Method for preparing aminoacetaldehyde dimethyl acetal

Abstract

The invention relates to a method for preparing aminoacetaldehyde dimethyl acetal, which comprises the following steps: 1) adding dimethyl chloroacetal and an ammonia aqueous solution with a concentration of 10-40% into a container at a time, uniformly stirring; 2) stirring the reaction solution in step 1), heating the reaction solution to 100-150 DEG C; 3) performing distillation of the reaction solution in step 2), recovering the ammonia water till no obvious fraction is distilled out; 4) adding a sodium hydroxide aqueous solution with a concentration of 20%-50% into the reaction solution in step 3), adjusting the pH to 12-14; 5) performing rectification of the solution in step 4), and collecting colorless and light yellow transparent liquid which is the target product of aminoacetaldehyde dimethyl acetal.

Description

technical field

[0001] The technology of the invention relates to the technical field of medicine and chemical industry. Background technique

[0002] Aminoacetaldehyde dimethyl acetal (also known as: 2,2-dimethoxyethylamine), the molecular formula is: C 4 h 11 NO 2 It is a key intermediate for the synthesis of ivabradine hydrochloride, proline analogs and praziquantel and other raw materials. Therefore, it is of certain significance to synthesize aminoacetaldehyde dimethyl acetal with a low-cost, simple and safe production process. However, the existing process for producing aminoacetaldehyde dimethyl acetal uses vinyl acetate as a starting material, and synthesizes the target product through bromination, Gabriel synthesis, and hydrazinolysis. This process uses bromine, a highly toxic substance, and the process is complex and costly, and it is not easy to realize industrialization. Contents of the invention

[0003] Purpose of the invention: In order to overcome the ...

Examples

Embodiment 1

[0017] Add 400g of 10% aqueous ammonia solution into a 500ml autoclave, and then add 20g of chloroacetaldehyde dimethyl acetal at one time. Under stirring, the temperature of the reaction solution is raised to 135-140°C, and the temperature is controlled and stirred for 5 hours. Distill the reaction solution until no obvious fractions are distilled out, recover 220g of ammonia water, weigh 20g of 30% liquid caustic soda aqueous solution and add it to the remaining reaction solution, adjust the pH of the reaction solution to 14, rectify at atmospheric pressure, and collect a colorless transparent liquid 8.6g. The yield of aminoacetaldehyde dimethyl acetal in this embodiment is 47.4%.

Embodiment 2

[0019] Add 350g of 30% aqueous ammonia solution into a 500ml autoclave, and then add 30g of chloroacetaldehyde dimethyl acetal at one time. With stirring, the temperature of the reaction solution is raised to 145-150°C, and the temperature is controlled and stirred for 5 hours. Distill the reaction solution until no obvious fractions are distilled out, recover 190g of ammonia water, weigh 30g of 40% liquid caustic soda solution and add it to the remaining reaction solution, adjust the pH of the reaction solution to 14, rectify at atmospheric pressure, and collect a colorless transparent liquid 15g. The yield of aminoacetaldehyde dimethyl acetal in this example is 59.2%.

Embodiment 3

[0021] Add 350g of 40% aqueous ammonia solution into a 500ml autoclave, and then add 40g of chloroacetaldehyde dimethyl acetal at one time. With stirring, the temperature of the reaction solution is raised to 130-135°C, and the temperature is controlled and stirred for 3 hours. Distill the reaction solution until no obvious fractions are distilled out, recover 175g of ammonia water, weigh 40g of 50% liquid caustic soda aqueous solution and add it to the remaining reaction solution, adjust the pH of the reaction solution to 14, rectify at atmospheric pressure, and collect a colorless transparent liquid 24g. The yield of aminoacetaldehyde dimethyl acetal in this example is 71.1%.

technical field

[0001] The technology of the invention relates to the technical field of medicine and chemical industry. Background technique

[0002] Aminoacetaldehyde dimethyl acetal (also known as: 2,2-dimethoxyethylamine), the molecular formula is: C 4 h 11 NO 2 It is a key intermediate for the synthesis of ivabradine hydrochloride, proline analogs and praziquantel and other raw materials. Therefore, it is of certain significance to synthesize aminoacetaldehyde dimethyl acetal with a low-cost, simple and safe production process. However, the existing process for producing aminoacetaldehyde dimethyl acetal uses vinyl acetate as a starting material, and synthesizes the target product through bromination, Gabriel synthesis, and hydrazinolysis. This process uses bromine, a highly toxic substance, and the process is complex and costly, and it is not easy to realize industrialization. Contents of the invention

[0003] Purpose of the invention: In order to overcome the ...

Examples

Embodiment 1

[0017] Add 400g of 10% aqueous ammonia solution into a 500ml autoclave, and then add 20g of chloroacetaldehyde dimethyl acetal at one time. Under stirring, the temperature of the reaction solution is raised to 135-140°C, and the temperature is controlled and stirred for 5 hours. Distill the reaction solution until no obvious fractions are distilled out, recover 220g of ammonia water, weigh 20g of 30% liquid caustic soda aqueous solution and add it to the remaining reaction solution, adjust the pH of the reaction solution to 14, rectify at atmospheric pressure, and collect a colorless transparent liquid 8.6g. The yield of aminoacetaldehyde dimethyl acetal in this embodiment is 47.4%.

Embodiment 2

[0019] Add 350g of 30% aqueous ammonia solution into a 500ml autoclave, and then add 30g of chloroacetaldehyde dimethyl acetal at one time. With stirring, the temperature of the reaction solution is raised to 145-150°C, and the temperature is controlled and stirred for 5 hours. Distill the reaction solution until no obvious fractions are distilled out, recover 190g of ammonia water, weigh 30g of 40% liquid caustic soda solution and add it to the remaining reaction solution, adjust the pH of the reaction solution to 14, rectify at atmospheric pressure, and collect a colorless transparent liquid 15g. The yield of aminoacetaldehyde dimethyl acetal in this example is 59.2%.

Embodiment 3

[0021] Add 350g of 40% aqueous ammonia solution into a 500ml autoclave, and then add 40g of chloroacetaldehyde dimethyl acetal at one time. With stirring, the temperature of the reaction solution is raised to 130-135°C, and the temperature is controlled and stirred for 3 hours. Distill the reaction solution until no obvious fractions are distilled out, recover 175g of ammonia water, weigh 40g of 50% liquid caustic soda aqueous solution and add it to the remaining reaction solution, adjust the pH of the reaction solution to 14, rectify at atmospheric pressure, and collect a colorless transparent liquid 24g. The yield of aminoacetaldehyde dimethyl acetal in this example is 71.1%.