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One-pot synthesis method of praziquantel intermediate

The technology of an intermediate and praziquantel, which is applied in the field of preparation of pharmaceutical intermediates, can solve the problems of long steps, low yield, unfavorable industrial production and the like, and achieves the effects of less risk, lower feed ratio and significant application value.

Pending Publication Date: 2021-04-13
厦门优孚利生物医药科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0011] This route is also the method adopted by industrial production at home and abroad. Although the method has mature technology and easy-to-obtain raw materials, it uses thionyl chloride and concentrated sulfuric acid. The amount of "three wastes" is relatively large, the steps are long, and the yield is low, which is not conducive to industrialization. Production

Method used

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  • One-pot synthesis method of praziquantel intermediate
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  • One-pot synthesis method of praziquantel intermediate

Examples

Experimental program
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Effect test

Embodiment 1

[0031] The method for preparing 4-(cyclohexylcarbonyl)-3,4-dihydro-1-(2-phenethyl)-2(1h)-pyrazinone comprises the following steps:

[0032] 1) Preparation of A3: Add the reactant N-phenylethylaminoacetaldehyde dimethyl acetal (A1) (R in the general formula of A1 is methyl, 104.5 g, 0.5 mol) into a glass reaction bottle (reaction vessel), Start stirring, then slowly add N-cyclohexylglycine (A2) (92.5g, 0.5mol), control the temperature at 80-90°C, stir for 20 minutes, and wait for the next step.

[0033] 2) Preparation of 4-(cyclohexylcarbonyl)-3,4-dihydro-1-(2-phenylethyl)-2(1h)-pyrazinone (A4): Move the above glass reaction bottle into the microwave reactor (The microwave reactor can be refitted with a household microwave oven), a glass condenser and a receiving bottle are installed on the glass reaction bottle (the condenser and the receiving bottle can be pre-set in the household microwave oven to refit the household microwave oven, the frequency is 2450MHz), The air in the...

Embodiment 2

[0035] The method for preparing 4-(cyclohexylcarbonyl)-3,4-dihydro-1-(2-phenethyl)-2(1h)-pyrazinone comprises the following steps:

[0036] 1) Preparation of A3: Add the reactant N-phenylethylaminoacetaldehyde diethyl acetal (A1) (R selected ethyl in the general formula of A1, 118.5g, 0.5mol) into the glass reaction bottle, start stirring, and then Slowly add N-cyclohexylglycine (A2) (92.5 g, 0.5 mol), control the temperature at 90-100°C, stir for 30 minutes, and wait for the next step.

[0037] 2) Preparation of 4-(cyclohexylcarbonyl)-3,4-dihydro-1-(2-phenylethyl)-2(1h)-pyrazinone (A4): Move the above glass reaction bottle into the microwave reactor (The microwave reactor can be refitted with a household microwave oven, and the frequency is 2450MHz), a glass condenser and a receiving bottle are installed on the glass reaction bottle (the condenser and the receiving bottle can be pre-set in the household microwave oven to refit the household microwave oven), Replace the air i...

Embodiment 3

[0039] The method for preparing 4-(cyclohexylcarbonyl)-3,4-dihydro-1-(2-phenethyl)-2(1h)-pyrazinone comprises the following steps:

[0040] 1) Preparation of A3: Add the reactant N-phenylethylaminoacetaldehyde diethyl acetal (A1) (R in the general formula of A1 is ethyl, 124.4g, 0.525mol) into the glass reaction bottle, start stirring and then slowly Add N-cyclohexylglycine (A2) (92.5 g, 0.5 mol), control the temperature at 100-120° C., stir for 40 minutes, and wait for the next step.

[0041]2) Preparation of 4-(cyclohexylcarbonyl)-3,4-dihydro-1-(2-phenylethyl)-2(1h)-pyrazinone (A4): Move the above glass reaction bottle into the microwave reactor (The microwave reactor can be refitted with a household microwave oven, and the frequency is 2450MHz), a glass condenser and a receiving bottle are installed on the glass reaction bottle (the condenser and the receiving bottle can be pre-set in the household microwave oven to refit the household microwave oven), Replace the air in t...

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Abstract

The invention discloses a one-pot synthesis method of a praziquantel intermediate. The method comprises the steps of adding N-phenylethyl aminoacetaldehyde dialkyl alcohol (A1) and N-cyclohexylformyl glycine (A2) into a reaction vessel, reacting to obtain a compound as shown in a general formula A3, adding a condensation receiving device on the reaction vessel, replacing air in the reaction container and the condensation receiving device with nitrogen, carrying out microwave reaction in a microwave reactor, and after the microwave reaction is finished, adding an organic solvent to crystallize to obtain white solid 4-(cyclohexylcarbonyl)-3, 4-dihydro-1-(2-phenethyl)-2-(1h)-pyrazinone (A4). By adopting the method, the high-purity praziquantel intermediate can be prepared, and the industrial production requirement of the praziquantel intermediate can be met.

Description

technical field [0001] The present invention relates to the preparation of pharmaceutical intermediates, specifically a praziquantel intermediate 4-(cyclohexylcarbonyl)-3,4-dihydro-1-(2-phenylethyl)-2(1h)-pyridine One-pot synthesis of azinones. Background technique [0002] 4-(cyclohexylcarbonyl)-3,4-dihydro-1-(2-phenylethyl)-2(1h)-pyrazinone, the molecular formula is C 19 h 24 N 2 o 2 , with a molecular weight of 312 and a CAS registration number of 94494-35-6, white solid, used as a pharmaceutical intermediate for the synthesis of the anthelmintic drug praziquantel. [0003] The structural formula of 4-(cyclohexylcarbonyl)-3,4-dihydro-1-(2-phenylethyl)-2(1h)-pyrazinone is as follows: [0004] [0005] Currently, there are two main synthetic routes for 4-(cyclohexylcarbonyl)-3,4-dihydro-1-(2-phenylethyl)-2(1h)-pyrazinone: [0006] Synthetic route 1: [0007] [0008] This route is the method that industrial production adopts at home and abroad at present, altho...

Claims

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Application Information

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IPC IPC(8): C07D241/08
CPCC07D241/08
Inventor 黄振辉林朝森林峰
Owner 厦门优孚利生物医药科技有限公司