61196-37-0Relevant academic research and scientific papers
A preparation method of praziquantel (by machine translation)
-
Paragraph 0028; 0034; 0035, (2019/02/27)
The invention discloses a method for preparation of praziquantel, comprises the following steps: S1, β - phenethylamine with chloroacetyl chloride in a polar aprotic solvent, under alkaline compound to promote the acylation reaction is carried out, to produce intermediate I: 2 - chloro - N - (2 - phenyl-ethyl) - acetamide; S2, intermediate I in ethanolamine in the condensation reaction, an intermediate II: 2 - (2 - hydroxy - ethylamino) - N - phenethyl - acetamide; S3, using the intermediate II and TEMPO as raw materials, after oxidation is carried out after the cyclization reaction to prepare the intermediate III: 4 - carbon yl - 1, 2, 3, 6, 7, 11b - hexahydro - 4 H - pyrazinyl [2, 1 - a] isoquinoline; S4, the intermediate III with the cyclohexyl chloride in a polar aprotic solvent, a basic compound for promoting the next, react to generate the target product pqt. The preparation method has the raw materials are easy, the price is cheap; the process is simple, the production safety; high yield, low cost and the like. (by machine translation)
Recovery preparation method of racepiquamine
-
Paragraph 0080; 0081; 0082; 0085; 0087; 0089; 0091; 0093, (2018/06/12)
The invention discloses a recovery preparation method of racepiquamine-1. The preparation method comprises the following steps: dissolving a waste material S-piquamine intermediate-1 as an initial rawmaterial in a solvent; and carrying out reaction at a proper temperature in the presence of a catalyst and hydrogen at a certain pressure to prepare the piquamine intermediate-1 of racemate. The formula is as shown in the description. The configured piquamine S-1 which is not needed is efficiently, conveniently and fully operated and recovered with a high yield to obtain a racemate compound 1, and then the racemate compound is used again to prepare levopraziquantel, so that wastes can be turned into wealth, and therefore, the generation cost of the levopraziquantel is saved greatly.
Br?nsted acid-mediated cyclization-dehydrosulfonylation/reduction sequences: An easy access to pyrazinoisoquinolines and pyridopyrazines
Rao, Ramana Sreenivasa,Ramanathan, Chinnasamy Ramaraj
, p. 428 - 440 (2017/03/14)
An efficient and alternative synthetic approach has been developed to prepare various N-(arylethyl)piperazine-2,6-diones from 4-benzenesulfonyliminodiacetic acid and primary amines using carbonyldiimidazole in the presence of a catalytic amount of DMAP at ambient temperature. Piperazine-2,6-diones are successfully transformed to pharmaceutically useful pyridopyrazines or pyrazinoisoquinolines and ene-diamides via an imide carbonyl group activation strategy using a Br?nsted acid. Subsequent dehydrosulfonylation reactions of the ene-diamides, in a one pot manner, smoothly transformed them to substituted pyrazinones. A concise synthesis of praziquantel (1) has also been achieved through this method.
Racemic praziquanamine recovery and preparation method
-
Paragraph 0114; 0115; 0116; 0117; 0118; 0119; 0120-0141, (2017/09/19)
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.
One-pot palladium-catalyzed racemization of (S)-praziquanamine: A key intermediate for the anthelmintic agent (R)-praziquantel
Yang, Zhezhou,Guo, Xiang,Xu, Shanghu,Jiao, Huirong,Tan, Zhinmin,Zhang, Fuli
, p. 122 - 130 (2017/03/01)
An one-pot palladium-catalyzed procedure for racemization of (S)-praziquanamine, which is the undesired enantiomer and produced during the resolution step for preparing the anthelmintic drug (R)-praziquantel, has been developed through dehydrogenation of
Praziquantel synthetic technology
-
, (2016/11/28)
The invention discloses a praziquantel synthetic technology; beta-phenylethylamine, amino acetyl halide hydrochloride, halogenated acetaldehyde alcohol and cyclohexyl formyl chloride are used as raw materials and subjected to condensation, cyclization and acylation to synthesize praziquantel. The method has the advantages of cheap and easily available raw materials, low toxicity, safe production and simple process; amino acetyl halide hydrochloride and beta-phenylethylamine are condensed, the activity is moderate and the yield is relatively high; with reaction of halogenated aldehyde alcohol and an intermediate A, because halogen of halogenated aldehyde alcohol is easy to remove, the reaction is easy to implement, and the yield is favorable to improve; secondly, the synthetic technology has the advantages of mild synthetic reaction conditions, atmospheric pressure operation, safe operation and concise synthetic steps, and the total yield can be more than 50%; and the synthetic process has less waste emissions, pollution is low, the technology is a clean and highly efficient synthetic technology, and the production cost can be reduced by about 30%.
A method for synthesizing metabolite pqt (by machine translation)
-
Paragraph 0029; 0030, (2017/01/02)
The invention relates to two kinds of pqt of the synthetic method of metabolic product, belongs to the technical field of medicament, are respectively to pqt and 4 the hydroxy [...] cyclohexane carboxylic acid methyl ester as the raw material, pqt and cyclohexenols -3 the [...] formic acid as the raw material to synthesize the pqt two metabolic product. The advantages of: the invention the first time the two portions metabolic product. And, these two kinds of pqt metabolic product of simple synthesis technology, high purity of the product. (by machine translation)
METHOD FOR THE PRODUCTION OF PRAZIQUANTEL AND PRECURSORS THEREOF
-
Page/Page column 28-29, (2016/06/15)
The present invention relates to methods for the production of enantiopure or enantioenriched Praziquantel precursors and to methods for the production of enantiopure or enantioenriched Praziquantel comprising the methods for the production of the Praziquantel precursors. The present invention further relates to compounds or intermediates useful in such methods.
Development of chiral praziquantel analogues as potential drug candidates with activity to juvenile Schistosoma japonicum
Zheng, Yang,Dong, Lanlan,Hu, Changyan,Zhao, Bo,Yang, Chunhua,Xia, Chaoming,Sun, Dequn
supporting information, p. 4223 - 4226 (2014/11/07)
A series of chiral praziquantel analogues were synthesized and evaluated against Schistosoma japonicum both in vitro and in vivo. All compounds exhibited low to considerable good activity in vivo. Remarkably, worm reduction rate of R-3 was 60.0% at a sing
