cas 104632-25-9, Pramipexole dihydrochloride

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Preparation method of pramipexole
The invention discloses a preparation method of pramipexole. The method comprises the following steps: adding (S)-2-amino-6-propionylamino-4,5,6,7-tetrahydrobenzothiazole into tetrahydrofuran, and carrying out a reduction reaction by using a sodium borohydride/boron trifluoride complex, wherein a molar ratio of (S)-2-amino-6-propionylamino-4,5,6,7-tetrahydrobenzothiazole to sodium borohydride to boron trifluoride complex is 1:1:2-1:3:4; and separating to obtain a target product (S)-2-amino-6-propylamino-4,5,6,7-tetrahydrobenzothiazole. The method provided by the invention has the advantages that the required raw materials are simple and easily available, the reaction conditions are mild, the use amount of the sodium borohydride/boron trifluoride complex is greatly reduced compared with theprior art, the reaction safety is greatly improved while the cost is saved, and the yield and the purity are higher, so that the method is suitable for industrial production.
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Paragraph 0033-0034

(2020/04/17)

Preparation method of pramipexole dihydrochloride
The invention relates to a preparation method of pramipexole dihydrochloride in the technical field of medicine preparation. The method includes adding (S)-2,6-diamino-4, 6-diamino-4,5,6,7-tetrahydrobenzothiazole adopted as an initial raw material I together with n-propyl p-toluenesulfonate into a toluene solvent; carrying out N-alkylation by the n-propyl p-toluenesulfonate under the action of analkali and a phase transfer catalyst to generate (S)-2-amino-6-propionamido-4,5,6,7-tetrahydrobenzothiazole (II); and dropwise adding hydrochloric acid for salifying the compound II in toluene to obtain the pramipexole dihydrochloride. According to the method, the n-propyl p-toluenesulfonate is selected as an alkylation reagent, an alkylation reaction of amino is completed in one step to obtain pramipexole, the hydrochloric acid is directly dropwise added into the pramipexole to form the salt without separation, the reaction steps are shortened, and the economic benefits of the product are improved.
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Paragraph 0017-0025

(2020/05/09)

Industrial preparation method for pramipexole and hydrochloride thereof
The invention relates to a preparation method for S-(-)pramipexole. The method comprises the following steps: (1) dissolving S-(-)-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole in a mixed solvent, carrying out stirring, adding a basic catalyst and n-propyl p-toluenesulfonate, carrying out heating after completion of addition, then carrying out a stirring reaction, and carrying out filtering and drying after completion of the reaction so as to obtain white S-(-)pramipexole p-toluenesulfonate solid; and (2) adding S-(-)pramipexole p-toluenesulfonate into an aqueous solution of salt, adding an inorganic base under stirring, carrying out stirring at room temperature after completion of addition, and carrying out filtering and drying so as to obtain a white S-(-)pramipexole solid, wherein no organic solvent is used in the step (2).
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Paragraph 0088-0089; 0092-0093

(2018/04/01)

Convenient N-Alkylation of amines using an effective magnetically separable supported ionic liquid containing an anionic polyoxometalate
Abstract: An effective synthesis of anion-exchanged supported ionic liquid using magnetically separable nanoparticles and its catalytic effect on N-alkylation reactions is described. Anionic polyoxometalate derivative was used in the anion-exchange step in catalyst design. The catalytic system can be easily separated from the reaction mixture with external magnetic field and recycled in subsequent reactions. In order to evaluate catalyst repeatability, N-alkylation of some more amines such as Aniline, 4-aminobenzenesulfonamide, 4-methoxyaniline, 2-aminopyrimidin and 4,5,6,7-tetrahydrobenzo[d]thiazole-2,6-diamine in the presence of recoverable catalyst was successfully examined in this article. In addition, pramipexole dihydrochloride as an active pharmaceutical ingredient was successfully synthesized using the catalytic system. The structure of catalyst was determined by infrared spectroscopy, X-ray powder diffraction, and scanning electron microscope techniques. The structure of organic products was determined by 1H NMR, 13C NMR, infrared and Mass spectroscopy. Graphical Abstract: [Figure not available: see fulltext.]
Ghasemi, Mohammad Hadi,Kowsari, Elaheh
p. 1957 - 1968
(2017/02/15)

A preparation method of pramipexole hydrochloride (by machine translation)
The invention discloses a method for preparation of pramipexole hydrochloride, comprises the following steps: 1) in the organic solvent, in order to 2, 6 - diamino - 4, 5, 6, 7 - tetrahydrobenzo and thiazole as the raw material, to join the resolving agent, heating to reflux, cooling, filtering, basified, make the (-) - (6 s) - 2, 6 - diamino 4, 5, 6, 7 - tetrahydrobenzo and thiazole; 2) in ethanol solution, the (-) - (6 s) - 2, 6 - diamino 4, 5, 6, 7 - tetrahydrobenzo and thiazole, and c anhydride reaction, by heating to reflux, to obtain (-) - (6 s) - 2 - amino - 6 - propionyl amino - 4, 5, 6, 7 - tetrahydrobenzo and thiazole; 3) (-) - (6 s) - 2 - amino - 6 - propionyl amino - 4, 5, 6, 7 - tetrahydrobenzo and thiazole in toluene solution in red aluminum reduction reaction, by heating to reflux, stirring, after devitrifying, make the use of pramipexole; the pramipexole into the isopropyl alcohol solution, by stirring, after devitrifying, react with hydrochloric acid, by decompression, drying, hydrochloride pramipexole. The preparation method is reaction low requirements on the equipment, the pramipexole prepared hydrochloric acid content is high, high purity, high solubility, the output is high, there is little impurity. (by machine translation)
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Paragraph 0057; 0063; 0064; 0065; 0066

(2017/12/27)

Synthesis method of pramipexole hydrochloride intermediate
The invention discloses a synthesis method of a pramipexole hydrochloride intermediate, wherein the method comprises the following steps: under the protection of inert gas, adding potassium borohydride and Lewis acid into a solvent to form a reduction system; and adding (S)-2-amino-6-aminopropyl-4,5,6,7-tetrahydrobenzothiazole into the reduction system, and carrying out a reaction to obtain the pramipexole hydrochloride intermediate. In the synthesis method of the pramipexole hydrochloride intermediate, use of flammable and explosive reducing agents such as lithium aluminum hydride and red aluminum and use of poisonous reducing agents such as borane are avoided, and thus the reaction is safe.
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Paragraph 0057; 0058; 0059; 0060; 0061; 0062

(2017/01/17)

PROCESS FOR THE PREPARATION OF PRAMIPEXOLE
The present invention refers to of Parkinson's disease treating agent containing a pramipexole economically and efficiently producing and method relates to novel intermediates.
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Paragraph 0075; 0076

(2016/11/28)

AN IMPROVED PROCESS FOR THE PREPARATION OF PRAMIPEXOLE DIHYDROCHLORIDE MONOHYDRATE
The present invention relates to an improved process for the preparation of the dihydrochloride monohydrate salt of (S)-2-amino-4,5,6,7-tetrahydro-6- (propylamino)benzothiazole (the compound of formula I) comprising reacting the compound of formula II with n-propanal and sodium borohydride using a mixture of methanol and dichloromethane (DCM) as the solvent to obtain the compound of formula I; followed by converting the compound of formula I into its monohydrochloride salt; purifying the monohydrochloride salt of the compound of formula I; and finally converting the pure monohydrochloride salt of the compound of formula I into the dihydrochloride monohydrate salt.
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Page/Page column 16-17

(2015/11/03)

Baker's yeast catalyzed preparation of a new enantiomerically pure synthon of (S)-pramipexole and its enantiomer (dexpramipexole) This work is dedicated to Professor Enzo Santaniello in the year of his 70th birthday
A biocatalyzed reduction of a prochiral bicyclic ketone afforded enantiomerically pure (R)-2-acetylamino-6-hydroxy-4,5,6,7-tetrahydrobenzothiazole, a synthon of the anti-Parkinson (S)-pramipexole and its (R)-isomer, which is currently under investigation for the treatment of amyotrophic lateral sclerosis (ALS).
Ferraboschi, Patrizia,Ciceri, Samuele,Ciuffreda, Pierangela,De Mieri, Maria,Romano, Diego,Grisenti, Paride
p. 1239 - 1245
(2015/02/19)

Amide activation by TMSCl: Reduction of amides to amines by LiAlH 4 under mild conditions
An expeditious and practical method for the reduction of amides to amines is reported. The method consists of activation of amides with TMSCl followed by reduction with LiAlH4. Various amides/lactams including hindered amides and secondary amides gave the corresponding amines in good to excellent yields. This novel protocol has a wide substrate scope and shows good functional group tolerance with high stereoretention.
Ravinder,Rajeswar Reddy,Panasa Reddy,Bandichhor, Rakeshwar
supporting information
p. 4908 - 4913
(2013/08/28)

IMPROVED PROCESS FOR THE PREPARATION OF (S)-2-AMINO-4,5,6,7-TETRAHYDRO-6 - (PROPYLAMINO) BENZOTHIAZOLE AND ITS PHARMACEUTICALLY ACCEPTABLE SALTS
The present invention relates to an improved process for the preparation of of (S)-2-amino-4,5,6,7-tetrahydro-6-(propylamino)benzothiazole and its pharmaceutically acceptable salts. Specifically relates to the compound represented by the following structural formula- Ia.
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Page/Page column 10; 15; 16

(2011/04/13)

PROCESS FOR THE PREPARATION OF PRAMIPEXOLE AND NEW ANHYDROUS FORMS OF ITS DIHYDROCHLORIDE
The present invention provides processes for the preparation of (?) pramipexole or an acid addition salt thereof of Formula I. The present invention further provides for the novel polymorphic Forms A and B of anhydrous pramipexole dihydrochloride.
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Page/Page column 4

(2009/04/24)

Process for producing pramipexole
The present invention relates to a process for preparing (S)-pramipexole and to certain intermediates useful therein.
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Page/Page column 11

(2008/06/13)

NOVEL PROCESS FOR SYNTHESIS OF PRAMIPEXOLE AND ITS PHARMACEUTICALLY ACCEPTABLE SALTS
The present invention relates to a novel process for synthesis of pramipexole, shown in the synthesis scheme. Formulae (I), (II), (III), (IV), (V) and (VI).
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Page/Page column 14-15; 17

(2008/12/08)

METHOD FOR THE RESOLUTION OF 2-AMINO-6-PROPYLAMINO-4,5,6,7-TETRAHYDROBENZOTHIAZOL AND INTERMEDIATE COMPOUNDS
The invention relates to a novel method for the resolution of the racemic mixture of compound (R,S)-2-amino-6-propylamino-4,5,6,7-tetrahydrobenzothiazole, or the enrichment of same with in one of its enantiomers, and to intermediate compounds which can be used to perform said method.
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Page/Page column 10

(2008/06/13)

PROCESS FOR PREPARING (S)-PRAMIPEXOLE AND ITS INTERMEDIATES
The present invention relates to an improved process for the preparation of (S)- 2,6-diamino-4,5,6,7-tetrahydrobenzothiazole of formula (II) useful in the preparation of pramipexole or (S)-2,6-amino-6-(n-propylamino)-4,5,6,7-tetrahydrobenzothiazole of formula (I) and its pharmaceutically acceptable salts or solvates thereof. The present invention further provides a process for the preparation of Pramipexole and its pharmaceutically acceptable salts, hydrates, solvates thereof.
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Page/Page column 18-19

(2008/06/13)

PROCESS FOR THE PREPARATION OF PRAMIPEXOLE BASE AND/OR ITS SALTS
The process for the preparation of pramipexole base and/or its pharmaceutically accepted salts, especially hydrochloride salt, is based on the reaction of (S)-(-)2,6-diamino-4,5,6,7-tetrahydrobenzothiazole with an alkylating agent, wherein the reaction is carried out with the absence of a base, in a solvent from which the resulting N-monoalkylated product selectively precipitates out as a salt, which, after isolation from the reaction mixture: a) upon the treatment of inorganic base is converted into free pramipexole base, and then into another pharmaceutically accepted pramipexole salt, or b) is converted directly into another pharmaceutically accepted pramipexole salt or the hydrate thereof.
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Page/Page column 7

(2008/06/13)

Process for the reduction of (S)-2-amino-6-propionamido-4,5,6,7-tetrahydrobenzo-thiazole
A process is disclosed for the reduction of (S)-2-amino-6-propionamido-4,5,6,7-tetrahydrobenzothiazole, which comprises reacting (S)-2-amino-6-propionamido-4,5,6,7-tetrahydrobenzothiazole with a borane reagent in the presence of suitable organic solvent to yield (S)-2-amino-6-propylamino-4,5,6,7-tetrahydrobenzothiazole base, which may be converted to an acid addition salt thereof. The process provided herein can be easily, conveniently and inexpensively scaled-up.
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Page/Page column 4

(2008/06/13)

Novel process for preparing pramipexole and its optical isomeric mixture by reduction with sodium triacetoxyborohydride
A novel process is provided for producing pramipexole base or its optical isomeric mixture as defined hereinabove i.e. (R,S)-2-amino-6-propyl-4,5,6,7-tetrahydrobenzothiazole avoiding the use of borane tetrahydrofuran complex and using a more convenient reducing agent like sodium triacetoxyborohydride instead. The provided process comprises reacting the starting material (S)-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole or its optical isomeric mixture as defined hereinabove i.e. (R,S)-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole with propionaldehyde in an organic solvent to obtain the respective enamine, which is subsequently reduced in situ, optionally without isolation, to obtain pramipexole or its optical isomeric mixture as defined hereinabove i.e. (R,S)-2-amino-6-propyl-4,5,6,7-tetrahydrobenzothiazole, and the acid addition salts thereof. The present invention also provides a process for purifying pramipexole dihydrochloride or the dihydrochloride salt of its optical isomeric mixture as defined hereinabove i.e. (R,S)-2-amino-6-propyl-4,5,6,7-tetrahydrobenzothiazole dihydrochloride by re-crystallization from a suitable solvent.
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Page/Page column 5

(2008/06/13)

IMPROVED PROCESS FOR THE PREPARATION OF BIOLOGICALLY ACTIVE TETRAHYDROBENZTHIAZOLE DERIVATIVE
Improved process for the preparation of the intermediate compound of formula II for formation pramipezole of formula (I) as well as the biological active tetrahydrobenzothiazole compound of formula (I) and/or its pharmaceutically acceptable salts or solvates.
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Page/Page column 10; 19

(2008/06/13)

PROCESS FOR PREPARING CHIRALLY PURE 2-AMINO-6-(ALKYL)AMINO-4,5,6,7-TETRAHYDROBENZOTHIAZOLES BY LIQUID CHROMATOGRAPHIC RESOLUTION
Processes for obtaining single enantiomers of 2-amino-6-(alkyl)amino-4,5,6,7-tetrahydrobenzothiazoles by liquid chromatography are disclosed.
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Page/Page column 21-22

(2008/06/13)

PROCESS FOR RESOLUTION OF 2-AMINO-6-PROPYLAMINO-4,5,6,7-TETRAHYDROBENZOTHIAZOLE AND COMPOUNDS THEREFOR
A new process to obtain pramipexole and related products is described. The process involves the reaction of new compounds of formula (6), wherein R is hydrogen or acyl group, R3 and R4 are either the same and each of them represents an alkoxy group of 1-4 carbons or they together form a C2-C5 alkylenedioxy group or an oxo-group, with an alkylamine in the presence of a reducing agent or a hydrogen gas with hydrogenation catalyst. A process to obtain new compounds of formula (6) is also described.
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(2008/06/13)

Process for preparation of 2-amino-6 (alkyl) amino-4,5,6,7-tetrahydrobenzothiazoles
A new process to obtain pramipexole and related products is described. The process involves the reaction of new compounds of formula (6), wherein R is hydrogen or acyl group, R3 and R4 are either the same and each of them represents an alkoxy group of 1-4 carbons or they together form a C2-C5 alkylenedioxy group or an oxo-group, with an alkylamine in the presence of a reducing agent or a hydrogen gas with hydrogenation catalyst. A process to obtain new compounds of formula (6) is also described.
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(2008/06/13)

Process for resolution of 2-amino-6-propylamino-4,5,6,7-tetrahydrobenzthiazole and compounds therefor
A process for resolving or enriching (R,S) 2-amino-6-propylamino-4,5,6,7-tetrahydrobenzothiazole (pramipexole) into optical isomers uses a monovalent salt thereof, e.g. pramipexole monohydrochloride, as a substrate. The monovalent salt is treated with an optically active acid, e.g. with L(+)-tartaric acid, to yield a diastereomeric mixed salt. The mixed salt is subjected to fractional crystallization to yield an optically enriched mixed salt. The mixed salt can be treated with base to liberate the desired isomer of pramipexole.
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(2008/06/13)