Praziquantel preparation process

A production process and technology of praziquantel, which is applied in the field of preparation of synthetic praziquantel intermediates, can solve the problems of a large amount of halogen-containing organic solvents, complex process operation, and high energy consumption, and achieve improved yield and purity, and process operation Simple, waste reduction effect

Active Publication Date: 2013-04-24
SHAOXING MINSHENG PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The technical problems existing in the above synthesis process are: 1. The key intermediate (1,2,3,7,11β-hexahydro4-hydro-pyrazino[2,1-α]isoquinoline- 4-ketone) is unstable, which leads to high impurity content in the finished product of praziquantel; 2. The process operation is complex and requires a large amount of halogen-containing organic solvent; 3. The energy consumption is large, the production efficiency is low, and the cost is high

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Examples

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Embodiment 1

[0034] Embodiment 1: The preparation method of a kind of praziquantel of the present embodiment is carried out according to the following steps:

[0035] (1) Add 136 g of 85% phosphoric acid and 120 g of compound I in sequence to a 500 mL three-neck flask equipped with a reflux condenser, a thermometer, and a magnetic stirring device, and turn on mechanical stirring for about ten minutes. Turn on the condensate, turn off the mechanical stirring, and turn on the heating to 150°C. After 2 hours of heat preservation, turn on mechanical stirring and continue heat preservation for 5 hours;

[0036] (2), change reaction device into decompression device, open vacuum pump; Under heat preservation, decompression removes the benzoic acid that reaction generates, and pressure is at 5-20mbar, collects benzoic acid 40g. Slowly add 85 g of deionized water at 80°C to the reaction solution, reflux for 30 minutes, turn off the heating, cool down to room temperature, cool to 0°C and continue s...

Embodiment 2

[0048] Embodiment 2: the preparation method of a kind of praziquantel of the present embodiment, other steps are identical with embodiment 1, just the phosphoric acid consumption of step 1 and the deionized water consumption of step 2 are as follows:

[0049] In a 500mL three-neck flask equipped with a reflux condenser, a thermometer, and a magnetic stirring device, add 400g of 85% phosphoric acid and 120g of compound I in sequence, and start mechanical stirring for about ten minutes. Turn on the condensate, turn off the mechanical stirring, and turn on the heating to 150°C. After 2 hours of heat preservation, turn on mechanical stirring and continue heat preservation for 5 hours. After removing benzoic acid under reduced pressure, 200 g of deionized water at 80° C. was slowly added to the reaction liquid. 103 g of crude praziquantel was prepared, and 83 g of praziquantel was obtained by recrystallization.

Embodiment 3

[0050] Embodiment 3: the preparation method of a kind of praziquantel of the present embodiment, other steps are identical with embodiment 1, just the phosphoric acid consumption of step 1 and the deionized water consumption of step 2 are as follows:

[0051] In a 500mL three-neck flask equipped with a reflux condenser, a thermometer, and a magnetic stirring device, add 220g of 85% phosphoric acid and 120g of compound I in sequence, and start mechanical stirring for about ten minutes. Turn on the condensate, turn off the mechanical stirring, and turn on the heating to 150°C. After 2 hours of heat preservation, turn on mechanical stirring and continue heat preservation for 5 hours. After removing benzoic acid under reduced pressure, 200 g of deionized water at 80° C. was slowly added to the reaction liquid. 100 g of crude praziquantel was prepared, and 80 g of praziquantel was obtained by recrystallization.

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Abstract

The invention relates to a praziquantel preparation process which comprises the following steps of: carrying out hydrolysis reaction on 1, 2, 3, 6, 7, 11beta-hexahydro-4H-pyrazino[2,1-alpha]isoquinolin-4-one and phosphoric acid, carrying out reduced-pressure distillation on a reaction solution to remove generated byproducts, adding deionized water to dilute the reaction solution, and crystallizing to obtain a phosphate compound intermediate; carrying out cyclohexaformylation on the obtained phosphate compound intermediate and cyclohexaformyl chloride in an organic solvent in the presence of an alkali compound to obtain a praziquantel crude product; and decoloring and filtrating the obtained praziquantel crude product, and recrystallizing a filtrate to obtain a refined praziquantel. Compared with the prior art, the praziquantel preparation process has the advantages of shortening the process flow, reducing the use of the solvent and improving the quality and yield of the product.

Description

technical field [0001] The invention relates to a synthesis process of praziquantel, and further relates to the preparation of a synthetic praziquantel intermediate. Background technique [0002] Praziquantel (Praziquantel) is a broad-spectrum antiparasitic drug, which has a killing effect on lung flukes, schistosomiasis, clonorchis sinensis, hydatid, cysticercosis, Sparganum monzii, etc., and has small side effects and is not easy to treat. Drug resistance has become the drug of choice for the treatment of various parasitic diseases. [0003] German invention patent 2441261 and 2362539 disclose a kind of preparation method of praziquantel, mix reaction with isoquinoline, cyanide salt, basic compound, then carry out reduction reaction, cyclization reaction, finally through hydrolysis reaction, neutralization reaction and Amidation reaction gives crude praziquantel. The process is complicated to operate, needs to use a large amount of chloroform, has relatively high cost, a...

Claims

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Application Information

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IPC IPC(8): C07D471/04
CPCY02P20/582
Inventor 岳从永罗金表张涛
Owner SHAOXING MINSHENG PHARMA
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