84057-95-4

Capillary electrophoresis (CE) methods based on the conventional and complete filling techniques for determination of the enantiomeric purity of S-ropivacaine are described. The complete filling technique is a separation method which can be used instead of the partial filling technique in order to reduce the total analysis time, when the chiral selector solution does not absorb UV light. In the complete filling technique the total length of the capillary is filled with the chiral selector solution, prior to application of the analyte. During the run both ends of the capillary are connected to the background electrolyte, i.e. without chiral agent. An interlaboratory study was performed to validate the method. The limit of detection and quantification for R-ropivacaine were found to be about 0.6 and 1.6 μg/ml, respectively, corresponding to 0.1 and 0.25% enantiomeric purity of S-ropivacaine. Good performances were demonstrated for the repeatability and linearity. The consumption of the chiral selector was about 160 times lower with the complete filling technique compared with the conventional CE technique. Copyright (C) 1999 Elsevier Science B.V.

The preparation method comprises the following specific steps: 1) reacting (S)- piperidine -2 - formic acid with propionaldehyde in the presence of a reducing agent and an aprotic solvent to obtain the intermediate 1. 2). N. NIn the presence of -dimethylformamide and an aprotic solvent, the intermediate 1 obtained in step 1) and the acylating agent are subjected to an acylation reaction to give an intermediate 2. 3). N. N[-] The intermediate 2 obtained in step 2) and 2 and 6 -dimethylaniline are subjected to a condensation reaction in the presence of dimethylformamide and basic conditions to give an intermediate 3. 4) The intermediate 3 obtained in step 3) is salified with hydrochloric acid to give the ropivacaine hydrochloride crude product. 5) The ropivacaine hydrochloride is purified to obtain ropivacaine hydrochloride. The method has the advantages that the product purity is higher than 99.99%, the synthesis process is mild in reaction condition, simple in preparation process, low in cost, safe and environment-friendly, and is suitable for industrial production.

A novel and enantioselective synthesis of (S)-2-pipecolic acid (5) has been achieved from Oppolzer’s sultam (1) and ethyl N-(diphenylmethylene)glycinate (2) as readily available starting materials. The highly stereoselective alkylation of chiral glycine intermediate (3) with 1,4-dibromobutane afforded the key backbone of (S)-2-pipecolic acid (5) in one-step that was utilized into the preparation of the local anesthetics mepivacaine, ropivacaine and bupivacaine.

The invention discloses a preparation method of ropivacaine hydrochloride. The preparation method comprises steps as follows: (1) preparation of an intermediate (I), (2) preparation of an intermediate (II), (3) preparation of a crude product and (4) refin

The modulation of pharmacologically relevant properties of N-alkyl-piperidine-2-carboxamides was studied by selective introduction of 1–3 fluorine atoms into the n-propyl and n-butyl side chains of the local anesthetics ropivacaine and levobupivacaine. The basicity modulation by nearby fluorine substituents is essentially additive and exhibits an exponential attenuation as a function of topological distance between fluorine and the basic center. The intrinsic lipophilicity of the neutral piperidine derivatives displays the characteristic response noted for partially fluorinated alkyl groups attached to neutral heteroaryl systems. However, basicity decrease by nearby fluorine substituents affects lipophilicities at neutral pH, so that all partially fluorinated derivatives are of similar or higher lipophilicity than their non-fluorinated parents. Aqueous solubilities were found to correlate inversely with lipophilicity with a significant contribution from crystal packing energies, as indicated by variations in melting point temperatures. All fluorinated derivatives were found to be somewhat more readily oxidized in human liver microsomes, the rates of degradation correlating with increasing lipophilicity. Because the piperidine-2-carboxamide core is chiral, pairs with enantiomeric N-alkyl groups are diastereomeric. While little response to such stereoisomerism was observed for basicity or lipophilicity, more pronounced variations were observed for melting point temperatures and oxidative degradation.

The use of the "borrowing hydrogen strategy" in the synthesis of a number of typical pharmaceutical intermediates has been investigated. The main aim of this work was to investigate the scope and limitations of current methodology using standard laboratory techniques in an industrial context. Some interesting and significant results were achieved across a diverse set of complex substrates; however several drawbacks with this approach were identified, such as the high loading, poor turnover, and susceptibility to substrate inactivation of the catalysts. These are areas which are highlighted for future investigation and improvements.

Disclosed herein is a process for producing optically active 1-n-propyl-2',6'-dimethyl-2-piperidinecarboxanilide. The process comprises of reacting n-propyl pipecolate ester with 2,6-dimethylanilino magnesium halide. The 1-n-propyl-2',6'-dimethyl-2-piperi

The catalytic dynamic resolution (CDR) of rac-2-lithio-N-Boc-piperidine using chiral ligand 8 or its diastereomer 9 in the presence of TMEDA has led to the highly enantioselective syntheses of both enantiomers of 2-substituted piperidines using a wide range of electrophiles. The CDR has been applied to the synthesis of (R)- and (S)-pipecolic acid derivatives, (+)-β-conhydrine, (S)-(+)-pelletierine, and (S)-(-)-ropivacaine and the formal synthesis of ()-lasubine II and (+)-cermizine C.

Process for preparation of Ropivacaine hydrochloride monohydrate comprising resolution of racemic pipecoloxylidide in non-ketonic solvents to give (S)-pipecoloxylidide followed by N-propylation to in water ass reaction medium give (S)-Ropivacaine base; co

The present invention relates to an improved process for the preparation of high chiral purity (S)-1-alkyl-2',6'-Pipecoloxylidide compound such as Ropivacaine, Levobupivacaine or salts thereof, which comprises crystallization of (S)-1-alkyl-2',6'- Pipecoloxylidide acid addition salt in a non-alcoholic and non-ketonic solvent.

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An alternative asymmetric synthesis of ropivacaine and analogues employing the 'cation pool' strategy and host/guest supramolecular co-catalysis approach is presented. In this study, chiral auxiliaries, several soft nucleophiles as well as one-pot conditions for anodic oxidation, followed by nucleophilic addition, have been applied.

The invention pertains to a process for preparing stable anhydrous Ropivacaine hydrochloride, the process involving preparing Ropivacaine hydrochloride from Ropivacaine base, wherein Ropivacaine base is provided having a chiral purity of more than 95 %, a

A process for the preparation of an injectable solution of (2S)-(-)-N- (2;6-dimethyl-phenyl)-l-propyl-2-piperidincarboxamide (Ropivacaine) starting from Ropivacaine base substantially free from the dextro enantiomer, by dissolution of the same in water fo

The present invention describes a novel process of preparation of optically pure L-Pipecolic acid and an improved process for the conversion of L-pipecolic acid to L-N-(2,6-dimethylphenyl)-1-propyl-2-piperidinocarboxamide, its hydrochloride salt and hydrochloride monohydrate.