- The kinetic resolution of oxazinones by alcoholysis: access to orthogonally protected β-amino acids
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The catalytic, alcoholytic kinetic resolution of oxazinones is reported. A novel, stereochemically dense cinchona alkaloid-based catalyst can facilitate the highly enantiodiscriminatory (Sup to 101) ring-opening of oxazinones equipped with electrophilic aryl units to generate orthogonally protected β-amino acids for the first time.
- Connon, Stephen J.,Cronin, Sarah A.
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supporting information
p. 7348 - 7352
(2021/09/07)
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- Catalytic asymmetric oxidative carbonylation-induced kinetic resolution of sterically hindered benzylamines to chiral isoindolinones
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A highly enantioselective kinetic resolution of sterically hindered benzylamines has been achieved for the first time through transition-metal-catalyzed oxidative carbonylation, in which the new KR strategy offered a new approach to afford chiral isoindolinones (er up to 97?:?3) and the origin of chemoselectivity and stereoselectivity was confirmed by density functional theory (DFT) calculations.
- Mu, Qiu-Qi,Nie, Yi-Xue,Li, Hang,Bai, Xing-Feng,Liu, Xue-Wei,Xu, Zheng,Xu, Li-Wen
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supporting information
p. 1778 - 1781
(2021/02/27)
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- Base-induced Sommelet–Hauser rearrangement of N-(α-(2-oxyethyl)branched)benzylic glycine ester-derived ammonium salts via a chelated intermediate
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The base-induced Sommelet–Hauser (S–H) rearrangement of N-(α-branched)benzylic glycine ester-derived ammonium salts 1 was investigated. When the α-branched substituent was a simple alkyl, such as a methyl or butyl, desired S–H rearrangement product 2 was obtained in low yield with formation of the [1,2] Stevens rearranged 4 and Hofmann eliminated products 5 and 6. However, when the α-branched substituent had a 2-oxy moiety, such as 2-acetoxyethyl or 2-benzoyloxyethyl, the yields of 2 were improved. These results could be explained by formation of chelated intermediate C that stabilizes the carbanionic ylide, and the subsequent initial dearomative [2,3] sigmatropic rearrangement would be accelerated. The existence of C was supported by mechanistic experiments. This enhancement effect is not very strong or effective; however, it will expand the synthetic usefulness of ammonium ylide rearrangements.
- Baba, Souya,Hirano, Kazuki,Tayama, Eiji
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supporting information
(2020/03/13)
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- Phenyl-oxamideHIV-1 inhibitors and preparation method and application thereof
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The invention relates to phenyl-oxamideHIV-1 inhibitors and a preparation method and application thereof. Compounds have the structure shown in the formula I. The invention further relates to drug compositions containing the compounds with the structure s
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Paragraph 0023; 0089-0090
(2019/07/04)
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- Synthesis, molecular docking and biological evaluation of novel phthaloyl derivatives of 3-amino-3-aryl propionic acids as inhibitors of Trypanosoma cruzi trans-sialidase
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In the last two decades, trans-sialidase of Trypanosoma cruzi (TcTS) has been an important pharmacological target for developing new anti-Chagas agents. In a continuous effort to discover new potential TcTS inhibitors, 3-amino-3-arylpropionic acid derivatives (series A) and novel phthaloyl derivatives (series B, C and D) were synthesized and molecular docking, TcTS enzyme inhibition and determination of trypanocidal activity were carried out. From four series obtained, compound D-11 had the highest binding affinity value (?11.1 kcal/mol) compared to reference DANA (?7.8 kcal/mol), a natural ligand for TS enzyme. Furthermore, the 3D and 2D interactions analysis of compound D-11 showed a hydrogen bond, π-π stacking, π-anion, hydrophobic and Van der Waals forces with all important amino acid residues (Arg35, Arg245, Arg314, Tyr119, Trp312, Tyr342, Glu230 and Asp59) on the active site of TcTS. Additionally, D-11 showed the highest TcTS enzyme inhibition (86.9% ± 5) by high-performance ion exchange chromatography (HPAEC). Finally, D-11 showed better trypanocidal activity than the reference drugs nifurtimox and benznidazole with an equal % lysis (63 ± 4 and 65 ± 2 at 10 μg/mL) and LC50 value (52.70 ± 2.70 μM and 46.19 ± 2.36 μM) on NINOA and INC-5 strains, respectively. Therefore, D-11 is a small-molecule with potent TcTS inhibition and a strong trypanocidal effect that could help in the development of new anti-Chagas agents.
- Kashif, Muhammad,Chacón-Vargas, Karla Fabiola,López-Cedillo, Julio Cesar,Nogueda-Torres, Benjamín,Paz-González, Alma D.,Ramírez-Moreno, Esther,Agusti, Rosalia,Uhrig, Maria Laura,Reyes-Arellano, Alicia,Peralta-Cruz, Javier,Ashfaq, Muhammad,Rivera, Gildardo
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p. 252 - 268
(2018/07/14)
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- Kinetic Resolution of Aromatic β-Amino Acids Using a Combination of Phenylalanine Ammonia Lyase and Aminomutase Biocatalysts
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An enzymatic strategy for the preparation of (R)-β-arylalanines employing phenylalanine aminomutase and ammonia lyase (PAM and PAL) enzymes has been demonstrated. Candidate PAMs with the desired (S)-selectivity from Streptomyces maritimus (EncP) and Bacillus sp. (PabH) were identified via sequence analysis using a well-studied template sequence. The newly discovered PabH could be linked to the first ever proposed biosynthesis of pyloricidin-like secondary metabolites and was shown to display better β-lyase activity in many cases. In spite of this, a method combining the higher conversion of EncP with a strict α-lyase from Anabaena variabilis (AvPAL) was found to be more amenable, allowing kinetic resolution of five racemic substrates and a preparative-scale reaction with >98% (R) enantiomeric excess. This work represents an improved and enantiocomplementary method to existing biocatalytic strategies, allowing simple product separation and modular telescopic combination with a preceding chemical step using an achiral aldehyde as starting material. (Figure presented.).
- Weise, Nicholas J.,Ahmed, Syed T.,Parmeggiani, Fabio,Turner, Nicholas J.
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supporting information
p. 1570 - 1576
(2017/05/05)
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- Synthesis and biological evaluation of 3-phenyl-3-aryl carboxamido propanoic acid derivatives as small molecule inhibitors of retinoic acid 4-hydroxylase (CYP26A1)
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All-trans-retinoic acid (ATRA), the biologically active metabolite of vitamin A, is used medicinally for the treatment of hyperproliferative diseases and cancers. However, it is easily metabolized. In this study, the leading compound S8 was found based on virtual screening. To improve the activity of the leading compound S8, a series of novel S8 derivatives were designed, synthesized and evaluated for their in vitro biological activities. All of the prepared compounds showed that substituting the 5-chloro-3-methyl-1-phenyl-1H-pyrazole group for the 2-tertbutyl-5-methylfuran scaffold led to a clear increase in the biological activity. The most promising compound 32, with a CYP26A1 IC50 value of 1.36 μM (compared to liarozole (IC50 = 2.45 μM) and S8 (IC50 = 3.21 μM)) displayed strong inhibitory and differentiation activity against HL60 cells. In addition, the study focused on the effect of β-phenylalanine, which forms the coordination bond with the heme of CYP26A1. These studies suggest that the compound 32 can be used as an appropriate candidate for future development.
- Zhao, Dongmei,Sun, Bin,Ren, Jinhong,Li, Fengrong,Song, Shuai,Lv, Xuejiao,Hao, Chenzhou,Cheng, Maosheng
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p. 1356 - 1365
(2015/03/04)
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- Enantioselective acylation of β-phenylalanine acid and its derivatives catalyzed by penicillin G acylase from alcaligenes faecalis
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This study developed a simple, efficient method for producing racemic β-phenylalanine acid (BPA) and its derivatives via the enantioselective acylation catalyzed by the penicillin G acylase from Alcaligenes faecalis (Af-PGA). When the reaction was run at 25°C and pH 10 in an aqueous medium containing phenylacetamide and BPA in a molar ratio of 2:1, 8 U/mL enzyme and 0.1 M BPA, the maximum BPA conversion efficiency at 40 min only reached 36.1%, which, however, increased to 42.9% as the pH value and the molar ratio of phenylacetamide to BPA were elevated to 11 and 3:1, respectively. Under the relatively optimum reaction conditions, the maximum conversion efficiencies of BPA derivatives all reached about 50% in a relatively short reaction time (45-90 min). The enantiomeric excess value of product (eep) and enantiomeric excess value of substrate (ees) were all above 98% and 95%, respectively. These results suggest that the method established in this study is practical, effective, and environmentally benign and may be applied to industrial production of enantiomerically pure BPA and its derivatives.
- Li, Dengchao,Ji, Lilian,Wang, Xinfeng,Wei, Dongzhi
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p. 207 - 216
(2013/04/23)
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- Kinetic resolution of aromatic β-amino acids by ω-transaminase
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Racemic aromatic β-amino acids have been kinetically resolved into (R)-β-amino acids with high enantiomeric excess (>99%) by a novel ω-TA with ca. 50% conversion.
- Bea, Han-Seop,Park, Hye-Jeong,Lee, Sang-Hyeup,Yun, Hyungdon
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supporting information; experimental part
p. 5894 - 5896
(2011/06/23)
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- Stereoselective chemoenzymatic preparation of β-amino esters: Molecular modelling considerations in lipase-mediated processes and application to the synthesis of (S)-dapoxetine
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A wide range of optically active 3-amino-3-arylpropanoic acid derivatives have been prepared by means of a stereoselective chemoenzymatic route. The key step is the kinetic resolution of the corresponding β-amino esters. Although the enzymatic acylations of the amino group with ethyl methoxyacetate showed synthetically useful enantioselectivities, the hydrolyses of the ester group catalyzed by lipase from Pseudomonas cepacia have been identified as the optimal processes concerning both activity and enantioselectivity. The enantiopreference of this lipase in these reactions has been explained, at the molecular level, by using a fragment-based approach in which the most favoured binding site for a phenyl ring and the most stable conformation of the 3-aminopropanoate core nicely match the (S)-configuration of the major products. The conversion and enantioselectivity values of the enzymatic reactions have been compared in order to understand the influence of the different substitution patterns present in the phenyl ring. This chemoenzymatic route has been successfully applied to the preparation of a valuable intermediate in the synthesis of (S)-dapoxetine, which has been chemically synthesised in excellent optical purity.
- Rodriguez-Mata, Maria,Garcia-Urdiales, Eduardo,Gotor-Fernandez, Vicente,Gotor, Vicente
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supporting information; experimental part
p. 395 - 406
(2010/06/15)
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- 3-AMINO-3-ARYLPROPIONIC ACID n-ALKYL ESTERS, PROCESS FOR PRODUCTION THEREOF, AND PROCESS FOR PRODUCTION OF OPTICALLY ACTIVE 3-AMINO-3-ARYLPROPIONIC ACIDS AND ESTERS OF THE ANTIPODES THERETO
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The present invention is to provide an n-alkyl 3-amino-3-arylpropionate represented by the formula (I): wherein Ar1 represents an aryl group which may have a substituent(s), provided that a phenyl group and 4-methoxyphenyl group are excluded, R1 represents an n-propyl group or an n-butyl group, and a process for preparing the same, and its optically active compound and an optically active (S or R)-3-amino-3-arylpropionic acid represented by the formula (III-a): wherein Ar represents an aryl group which may have a substituent(s), and * represents an asymmetric carbon, and a process for preparing an optically active n-alkyl (R or S)-3-amino-3-arylpropionate represented by the formula (IV-a): wherein Ar and R1 have the same meanings as defined above, * represents an asymmetric carbon, provided that it has a reverse absolute configuration to the compound of the formula (III-a).
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Page/Page column 40
(2008/06/13)
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- Competitive formation of β-amino acids, propenoic, and ylidenemalonic acids by the Rodionov reaction from malonic acid, aldehydes, and ammonium acetate in alcoholic medium
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The Rodionov reaction of 49 available aliphatic and aromatic aldehydes with malonic acid and ammonium acetate in alcoholic medium, resulting in formation of β-amino acids, propenoic, and ylidenemalonic acids, was studied. Certain regioselectivity regularities of the reaction were revealed. Among the variety of ketones studied, cyclohexanone is the only whose reaction yields a β-amino acid. Unusual dehydrofluorination of 6-chloro-2-fluorocinnamic acid under the Rodionov reaction was discovered. 2005 Pleiades Publishing, Inc.
- Lebedev,Lebedeva,Sheludyakov,Kovaleva,Ustinova,Kozhevnikov
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p. 1113 - 1124
(2007/10/03)
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- Kinetic resolution of oxazinones: An organocatalytic approach to enantiomerically pure β-amino acids
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(Chemical Equation Presented) A profitable split: An organocatalytic resolution converts readily available racemic oxazinones 1 into valuable enantiomerically pure β-amino acid derivatives 2 (> 99% ee of the remaining 1 at 53% conversion; 88% ee of the ester 2). This catalytic ring-opening reaction requires as little as 1 mol% of the modular and readily accessible thiourea organocatalyst 3.
- Berkessel, Albrecht,Cleemann, Felix,Mukherjee, Santanu
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p. 7466 - 7469
(2007/10/03)
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- A one-pot synthesis of 3-amino-3-arylpropionic acids
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3-Aminopropionic acids (β-amino acids) are biologically active compounds of interest in medicinal and pharmaceutical chemistry. Twenty-one 3-amino-3-arylpropionic acids were synthesized via a facile one-pot synthesis. In addition, a series of mechanistic studies have been performed to optimize the production of these β-amino acids. The reaction mechanism of this one-pot synthesis of β-amino acids, as well as the electronic effect of para-substitution and the influence of solvent polarity on the proposed reaction mechanism are discussed.
- Tan,Weaver
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p. 7449 - 7461
(2007/10/03)
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- Aromatic β-amino acids as Asp-Phg mimics in LDV derived VLA-4 antagonists
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Aromatic β-amino acid esters 2a-h were prepared in racemic and enantiomerically pure form by the Radionow reaction or based on the method described by Davis and used as mimics of the Asp-Phg C-terminus in LDV derived VLA-4 antagonists. As a promising β-am
- Wehner, Volkmar,Blum, Horst,Kurz, Michael,Stilz, Hans Ulrich
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p. 2023 - 2036
(2007/10/03)
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- A new and expeditious strategy for the synthesis of β-amino acids from Δ2-oxazolines
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A new, mild two-step synthesis of racemic β-amino acids starting from 2-alkyl-Δ2-oxazolines is described. The process implies the initial formation of masked N-substituted or N-unsubstituted β-enamino acid derivatives followed by chemoselective reduction of the enamino moiety. The process takes place with high yields, total chemoselectivity and moderate diastereoselectivity.
- Fustero, Santos,Díaz, Ma Dolores,Navarro, Antonio,Salavert, Esther,Aguilar, Enrique
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p. 703 - 712
(2007/10/03)
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- Solid-phase synthesis of a nonpeptide RGD mimetic library: New selective αvβ3 integrin antagonists
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The solid-phase synthesis of a low molecular weight RGD mimetic library is described. Activities of the compounds in inhibiting the interaction of ligands, vitronectin and fibrinogen, with isolated immobilized integrins αvβ3 and αIIbβ3 were determined in a screening assay. Highly active and selective nonpeptide αvβ3 integrin antagonists with regard to orally bioavailability were developed, based on the aza-glycine containing lead compound 1. An important variation is the substitution of the aspartic amide of 1 by an aromatic residue. Furthermore, different guanidine mimetics have been incorporated to improve the pharmacokinetic profile. Exchange of the β-amino acid NH by a methylene moiety in one set of RGD mimetics leads to the azacarba analogue compounds representing a novel peptidomimetic approach, which should increase the metabolic stability.
- Sulyok,Gibson,Goodman,H?lzemann,Wiesner,Kessler
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p. 1938 - 1950
(2007/10/03)
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- Design and preparation of serine-threonine protein phosphatase inhibitors based upon the nodularin and microcystin toxin structures. Part 3
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Nodularin and microcystins are complex natural cyclic isopeptidic hepatotoxins that serve as subnanomolar inhibitors of the eukaryotic serine-threonine protein phosphatases PP1 and PP2A, enzymes that are intimately involved in controlling cellular metabolism. Previously we described a solution-phase synthesis of stripped-down nodularin analogues; cyclo[-β-Ala-(R)-Glu-α-OMe-γ-Sar-(R)-Asp-α-OMe- β-(S)-Phe-] 3 and cyclo[-(3R)-3-hydroxymethyl-β-Ala-(R)-Glu-α-OMe-γ-Sar-(R)- Asp-α-OMe-β-(S)-Phe-] 5. The synthetic strategy was designed to allow post-macrocyclisation elaboration. Here we examine alternative methods for introducing diversity and achieving macrolactamisation and compare the relative efficiency of solution- vs. solid-phase peptide syntheses of the macrocycles. Syntheses and the biological activities of the macrocycles cyclo{-[(2R)-α-4-benzylpiperidinylamido-Asp]-β-[(R)-Glu]-γ- Sar-[(R)-Asp]-β-(S)-Phe-} 29 and cyclo{-(2S)-Phe-[(2R)-α-4-benzylpiperidinylamido-Asp]-(R)-Glu-γ- (S)-Pro-β-(R)-Asp-} 65 are compared. Both compounds contain sufficient side-chain functionality to interact with a hydrophobic groove at the enzyme active site. The proline containing analogues 30, 31 (R3 = CH3) where sarcosine is replaced in macrocycles 3 and 4, were also synthesised in order to correlate conformational properties with biological activity. In accord with predictions macrocycles 29 and 65 were found to be weak inhibitors of PP1 with IC50 2.9 and 2.7 mM respectively.
- Webster,Maude,O'Donnell,Mehrotra,Gani
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p. 1673 - 1695
(2007/10/03)
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- Addition of a Reformatsky Reagent to N-Anthracene-9-sulfonyl and Related Imines: Synthesis of Protected β-Amino Acids
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The Reformatsky reagent tert-butoxycarbonylmethylzinc bromide adds in high yields to N-sulfonylimines, e.g. 1a-1d, derived by condensation of benzaldehyde dimethyl acetal with methanesulfonamide, toluene-4-sulfonamide, 4-(methoxycarbonyl)benzenesulfonamide and sulfamide: the products are protected β-amino acids 2a-2d.N-Deprotection occurs reductively (Na-naphthalene; low yields) for 2b and 2c or hydrolytically (refluxing aq. pyridine; 76percent yield of amino acid 3a after acid hydrolysis of the t-butyl ester) for the sulfamide derivatives 2d.Anthracene-9-sulfonamide (6) is readily available by sulfonation and chlorination of anthracene, and condenses with aldehydes , e.g. in the presence of TiCl4/Et3N, to yield imines 7a-7f, which after addition of tert-butoxycarbonylmethylzinc bromide give protected amino acids 8a-8f; however, 8f cyclizes to the sultam 9 via a spontaneous intramolecular Diels-Alder reaction.Reductive cleavage of the N-anthracene-9-sulfonyl group is much easier than for traditional N-sulfonyl protecting groups, as demonstrated by the deprotection of 8a and 8c using aluminium amalgam.
- Robinson, Andrew J.,Wyatt, Peter B.
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p. 11329 - 11340
(2007/10/02)
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- Substituted aryl ureas as high potency sweeteners
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Substituted ureas and thioureas are disclosed for use as high potency sweeteners.
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- SYNTHESIS OF 6-ARYL-4-HYDROXYPIPERIDIN-2-ONES AND A POSSIBLE APPLICATION TO THE SYNTHESIS OF A NOVEL HMG-CoA REDUCTASE INHIBITOR
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A series of 6-aryl-4-hydroxypiperidin-2-ones (11a-11g) were synthesised with the key step being a Dieckmann cyclisation of the appropriate methyl 3-(ethoxycarbonylacetylamino)-3-(substituted) propionate (8a-8g) and this new synthetic route was successfully applied to the synthesis of 4-hydroxy-6-(2-phenylethyl)piperidin-2-one (11h).The application of this strategy to the synthesis of the putative HMG-CoA reductase inhibitor 6--4-hydroxypiperidin-2-one (11i) was attempted, but failed during the Dieckmann cyclisation of methyl 3-(ethoxycarbonylacetylamino)- 3-propionate (8i).An alternative synthesis of a 1:1 diastereomeric mixture of (11i) was achieved by the reductive cleavage of the isoxazoline (24) with Raney nickel.The mixture of diastereoisomers (11i) was inactive in-vitro and in-vivo (rat) against HMG-CoA reductase
- Ashton, Michael J.,Hills, Susan J.,Newton, Christopher G.,Taylor, John B.,Tondu, Sylvie C. D.
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p. 1015 - 1035
(2007/10/02)
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- Une synthese simple des premieres amino-3 indanones-1
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The synthesis of various substituted 3-amino-1-indanones was achieved in five steps starting from corresponding benzaldehydes.
- Rault, Sylvain,Dallemagne, Patrick,Robba, Max
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p. 1079 - 1083
(2007/10/02)
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- Synthesis of (4R)-D,L-- and (4S)-D,L-Homoserine Lactones
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The (4R)-D,L-- and (4S)-D,L-homoserine lactone hydrochloride salts were prepared from D,L-3-amino-3-(4-methoxyphenyl)propanoic acid (1) in eight steps in an overall yields of 5.0percent.Amino acid 1 was converted into D,L-3-(1,1-dimethyletho
- Kalvin, Douglas M.,Woodard, Ronald W.
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p. 2259 - 2263
(2007/10/02)
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