- Substituted α-mercaptoketones, new types of specific neprilysin inhibitors
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New neprilysin inhibitors containing an α-mercaptoketone HSC(R1R2)CO group, as zinc ligand were designed. Two parameters were explored for potency optimization: the size of the inhibitor which could interact with the S1, S
- Poras, Hervé,Patouret, Rémi,Leiris, Simon,Ouimet, Tanja,Fournié-Zaluski, Marie-Claude,Roques, Bernard P.
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p. 3883 - 3890
(2017/07/27)
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- Kinetic resolution of (R,S)-pyrazolides containing substituents in the leaving pyrazole for increased lipase enantioselectivity
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With hydrolysis of (R,S)-azolides in water-saturated methyl tert-butyl ether (MTBE) via Candida antarctica lipase B (CALB) as the model system, (R,S)-pyrazolides containing a leaving 3-, 4- or 3,4-substituted-pyrazole moiety are selected as the best substrates for preparing various optically pure carboxylic acids containing an α-chiral center. Great improvements of enzyme activity for the (R)-enantiomers with excellent enantioselectivity (VR/VS > 100) are obtainable, if (R,S)-pyrazolides containing a leaving 3- or 3,4-substituted-pyrazole moiety are employed for the hydrolysis or alcoholysis by methanol in anhydrous MTBE. A detailed kinetic analysis for (R,S)-N-2-phenylpropionylpyrazoles indicates that a bulky 3-substituent such as 3-(3-bromophenyl) or 3-(2-pyridyl) in the leaving pyrazole moiety has profound effects on decreasing the nucleophilic attack and proton transfer of catalytic serine for the slow-reacting enantiomer in anhydrous MTBE, as well as that and substrate affinity for both enantiomers in water-saturated MTBE. The resolution platform is also successfully applied to the hydrolysis of (R,S)-pyrazolides in water-saturated cyclohexane via Candida rugosa lipase (Lipase MY) having opposite enantioselectivity to CALB.
- Wang, Pei-Yun,Wu, Chia-Hui,Ciou, Jyun-Fen,Wu, An-Chi,Tsai, Shau-Wei
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experimental part
p. 113 - 119
(2011/02/21)
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- A variant of Yarrowia lipolytica lipase with improved activity and enantioselectivity for resolution of 2-bromo-arylacetic acid esters
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A variant of Lip2p lipase from Yarrowia lipolytica yeast was used for the resolution of 2-bromophenyl and o-tolyl acid esters, an important class of chemical intermediates for the pharmaceutical industry. In comparison with wild-type Lip2p, this variant, which contains one single amino acid change in the active site of the enzyme, V232A, displayed an enantioselectivity enhanced by one order of magnitude for the resolution of 2-bromo-phenylacetic acid ethyl ester (E-value increased from 5.5 to 59 for wild-type and V232A, respectively) and by fourfold for the resolution of 2-bromo-o-tolylacetic acid ethyl ester (going from an E-value of 27 to 111 for the wild-type and V232A, respectively). A remarkable increase in reaction velocity was also observed for both compounds, as a result of a significant gain in reactivity towards the favoured (S)-enantiomer (3- and 16-fold increase for 2-bromo-phenylacetic and -o-tolylacetic acid ethyl esters, respectively). These results demonstrate the key role of the V232 amino acid in enantiomer recognition and selectivity.
- Cancino, Miguel,Bauchart, Philippe,Sandoval, Georgina,Nicaud, Jean-Marc,Andre, Isabelle,Dossat, Valerie,Marty, Alain
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p. 1608 - 1612
(2008/12/21)
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- Synthesis, characterization, and application of chiral ionic liquids and their polymers in micellar electrokinetic chromatography
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Two amino acid-derived (leucinol and N-methylpyrrolidinol) chiral ionic liquids are synthesized and characterized in both monomeric and polymeric forms. Leucinol-based chiral cationic surfactant is a room-temperature ionic liquid, and pyrrolidinol-based chiral cationic surfactant melts at 30-35 °C to form an ionic liquid (IL). The monomeric and polymeric ILs are thoroughly characterized to determine critical micelle concentration, aggregation number, polarity, optical rotation, and partial specific volume. Herein, we present the first enantioseparation using chiral IL as a pseudostationary phase in capillary electrophoresis. Chiral separation of two acidic analytes, (±)-α- bromophenylacetic acid and (±)-2-(2-chlorophenoxy)propanoic acid (±)-(2-PPA) can be achieved with both monomers and polymers of undecenoxycarbonyl-L-pryrrolidinol bromide (L-UCPB) and undecenoxycarbonyl-L- leucinol bromide (L-UCLB) at 25 mM surfactant concentration using phosphate buffer at pH 7.50. The chiral recognition seems to be facilitated by the extent of interaction of the acidic analytes with the cationic head-group of chiral selectors. Polysodium N-undecenoxycarbonyl-L-leucine sulfate (poly-L-SUCLS) and polysodium N-undecenoxycarbonyl-L-leucinate (poly-L-SUCL) were compared at high and low pH for the enantioseparation of (±)-(2-PPA). AtpH 7.5, poly-L-SUCLS, poly-L-SUCL, and (±)-(2-PPA) are negatively charged resulting in no enantioseparation. However, chiral separation was observed for (±)-(2-PPA) using poly-L-SUCLS at low pH (pH 2.00) at which the analyte is neutral. The comparison of chiral separation of anionic and cationic surfactants demonstrates that the electrostatic interaction between the acidic analyte and cationic micelle plays a profound role in enantioseparation.
- Rizvi, Syed Asad Ali,Shamsi, Shahab A.
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p. 7061 - 7069
(2008/02/12)
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- PROCESSES FOR THE PRODUCTION OF OPTICALLY ACTIVE COMPOUNDS HAVING SUBSTITUENTS AT THE 2-POSITION
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The present invention provides a process for producing an optically active compound having a thio group at the 2-position important for manufacturing medicines. An optically active compound having a hydroxyl group at the 2-position is chlorinated with inv
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Page/Page column 14
(2010/02/14)
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- Lipase-catalyzed enantioselective transesterification toward esters of 2-bromo-tolylacetic acids
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Lipases from Candida antarctica, Pseudomonas cepacia and Rhizomucor miehei were tested in the resolution of seven racemic substrates belonging to the (RS)-2-bromo tolyl acetate ester category, but differing either in the position of the methyl substituent on the acyl part of the aromatic ring, or in the structure of the alkyl group. Lipase-catalyzed kinetic resolution via transesterification reaction between the ester and octanol in octane revealed that, of the three enzymes tested, P. cepacia lipase is the most efficient for resolution of the various racemates, with R-enantiopreference. In addition, the position of the methyl substituent was found to play a key role in governing the enantioselectivity of the reaction. Using P. cepacia lipase and 2-bromo-m/p-tolyl- or 2-bromophenylacetic acid esters E-values of 6.
- Guieysse, David,Salagnad, Christophe,Monsan, Pierre,Remaud-Simeon, Magali
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p. 317 - 323
(2007/10/03)
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- Enantioselective protonation of silyl enol ethers and ketene disilyl acetals with Lewis acid-assisted chiral Bronsted acids: Reaction scope and mechanistic insights
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Enantioselective protonation is a potent and efficient way to construct chiral carbons. Here we report details of the reaction using Lewis acid-assisted chiral Bronsted acids (chiral LBAs). The 1:1 coordinate complex of tin tetrachloride and optically active binaphthol ((R)- or (S)-BINOL) can directly protonate various silyl enol ethers and ketene disilyl acetals to give the corresponding α-aryl ketones and α-arylcarboxylic acids, respectively, with high enantiomeric excesses (up to 98% ee). A catalytic version of enantioselective protonation has also been achieved using stoichiometric amounts of 2,6-dimethylphenol and catalytic amounts of monomethyl ether of optically active BINOL in the presence of tin tetrachloride. This protonation is also effective for producing α-halocarbonyl compounds (up to 91% ee). DFT calculations on the B3LYP/LANL2DZ level show that the conformational structure of the chiral LBA and the orientation of activated proton on (R)-BINOLs are important for understanding the absolute stereochemistry of the products.
- Nakamura, Shingo,Kaneeda, Masanobu,Ishihara, Kazuaki,Yamamoto, Hisashi
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p. 8120 - 8130
(2007/10/03)
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- Dynamic kinetic resolution in the hydrolysis of an α-bromo ester
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Bromide can be employed to racemise an α-bromo ester more rapidly than the corresponding acid (carboxylate), and this rate difference has been employed as the basis of a dynamic kinetic resolution reaction.
- Jones, Matthew M.,Williams, Jonathan M. J.
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p. 2519 - 2520
(2007/10/03)
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- N-[MERCAPTOACYL(AMINO ACID OR PEPTIDE)] COMPOUNDS AND S-LIPOPHILIC ALIPHATIC CARBONYL DERIVATIVES THEREOF AS ANTIHYPERTENSIVES
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N-[Mercaptoacyl(amino acid or peptide)] compounds and S-lipophilic aliphatic carbonyl derivatives thereof, and pharmaceutical compositions comprising such compounds, as well as the use of these compounds as antihypertensives by the inhibition of neutral endopeptidase and/or peptidyldipeptidase A are disclosed. Methods for preparing the such compounds and derivatives are disclosed also.
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- Optimal recognition of neutral endopeptidase and angiotensin-converting enzyme active sites by mercaptoacyldipeptides as a means to design potent dual inhibitors
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An interesting approach for the treatment of congestive heart failure and chronic hypertension could be to avoid the formation of angiotensin II by inhibiting angiotensin converting enzyme (ACE) and to protect atrial natriuretic factor by blocking neutral endopeptidase 24.11 (NEP). This is supported by recent results obtained with potent dual inhibitors of the two zinc metallopeptidases, such as RB 105, HSCH2CH(CH3)PhCONHCH(CH3)COOH (Fournie-Zaluski et al. Proc. Natl. Acad. Sci. U.S.A. 1994, 91, 4072-4076), which reduces blood pressure in experimental models of hypertension, independently of the salt and renin angiotensin system status. In order to develop new dual inhibitors with improved affinities, long duration of action, and/or better bioavailabilities, various series of mercaptoacyldipeptides corresponding to the general formula HSCH(R1)CONHCH(R1')CON(R)CH(R2')COOH have been synthesized. The introduction of well-selected β-branched chains in positions R1 and R1', associated with a tyrosine or a cyclic amino acid in the C-terminal position, led to potent dual inhibitors of NEP and ACE such as 21 [N-[(2S)-2-mercapto- 3-methylbutanoyl]-Ile-Tyr] and 22 [N-[(2S)-2-mercapte-3-phenylpropanoyl]Ala- Pro] which have IC50 values in the nanomolar range for NEP and subnanomolar range for ACE. These compounds could have different modes of binding to the two peptidases. In NEP, the dual inhibitors seem to interact only with the S1' and S2' subsites, whereas additional interactions with the S1 binding subsite of ACE probably account for their subnanomolar inhibitory potencies for this enzyme. The localization of the Pro residue of 22 outside the NEP active site is supported by biochemical data using (Arg102,Glu)NEP and molecular modeling studies with thermolysin used as model of NEP. One hour after oral administration in mice of a single dose (2.7 x 10-5 mol/kg), 21 inhibited 80% and 36% of kidney NEP and lung ACE, respectively, while 22 inhibited 40% of kidney NEP and 56% of lung ACE.
- Coric, Pascale,Turcaud, Serge,Meudal, Hervé,Roques, Bernard Pierre,Fournie-Zaluski, Marie-Claude
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p. 1210 - 1219
(2007/10/03)
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- Optical Resolution and Asymmetric Transformation of (RS)-N-Alkyl- and (RS)-N,N-Dialkyl-2-phenylglycines
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Optical resolution of (RS)-N-methyl-2-phenylglycine and (RS)-N-ethyl-2-phenylglycine was carried out by using (1S)-10-camphorsulfonic acid as resolving agents, and that of (RS)-N-ethyl-N-methyl-2-phenylglycine by (R)- and (S)-1-phenylethylamine.Racemization rates of optically active Mpg, Epg, Emp, N,N-dimethyl-2-phenylglycine , and six α-amino acids were measured by heating in carboxylic acids.The electron-donating amino acid side chain and N-substituted alkyl group decreased therate to inhibit the formation of intermediary carbanions, whereas the electron-withdrawing side chain increased it.Asymmetric transformation of (RS)-Mpg, (RS)-Epg, and (RS)-Dmp was carried out on the basis of the results of optical resolution and racemization to give the corresponding enantiomers of approximately 100percent optical purities in over 70percent yield based on the sterting racemates.
- Shiraiwa, Tadashi,Baba, Yoshihisa,Miyazaki, Hideya,Sakata, Shinji,Kawamura, Seiko,et al.
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p. 1430 - 1437
(2007/10/02)
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- Acylmercaptoalkanoyldipeptides, methods of preparation and their therapeutic use
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This invention is directed to a compound of the formula that inhibits simultaneously neutral endopeptidase and peptidyldipeptidase A and is useful in treating hypertension. The invention is also directed to the preparation of the compound, pharmaceutical compositions containing it, and methods for its pharmaceutical use.
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