- METHOD FOR OBTAINING OPTICALLY PURE AMINO ACIDS
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This invention relates to a method for obtaining optically pure amino acids, including optical resolution and optical conversion. This method significantly shortens the time taken for optical transformation, and enables the repeated use of an organic solution containing a enantioselective receptor, to thereby obtain optically pure amino acids in a simple and remarkably efficient manner, and to enable the very economical mass production of optically pure amino acids.
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Page/Page column 7
(2012/02/01)
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- Thermal cleavage of the Fmoc protection group
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The Fmoc protection group is among the most commonly used protection groups for the amino function. A fast method for the thermal deavage of this protection group under base-free conditions without the need for dibenzofulvene scavengers is presented. The advantages of this method include straightforward testability by means of a simple high-temperature NMR experiment, usually high yields, and good selectivity towards the BOC protection group and t-butyl ethers.
- Hoeck, Stefan,Marti, Roger,Riedl, Rainer,Simeunovic, Marina
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experimental part
p. 200 - 202
(2011/08/05)
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- HETEROCYCLIC MODULATORS OF PKB
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The invention relates to heterocyclic compounds of Formula I and compositions thereof useful for treating diseases mediated by protein kinase B (PKB) where the variables have the definitions provided herein Formula (I). The invention also relates to the therapeutic use of such compounds and compositions thereof in treating disease states associated with abnormal cell growth, cancer, inflammation, and metabolic disorders.
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Page/Page column 136
(2009/03/07)
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- Burkholderia cepacia lipase and activated β-lactams in β-dipeptide and β-amino amide synthesis
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The work describes fluorine-activated and N-Boc-activated β-lactams as acyl donors to N-nucleophiles in the presence of Burkholderia cepacia lipase (lipase PS-D). Fluorine activation at the β-lactam ring causes the ring to open in high enantioselectivity
- Li, Xiang-Guo,Laehitie, Maria,Kanerva, Liisa T.
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p. 1857 - 1861
(2008/12/21)
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- Synthesis of a β-tetrapeptide analog as a mother compound for the development of matrix metalloproteinase-2-imaging agents
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Matrix metalloproteinase-2 (MMP-2) is an attractive target for the diagnosis of cancer and atherosclerosis in nuclear imaging. A cyclic decapeptide, cCTTHWGFTLC (cCTT), has been used as the mother compound for the development of MMP-2-imaging agents with high potency and selectivity. Most of radiolabeled derivatives of cCTT currently developed for in vivo studies of MMP-2, however, suffer from low accumulation in the target tissues, such as tumors. For enhanced in vivo stability and tissue penetration, we designed a linear β-tetrapeptide analog, H-β3-Phe-β-Ala- β3-Trp-β3-His-OH (1), to mimic cCTT. The component β-amino acids were prepared by reduction of N-protected α-amino acid methyl esters to the alcohols, followed by conversion into the cyanides, and subsequent hydrolysis. Compound 1 was obtained from these β-amino acids by the conventional solution method. In MMP-2 inhibition assay, compound 1 displayed desirably significant inhibition, which was comparable to cCTT. These findings suggest that compound 1 may serve as a mother compound in the design and development of in vivo MMP-2-imaging agents.
- Mukai, Takahiro,Suganuma, Noriko,Soejima, Kenta,Sasaki, Junichi,Yamamoto, Fumihiko,Maeda, Minoru
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p. 260 - 265
(2008/09/21)
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- Candida antarctica lipase B-catalyzed ring opening of 4-arylalkyl-substituted β-lactams
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The Lipolase-catalyzed ring opening of racemic 4-benzyl- 3 and 4-phenylethyl-2-azetidinone 4 was performed with 0.5 equiv of H2O in diisopropyl ether at 45 °C. The resulting (S)-β-amino acid 5 or 6 (ee ≥ 87%) and (R)-β-lactam 7 or 8 (ee >99%) enantiomers could easily be separated. The ring opening of enantiomeric β-lactams with 18% aqueous HCl afforded the corresponding enantiopure β-amino acid hydrochlorides 9 and 10 (ee >99%).
- Tasnadi, Gabor,Forro, Eniko,Fueloep, Ferenc
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p. 2841 - 2844
(2008/03/28)
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- Novel compounds that inhibit dipeptidyl peptidase (DPP-IV) and neprilysin (NEP) and/or angiotensin converting enzyme (ACE)
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This invention relates to novel compounds, compositions containing the compounds, that inhibit dipeptidyl peptidase (especially DPP-IV) and neprilysin (NEP, neutral endopeptidase) as well as dipeptidyl peptidase (especially DPP-IV) and angiotensin converting enzyme (ACE) and/or dipeptidyl Peptidase (especially DPP-IV) and vasopeptidases (especially ACE and NEP). These compounds and pharmaceutical compositions thereof are useful for the treatment as well as the prevention of type 2 diabetes mellitus.
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Page/Page column 13
(2010/10/20)
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- Lipase-involved strategy to the enantiomers of 4-benzyl-β-lactam as a key intermediate in the preparation of β-phenylalanine derivatives
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A simple chemoenzymatic method for the preparation of the enantiomers of 4-benzyl-β-lactam (4-benzylazetidin-2-one) from allylbenzene has been described. The enantiomers of this key intermediate have been used to produce the corresponding enantiomers of β-phenylalanine and N-Boc-protected β-phenylalanine amide through the simple cleavage of the lactam ring by acid-catalyzed hydrolysis and by ammonolysis, respectively. Burkholderia cepacia lipase-catalyzed kinetic double resolution techniques were responsible for achieving enantiopurity in the products. This was performed through the acylation of N-hydroxymethylated β-lactam followed by the butanolysis of the obtained (S)-ester. Direct lipase-catalyzed cleavage of the β-lactam ring has also been studied.
- Li, Xiang-Guo,Kanerva, Liisa T.
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p. 197 - 205
(2007/10/03)
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- Azetidinone derivatives for the treatment of HCMV infections
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A compound of formula I wherein R1is hydrogen, methyl, ethyl, methoxy or methylthio; R2and R3each independently is hydrogen or lower alkyl; R4is hydrogen, lower alkyl, methoxy, ethoxy or benzyloxy; R5is lower alkyl, lower cycloalkyl, (CH2)mC(O)OR6wherein m is the integer 1 or 2 and R6is lower alkyl, phenyl optionally substituted; optionally Het or Het(lower alkyl); or R4and R5together with the nitrogen atom to which they are attached form a nitrogen containing ring optionally substituted with C(O)O-benzyl or with phenyl optionally substituted with C(O)OR7wherein R7is lower alkyl or (lower alkyl)phenyl; and Z is lower alkyl or optionally substituted phenyl or Het; with the proviso that when Z is (CH2)p-(Het), then R2and R3each is hydrogen; or a therapeutically acceptable acid addition salt thereof which compound is useful in the treatment of HCMV infections.
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- β-Casomorphins: Substitution of phenylalanine with β-homo phenylalanine increases the μ-type opioid receptor affinity
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Two analogues of bovine β-casomorphin-7 and β-casomorphin-5 containing a β-homo phenylalanine in substitution of the phenylalanine in position 3 were synthesised and tested for their μ-opioid receptor affinity. The modification enhanced the μ receptor affinity 5-fold in the case of modified β-CM-7 and 2-fold for modified β-CM-5 when compared to the natural peptides. (C) 2000 Elsevier Science Ltd. All rights reserved.
- Longobardo, Luigi,Melck, Dominique,Siciliano, Rosa,Santini, Antonello,Marzo, Vincenzo Di,Cammarota, Giancarlo
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p. 1185 - 1188
(2007/10/03)
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- Chemoenzymatic synthesis of 4-amino-2-hydroxy acids: A comparison of mutant and wild-type oxidoreductases
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We describe a new chemoenzymatic synthesis of enantiopure 4-amino-2-hydroxy acids using two biotransformations in a single-pot process in aqueous medium. These compounds are valuable as γ-turn mimics for investigations into the secondary structure of peptides. The enzyme substrates are a series of carbobenzyloxy (CBZ)-protected 4-amino-2-keto esters, prepared efficiently from the L-amino acids, alanine, leucine, phenylalanine, and valine. First, the α-amino acids were converted to the corresponding β-amino acids in a simple five-step procedure. A further one-carbon homologation via ozonolysis of the corresponding β-keto cyanophosphoranes gave the required α-keto esters in good yield. The enzyme catalyzed hydrolyses of all the α-keto esters to the corresponding α-keto acids proceeded smoothly with the lipase from Candida rugosa. Using the same reaction pot, it was found that wild-type lactate dehydrogenases from either Bacillus stearothermophilus CBS-LDH) or Staphylococcus epidermidis (SE-LDH) could be used to specifically reduce the ketone of the alanine-derived α-keto acid 2, giving the (S)- and CR)-2-hydroxy acids, respectively, in good yields. However, the more bulky α-keto acids 3, 4, and 5 (derived from valine, leucine, and phenylalanine) were not substrates for these enzymes. In contrast, the genetically engineered H205Q mutant of D-hydroxyisocaproate dehydrogenase proved to be an ideal catalyst for the reduction of all the α-keto acids 2-5, giving excellent yields of the CBZ-protected (2R,4S)-4-amino2-hydroxy acids as single diastereomers. This genetically engineered oxidoreductase has great potential value in synthesis due to its broad substrate specificity and high catalytic activity. For example, reduction of 1 mmol of N-protected (S)-4-amino-2-oxopentanoic acid 2 took just 4 h with the H205Q mutant giving, after esterification, the CR)-2-alcohol 25 in 85% yield, whereas with SE-LDH the reaction required 4 days to give a 67% yield of 25.
- Sutherland, Andrew,Willis, Christine L.
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p. 7764 - 7769
(2007/10/03)
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- β-lactam derivatives as inhibitors of human cytomegalovirus protease
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The development of novel monobactam inhibitors of HCMV protease incorporating a carbon side chain at C-4 and a urea function at N-1 is described. Substitution with small groups at the C-3 position of the β- lactam ring gave an increase in enzymatic activity and in stability; however, a lack of selectivity against other serine proteases was noted. The use of both triand tetrasubstituted urea functionalities gave effective inhibitors of HCMV protease. Benzyl substitution of the urea moiety was beneficial, especially when strong electron-withdrawing groups where attached at the para position. Modest antiviral activity was found in a plaque reduction assay.
- Yoakim, Christiane,Ogilvie, William W.,Cameron, Dale R.,Chabot, Catherine,Guse, Ingrid,Haché, Bruno,Naud, Julie,O'Meara, Jeff A.,Plante, Raymond,Déziel, Robert
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p. 2882 - 2891
(2007/10/03)
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- Self-reproduction of chirality. Asymmetric synthesis of β-alkyl-β-amino acids from enantiomerically pure dihydropyrimidinones
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Enantiomerically pure heterocycle 2 is deprotonated at C6 with tert-butyllithium at -78°C. The resulting carbanion reacts with alkyl halides and aldehydes to give the corresponding alkylated products. Reduction of the double bond followed by hydrolysis affords enantiomerically pure β-alkyl-β-amino acids.
- Chu, Kent S.,Konopelski, Joseph P.
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p. 9183 - 9190
(2007/10/02)
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- SYNTHESIS OF DIAZOKETONES DERIVED FROM α-AMINO ACIDS; PROBLEM OF SIDE REACTIONS
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Optimum conditions of synthesis of eight diazoketones derived from optically active N-(t-butyloxycarbonyl)- and N-benzyloxycarbonylamino acids have been described.The problem of formation of by-products during Arndt-Eistert synthesis of β-homoamino acids at the stage of reaction of mixed anhydride with a weak nucleophile-diazomethane - has been discussed.
- Plucinska, Krystyna,Liberek, Bogdan
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p. 3509 - 3518
(2007/10/02)
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