- The synthesis of S-(+)-2,2-dimethylcyclopropane carboxylic acid: A precursor for cilastatin
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S-(+)-2,2-Dimethylcyclopropane carboxylic acid, a precursor for cilastatin, was prepared from 2-methylpropene and chiral iron carbene in three steps. Asymmetric cyclopropanation reaction of 2-methylpropene with iron carbene complex having chirality at the carbene ligand, followed by exhaustive ozonolysis, produced S-(+)-2,2-dimethylcyclopropanecarboxylic acid of up to 92% ee. The absolute configuration of complexed chiral cyclopropane (-)-8 was determined by X-ray crystallographic analysis.
- Wang, Qinwei,Yang, Fukang,Du, Hong,Hossain, M. Mahmun,Bennett, Dennis,Grubisha, Desiree S.
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- Chiral 2,2-disubstituted cyclopropanecarboxylic acids: Effective derivatizing agents for analysis of enantiomeric purity of alcohols and for resolution of 1,1'-Bi-2-naphthol
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The enantiomeric purities of secondary alcohols can be easily analyzed by GC and HPLC through derivatization to the esters of 2,2-disubstituted cyclopropanecarboxylic acids 1, and by 1H NMR analysis of the esters of 2,2-diphenylcyclopropanecarboxylic acid (1b). In addition racemic 1,1'-bi-2-naphthol is easily resolved through derivatization to monoesters of 2,2-dimethylcyclopropanecarboxylic acid (1a), which are crystallized selectively and sequentially in high yields with high optical purities.
- Kim, Hyun Chang,Choi, Soojin,Kim, Hongdoo,Ahn, Kwang-Hyun,Koh, Jeong Hwan,Park, Jaiwook
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- Soluble and functional expression of a recombinant enantioselective amidase from Klebsiella oxytoca KCTC 1686 in Escherichia coli and its biochemical characterization
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A gene encoding an enantioselective amidase (KamH) was cloned from Klebsiella oxytoca KCTC 1686 and inserted into the EcoRI and HindIII sites of the vector pET-30a(+). When KamH with a peptide containing a His-tag and an enterokinase cleavage site was overexpressed in Escherichia coli, approximately half was found in the soluble fraction, but it lacked activity. After cleavage of the peptide by enterokinase, the enzyme activity was partly restored, reaching 420.2 ± 33.62 U/g dry cell weight (DCW). Another recombinant plasmid was constructed by inserting the KamH gene into the NdeI and EcoRI sites of pET-30a(+) to express KamH in its native form. The overexpressed amidase was found primarily in the soluble fraction and its maximum activity was 3613.4 ± 201.68 U/g DCW. This indicated that the peptide influenced not only soluble expression but also activity of KamH, perhaps by blocking the substrate-binding tunnel of KamH. Similar results were obtained with heterologously expressed amidases from Rhodococcus erythropolis MP50 and Agrobacterium tumefaciens d3. All of these amidases have an N-terminal α-helical domain. Therefore, amidases of this type may be functionally expressed in their native form. KamH hydrolyzed a range of aliphatic and aromatic amides and exhibited strict S-selectivity towards racemic amides.
- Guo, Fa-Mou,Wu, Jian-Ping,Yang, Li-Rong,Xu, Gang
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p. 1264 - 1271
(2015/07/08)
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- Substrate channel evolution of an esterase for the synthesis of cilastatin
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The esterase RhEst1 from Rhodococcus sp. ECU1013 has been reported for the enantioselective hydrolysis of ethyl (S)-(+)-2,2-dimethylcyclopropane carboxylate, producing the building block of cilastatin. In this work, error-prone PCR and site-directed saturation mutagenesis were applied to RhEst1 for activity improvement, with the pH-indicator assay as a high-throughput screening method. As a result, RhEst1A147I/V148F/G254A, with mutations surrounding the substrate access channel, showed a 5-fold increase in its specific activity compared with the native enzyme, as well as a 4-fold increase in protein solubility. Combined with the determination of protein structures and computational analysis, this work shows that the amino acids around the substrate channel play a more important role in the activity evolution of RhEst1 than those in the active site. This journal is
- Luan, Zheng-Jiao,Li, Fu-Long,Dou, Shuai,Chen, Qi,Kong, Xu-Dong,Zhou, Jiahai,Yu, Hui-Lei,Xu, Jian-He
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p. 2622 - 2629
(2015/05/13)
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- Production of L-tryptophan by enantioselective hydrolysis of d,l-tryptophanamide using a newly isolated bacterium
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Bacterial strain ZJB-09211 capable of amidase production has recently been isolated from soil samples. The strain is able to asymmetrically hydrolyze l-tryptophanamide from d,l-tryptophanamide to produce l-tryptophan in high yield and with excellent stereoselectivity (enantiomeric excess > 99.9 %, and enantiomeric ratio > 200). Strain ZJB-09211 has been identified as Flavobacterium aquatile based on the cell morphology analysis, physiological tests, and the 16S rDNA sequence analysis. Optimization of the fermentation medium led to an about six-fold increase in the amidase activity of strain ZJB-09211, which reached 501.5 U L-1. Substrate specifity and stereoselectivity investigations revealed that amidase of F. aquatile possessed a broad substrate spectrum and high enantioselectivity.
- Xu, Jian-Miao,Chen, Ben,Wang, Yuan-Shan,Zheng, Yu-Guo
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p. 1262 - 1270
(2013/07/19)
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- PROCESS FOR PRODUCTION OF OPTICALLY ACTIVE CARBOXYLIC ACID
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The invention provides a process for producing optically active 2, 2-dimethylcyclopropanecarboxylic acid by reacting an optical isomer mixture of 2,2-dimethylcyclopropanecarboxylic acid with an optically inactive amine to form (precipitate, crystallize or the like) an ammonium salt of optically active 2,2-dimethylcyclopropanecarboxylic acid, for example, optically active (S)-(+)-2,2-dimethylcyclopropanecarboxylic acid. The production (optical resolution, separation of an optically active substance, purification of an optically active substance or the like) of optically active 2, 2-dimethylcyclopropanecarboxylic acid which is important as an intermediate for production of agricultural chemicals, medications and the like can easily be conducted at low cost. Further, the invention provides an intermediate therefor (an ammonium salt of optically active 2,2-dimethylcyclopropanecarboxylic acid, especially preferably an ammonium salt of optically active (S)-(+)-2,2-dimethylcyclopropanecarboxylic acid, or the like), and an optical resolution agent (optically inactive amine) for separation of optically active 2,2-dimethylcyclopropanecarboxylic acid.
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- PROCESS FOR PRODUCING OPTICALLY ACTIVE AMIDE
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The present invention relates to a new process for preparing a medical intermediate compound of formula (I). According to the present invention, an intermediate compound for cilastatin can be simply prepared with a high yield of 99.0% or more and a high optical purity of 99.5% without undergoing any dangerous processes.
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- Highly Enantioselective Intermolecular Cyclopropanation Catalyzed by Dirhodium(II) Tetrakis[3(S)-phthalimido-2-piperidinonate]: Solvent Dependency of the Enantioselection
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The enantioselectivity in cyclopropanations catalyzed by dirhodium(II) tetrakis[3(S)-phthalimido-2-piperidinonate] has been found to be substantially improved by employing ether as the rarely used solvent. Cyclopropanations of styrenes or 1,1-disubstituted alkenes with 2,4-dimethyl-3-pentyl diazoacetate in ether are promoted by this catalyst to afford the corresponding cyclopropane products in the highest levels of enantioselectivity (up to 98% ee) reported to date for the dirhodium(II)-catalyzed intermolecular cyclopropanation reactions.
- Kitagaki, Shinji,Matsuda, Hideo,Watanabe, Nobuhide,Hashimoto, Shun-Ichi
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p. 1171 - 1174
(2007/10/03)
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- Asymmetric Cyclopropanation Using New Chiral Auxiliaries Derived from D-Fructose
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Acetals of α,β-unsaturated aldehydes with 3-O-alkylated derivatives of 1,2-O-isopropylidene-β-D-fructopyranose and 1,2-O-isopropylidene-β-D-psicopyranose, which are readily available from D-fructose, were cyclopropanated with Et2Zn and CH2I2 with good diastereoselectivity.The effects of structure of the acetals on enantioselectivity were examined.
- Kang, Jahyo,Lim, Geun Jho,Yoon, Suk Kyoon,Kim, Moohi Yoo
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p. 564 - 577
(2007/10/02)
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- Process for resolution of racemates of 2,2-dimethylcyclopropanecarboxylic acid
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The enantiomers of 2,2-dimethylcyclopropanecarboxylic acid are separated by salt formation with optically active 1-(3-methoxyphenyl)-ethylamine, fractional crystallization of the diastereomeric salts and subsequent decomposition of the salts with a strong acid.
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- Inhibition of the Mammalian β-Lactamase Renal Dipeptidase (Dehydropeptidase-I) by (Z)-2-(Acylamino)-3-substituted-propenoic Acids
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The title enzyme deactivates the potent carbapenem antibiotic imipenem in the kidney, producing low antibiotic levels in the urinary tract.A series of (Z)-2-(acylamino)-3-substituted-propenoic acids (3) are specific, competitive inhibitors of the enzyme capable of increasing the urinary concentration of imipenem in vivo.Many of the compounds were prepared in one step from an α-keto acid and a primary amide.The optimum R2 groups are 2,2-dimethyl, -dichloro, and -dibromocyclopropyl.With R2 = 2,2-dimethylcyclopropyl (DMCP), a wide variety of R3 groups including alkyl, oxa- and thiaalkyl, and alkyl groups containing acidic, basic, and neutral substituents give effective inhibitors with Ki values of 0.02-1 μM and a range of pharmacokinetic properties.By resolution of enantiomers and X-ray crystallography, the enzyme-inhibitory activity of the DMCP group was found to reside with the 1S isomer.The cysteinyl compound 176 (cilastatin, MK-0791) has the desired pharmacological properties and has been chosen for combination with imipenem.
- Graham, Donald W.,Ashton, Wallace T.,Barash, Louis,Brown, Jeannette E.,Brown, Ronald D.,et al.
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p. 1074 - 1090
(2007/10/02)
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