-amino caprolactam. The method for synthesizing the DL-alpha-amino caprolactam comprises the following two steps of: 1, performing nucleophilic substitution reaction on alpha-halogenated caprolactam and benzyl amine under a certain condition; and 2, performing hydrogenolysis to remove benzyl and generate the required DL-alpha-amino caprolactam. In the method for synthesizing the DL-alpha-amino caprolactam, virulent, flammable and combustible NaN3 is avoided; the whole process is safe, simple and convenient in operation; an intermediate and a product are convenient to separate; the yield is high; and the method is suitable for industrialized large-scale production.

Description

Technical field: [0001] The invention relates to a synthesis method of DL-α-aminocaprolactam, which is suitable for the preparation of DL-α-aminocaprolactam. Background technique: [0002] DL-α-aminocaprolactam can be used as a precursor for the production of lysine. The synthesis of DL-α-aminocaprolactam has been reported in the literature. [0003] The synthesis methods reported in the literature mainly include: 1. Preparation of DL-α-aminocaprolactam by reacting α-halogenated caprolactam with liquid ammonia (US 2876218). 2. The method of synthesizing DL-α-aminocaprolactam by Gabriel synthesis method: 1) N-phthaloyl-DL-α- Aminocaprolactam; 2) hydrazinolysis and de-phthalyl to obtain DL-α-aminocaprolactam. (US3331835). 3. A synthetic method for preparing DL-α-aminocaprolactam by reacting α-halogenated caprolactam with sodium azide as a raw material. (Helv. Chim. Acta, 1958, 41(8): 181-8.). 4. Using cyclohexene as raw material, it can be obtained through addition, ammo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D223/10
Inventor 王德才刘华权范东梅唐伟韦萍欧阳平凯
Owner NANJING UNIV OF TECH
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