Racemic praziquanamine recovery and preparation method
A technology of praziquantel and racemization, which is applied in the field of recovery and preparation of pharmaceutical intermediate-racemic praziquantel, can solve the problems of loss of key intermediates, rising costs, and inability to industrialize production, so as to reduce production costs and save production cost effect
Active Publication Date: 2017-09-12
SHANGHAI INST OF PHARMA IND CO LTD +1
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Problems solved by technology
[0006] At present, the scientific community has carried out in-depth research on the synthesis of L-praziquantel. The main problem is that the cost remains high and industrial production cannot be carried out.
[0028] For the preparation of L-praziquantel by the above resolution method, 50% of the key intermediate of the unwanted configuration praziquantel S-1 in the racemate will be lost, resulting in a substantial increase in cost
Method used
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Embodiment 1-12
[0078] Example 1-12, Synthesis of Compound 2
[0079]
Embodiment 1
[0081] Add 5.0g S-praziquantel (compound S-1), 0.25g palladium on carbon, 100ml toluene, and reflux for 45h under nitrogen protection in a 250ml reaction flask. Cool, filter, and evaporate the solvent under reduced pressure. Chromatography (eluent: ethyl acetate / petroleum ether) was separated, and the eluent was concentrated to obtain the target product, 2.0 g of light green solid, with a yield of 40.8%. 1 HNMR(CDCl 3 )δ:3.03(t,2H),4.23(t,2H),7.26~7.80(m,4H),7.86(s,1H),8.12(s,1H); MS(ESI)m / z:199.1( [M+1] + ),221.1([M+Na] + ),237.1([M+K] + )
Embodiment 2
[0083] Add 5.0g S-praziquantel (compound S-1), 0.25g palladium on carbon, 100ml xylene, and react at 140°C for 40h under nitrogen protection in a 250ml reaction flask. Cool, filter, and evaporate the solvent under reduced pressure. After separation by column chromatography (eluent: ethyl acetate / petroleum ether), the eluent was concentrated to obtain the target product, which was 1.6 g of light green solid, with a yield of 32.6%.
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Abstract
The present invention discloses a racemic praziquanamine-1 recovery and preparation method, which comprises: 1) preparing a compound 2 by using a waste material S-praziquanamine intermediate-1 as a starting raw material under the action of a catalyst or a dehydrogenation reagent; and 2) carrying out hydrogenation reduction on the compound 2 to obtain the racemic praziquanamine-1, wherein the formulas S-1, 1 and 2 are defined in the specification, the operations of the step 1) specifically comprise dissolving S-praziquanamine-1 in a first solvent, adding a first catalyst or a dehydrogenation reagent, and carrying out a reaction at a proper temperature to obtain the compound 2, and the operations of the step 2) specifically comprise dissolving the compound 2 in a second solvent, adding a second catalyst or a dehydrogenation reagent, and carrying out a reaction at a proper temperature to obtain the racemic praziquanamine-1. According to the present invention, the unwanted configuration praziquanamine S-1 is completely recovered and utilized to obtain the racemic compound 1, and the L-praziquantel is prepared by using the racemic compound 1 through the resolution method, such that the waste can be turned into treasure, and the L-praziquantel production cost can be substantially saved.
Description
Technical field [0001] The invention belongs to the field of drug synthesis, and specifically relates to a method for recovering and preparing racemic praziquantel, a pharmaceutical intermediate of anti-insect drug-L-praziquantel. Background technique [0002] Praziquantel (Praziquantel) is a broad-spectrum antiparasitic drug that is suitable for schistosomiasis japonicum, schistosomiasis heptasis, schistosomiasis mansoni, paragonimiasis (paragonimiasis), clonorchiasis, and The treatment of worm disease, cysticercosis, montmorillonite sparganosis, ginger worm disease, worm disease, etc. is especially suitable for the treatment of schistosomiasis japonica and clonorchiasis. After it was first marketed in Germany under the trade name "Cesol" in 1980, it soon became the drug of choice for the treatment of helminthiasis. [0003] [0004] The dose of racemic praziquantel is large and the adverse reactions are obvious. It has been reported in the literature that L-praziquantel (R-3) i...
Claims
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IPC IPC(8): C07D471/04
Inventor 张福利杨哲洲
Owner SHANGHAI INST OF PHARMA IND CO LTD