- Further hit optimization of 6-(trifluoromethyl)pyrimidin-2-amine based TLR8 modulators: Synthesis, biological evaluation and structure–activity relationships
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Toll-like receptor 8 (TLR8) is an endosomal TLR that has an important role in the innate human immune system, which is involved in numerous pathological conditions. Excessive activation of TLR8 can lead to inflammatory and autoimmune diseases, which highlights the need for development of TLR8 modulators. However, only a few small-molecule modulators that selectively target TLR8 have been developed. Here, we report the synthesis and systematic investigation of the structure–activity relationships of a series of novel TLR8 negative modulators based on previously reported 6-(trifluoromethyl)pyrimidin-2-amine derivatives. Four compounds showed low-micromolar concentration-dependent inhibition of TLR8-mediated signaling in HEK293 cells. These data confirm that the 6-trifluoromethyl group and two other substituents on positions 2 and 4 are important structural elements of pyrimidine-based TLR8 modulators. Substitution of the main scaffold at position 2 with a methylsulfonyl group or para hydroxy/hydroxymethyl substituted benzylamine is essential for potent negative modulation of TLR8. Our best-in-class TLR8-selective modulator 53 with IC50 value of 6.2 μM represents a promising small-molecule chemical probe for further optimization to a lead compound with potent immunomodulatory properties.
- Dol?ak, Ana,?ribar, Dora,Scheffler, Alexander,Grabowski, Maria,?vajger, Urban,Gobec, Stanislav,Holze, Janine,Weindl, Günther,Wolber, Gerhard,Sova, Matej
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- Highly Stable Zr(IV)-Based Metal-Organic Frameworks for Chiral Separation in Reversed-Phase Liquid Chromatography
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Separation of racemic mixtures is of great importance and interest in chemistry and pharmacology. Porous materials including metal-organic frameworks (MOFs) have been widely explored as chiral stationary phases (CSPs) in chiral resolution. However, it remains a challenge to develop new CSPs for reversed-phase high-performance liquid chromatography (RP-HPLC), which is the most popular chromatographic mode and accounts for over 90% of all separations. Here we demonstrated for the first time that highly stable Zr-based MOFs can be efficient CSPs for RP-HPLC. By elaborately designing and synthesizing three tetracarboxylate ligands of enantiopure 1,1′-biphenyl-20-crown-6, we prepared three chiral porous Zr(IV)-MOFs with the framework formula [Zr6O4(OH)8(H2O)4(L)2]. They share the same flu topological structure but channels of different sizes and display excellent tolerance to water, acid, and base. Chiral crown ether moieties are periodically aligned within the framework channels, allowing for stereoselective recognition of guest molecules via supramolecular interactions. Under acidic aqueous eluent conditions, the Zr-MOF-packed HPLC columns provide high resolution, selectivity, and durability for the separation of a variety of model racemates, including unprotected and protected amino acids and N-containing drugs, which are comparable to or even superior to several commercial chiral columns for HPLC separation. DFT calculations suggest that the Zr-MOF provides a confined microenvironment for chiral crown ethers that dictates the separation selectivity.
- Jiang, Hong,Yang, Kuiwei,Zhao, Xiangxiang,Zhang, Wenqiang,Liu, Yan,Jiang, Jianwen,Cui, Yong
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supporting information
p. 390 - 398
(2021/01/13)
-
- Structure-Elucidating Total Synthesis of the (Polyenoyl)tetramic Acid Militarinone C §
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The (polyenoyl)tetramic acid militarinone C (1) heads a family of seven members. Before our work, the configuration of C-5 was unknown whereas the configurations of C-8′ and C-10′ were either (R,R) or (S,S). We synthesized the four stereoisomers of constitution 1, which conform with these insights. This included cross-coupling both enantiomers of the western building block (8) with both enantiomers of the eastern building block (9). The specific rotations of the resulting 1 isomers suggested that natural 1 is configured like the coupling partners (S)-8 and (R,R)-9. This conclusion was corroborated by degrading natural 1 to alcohol 35 and by proving its configurational identity with synthetic (R,R)-35.
- Brückner, Reinhard,Drescher, Christian,Hamburger, Matthias,Keller, Morris,Potterat, Olivier
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supporting information
(2020/03/30)
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- CYCLIC PEPTIDES AS C5 A RECEPTOR ANTAGONISTS
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The invention relates to cyclic peptide derivatives, to their use in medicine, to compositions containing them, to processes for their preparation and to intermediates used in such processes. More particularly the invention relates to cyclic peptide C5a receptor antagonists of formula (Ia)or formula (Ib), or pharmaceutically acceptable salts thereof,wherein R1a, R1b, R2, R3 and R4 areas defined in the description. C5a receptor antagonists are potentially useful in the treatment of a wide range of 1 disorders,including inflammatory disorders and immune disorders.
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Page/Page column 65; 66
(2018/02/28)
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- Synthesis and Biological Evaluation of Modified Miuraenamides
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Miuraenamides, secondary metabolites of the marine myxobacterium Paraliomyxa miuraensis do not only show a high structural similarity to other cyclodepsipeptides isolated from sponges or terrestrial myxobacteria but they also exhibit a similar mode of act
- Kappler, Sarah,Karmann, Lisa,Prudel, Cynthia,Herrmann, Jennifer,Caddeu, Giulia,Müller, Rolf,Vollmar, Angelika M.,Zahler, Stefan,Kazmaier, Uli
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p. 6952 - 6965
(2018/11/25)
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- Exciton-Coupled Circular Dichroism Characterization of Monotopically Binding Guests in Host?Guest Complexes with a Bis(zinc porphyrin) Tweezer
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A stiff-stilbene-linked bisporphyrin tweezer with inherent helicity was used for exciton-coupled circular dichroism (ECCD) characterization of a series of monotopically binding amine guest molecules. CD signals were observed for a variety of monoamines at relatively low tweezer/amine (host/guest) ratios between 1 : 10 to 1 : 70. For the amines producing the most intense CD signals, a binding stoichiometry of 1 : 2 was found. A likely explanation is the presence of guest-guest interactions in the complexes. This is supported by the correlation observed between CD signal intensity and magnitude of possible noncovalent binding between the guests, which can be divided into three groups showing no, moderate and strong response, respectively. Further support for this rationalization comes from molecular modelling.
- Olsson, Sandra,Sch?fer, Clara,Blom, Magnus,Gogoll, Adolf
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p. 1169 - 1178
(2019/01/04)
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- A dinuclear biomimetic Cu complex derived from l-histidine: synthesis and stereoselective oxidations
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A dinuclear copper(ii) complex derived from the chiral N6 ligand (2S,2′S)-N,N′-(ethane-1,2-diyl)bis(2-((1-methyl-1H-imidazol-4-ylmethyl)-amino)-3-(1-trityl-1H-imidazol-4-yl)propanamide) (EHI) was synthesized and studied as a catalyst in stereoselective oxidation reactions. The ligand contains two sets of tridentate binding units, each of them giving rise to a coordination set consisting of a pair of 5- and 6-membered chelate rings, connected by an ethanediamide linker. Stereoselectivity effects were studied in the oxidations of a series of chiral l/d biogenic catechols and the pair of l/d-tyrosine methyl esters, in this case as their phenolate salts. The oxidation of β-naphthol has also been studied as a model monooxygenase reaction. The catechol oxidation was investigated in a range of substrate concentrations at slightly acidic pH and exhibited a marked dependence on the concentration of the [Cu2EHI]4+ complex. This behavior has been interpreted in terms of an equilibrium between a monomeric and a dimeric form of the catalyst. Binding studies of l- and d-tyrosine were performed as a support for the interpretation of the stereoselectivity effects observed in the reactions. In general, [Cu2EHI]4+ exhibits a binding preference for the l- rather than the d-enantiomer of the substrates, but it appears that in the catecholase reaction the oxidation of the d-isomer occurs at a faster rate than for the l counterpart. The same type of enantio-discriminating behavior is observed in the oxidation of l-/d-tyrosine methyl esters. In this case the reaction produces a complex mixture of products; the main product consisting of a trimeric compound, likely formed by radical coupling reactions, has been isolated and characterized. The oxidation of β-naphthol yields an additional product of the expected quinone but labeling experiments with 18-O2 show no oxygen incorporation into the product, confirming that the oxidation likely proceeds through a radical mechanism.
- Perrone, Maria L.,Salvadeo, Elena,Lo Presti, Eliana,Pasotti, Luca,Monzani, Enrico,Santagostini, Laura,Casella, Luigi
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p. 4018 - 4029
(2017/03/31)
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- Method for synthesizing tyrosine framework type periodic mesoporous organosilicas materials
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The invention relates to a method for preparing tyrosine framework type periodic mesoporous organosilicas materials. The method for synthesizing the tyrosine framework type periodic mesoporous organosilicas materials includes esterifying tyrosine in methanol by the aid of thionyl chloride; carrying out acrylation on the tyrosine by the aid of hydrazine hydrate and carrying out reaction on the tyrosine and isocyanic acid propyltriethoxysilane to obtain tyrosine organosilicas precursors; hydrolyzing the tyrosine organosilicas precursors and surfactants under acidic conditions to form PMO (periodic mesoporous organosilicas) materials; removing the surfactants from the PMO materials by means of extraction to ultimately form PMO materials with specific morphological structures. The tyrosine is used as a substrate. The methanol is used as a solvent. The method has the advantages synthesis reaction raw materials are simple and are easily available, synthesis operation is simple and convenient and is easy to implement, and the method is high in yield and low in energy consumption and is safe and inexpensive; the tyrosine framework type periodic mesoporous organosilicas materials prepared by the aid of the method have important application prospects in the fields of biosensors, catalyst carriers, adsorbents, sustained-release medicine capsules, chromatographic separation and the like.
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Paragraph 0024
(2017/08/29)
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- BISAMIDE COMPOUNDS AS ALLOSTERIC EFFECTORS FOR REDUCING THE OXYGEN-BINDING AFFINITY OF HEMOGLOBIN
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This invention relates to compounds of Formula (I) and pharmaceutically acceptable salts thereof, which are allosteric effectors that reduce the oxygen-binding affinity of hemoglobin, which can enhance the efficacy of radiation therapy for cancer and which are useful for the treatment of ischemia and other conditions.
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-
Paragraph 0239-0240
(2016/12/01)
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- BISAMIDE COMPOUNDS AS ALLOSTERIC EFFECTORS FOR REDUCING THE OXYGEN-BINDING AFFINITY OF HEMOGLOBIN
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This invention relates to compounds of Formula (I) and pharmaceutically acceptable salts thereof, which are allosteric effectors that reduce the oxygen-binding affinity of hemoglobin, which can enhance the efficacy of radiation therapy for cancer and which are useful for the treatment of ischemia and other conditions.
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Page/Page column 43
(2015/07/23)
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- Palladium-catalyzed oxalyl amide assisted direct ortho-alkynylation of arylalkylamine derivatives at δ and ε positions
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Palladium-catalyzed oxalyl amide directed ortho-alkynylation of arylalkylamine derivatives is reported for the first time. A wide variety of β-arylethamine and γ-arylpropamine derivatives are compatible with this protocol. This method provides a general means to synthesize substituted alkynylarylalkylamine derivatives, highlighting the ability of oxalyl amide in promoting C-H functionalization at unique δ and ε positions.
- Guan, Mingyu,Chen, Changpeng,Zhang, Jingyu,Zeng, Runsheng,Zhao, Yingsheng
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supporting information
p. 12103 - 12106
(2015/07/28)
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- Synthesis of d,l-amino acid derivatives bearing a thiol at the β-position and their enzymatic optical resolution
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Amino acids bearing a thiol group at the β-position are useful for native chemical ligation. Phenylalanine and tyrosine derivatives bearing a thiol group at the β-position were synthesized. Racemic phenylalanine and tyrosine were selected as starting materials and were introduced a bromo atom at the β-position by photoreaction. Subsequent substitution reaction of the bromo atom with p-methoxybenzylmercaptan yielded the corresponding amino acids bearing a thiol group at the β-position. Enzymatic optical resolution using l-aminoacylase and subsequent chemical conversion gave the corresponding optically pure l- and d-phenylalanine and tyrosine derivatives bearing a thiol group at the β-position.
- Morishita, Yasuhito,Kaino, Tomoka,Okamoto, Ryo,Izumi, Masayuki,Kajihara, Yasuhiro
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p. 6565 - 6568
(2015/11/09)
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- A small molecule peptidomimetic of spider silk and webs
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A peptidomimetic compound containing leucine, tyrosine and malonic acid self-assembles through various noncovalent interactions to form spider silk-like fibers at ambient temperature. From the high-density liquid, a liquid-solid phase transition is initiated at 20 °C and solidification occurs upon contact with air. The fiber has comprehensive mechanical strength and optical properties similar to spider silk, and can be used to mimic a natural spider web. This journal is
- Maji, Krishnendu,Sarkar, Rajib,Bera, Santu,Haldar, Debasish
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supporting information
p. 12749 - 12752
(2015/05/20)
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- Enzyme kinetic studies of histone demethylases KDM4C and KDM6A: Towards understanding selectivity of inhibitors targeting oncogenic histone demethylases
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To investigate ligand selectivity between the oncogenic KDM4C and tumor repressor protein KDM6A histone demethylases, KDM4C and KDM6A were enzymatically characterized, and subsequently, four compounds were tested for inhibitory effects. 2,4-dicarboxypyrid
- Kristensen, Jan B.L.,Nielsen, Anders L.,Jorgensen, Lars,Kristensen, Line H.,Helgstrand, Charlotte,Juknaite, Lina,Kristensen, Jesper L.,Kastrup, Jette S.,Clausen, Rasmus P.,Olsen, Lars,Gajhede, Michael
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scheme or table
p. 1951 - 1956
(2012/06/15)
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- Oxidation of oximes to nitrile oxides with hypervalent iodine reagents
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Iodobenzene diacetate in MeOH containing a catalytic amount of TFA efficiently oxidizes aldoximes to nitrile oxides. The latter may be trapped in situ with olefins in a bimolecular or an intramolecular mode. The new method enables the execution of tandem oxidative dearomatization of phenols/intramolecular nitrile oxide cycloaddition sequences leading to useful synthetic intermediates.
- Mendelsohn, Brian A.,Lee, Shelley,Kim, Simon,Teyssier, Florian,Aulakh, Virender S.,Ciufolini, Marco A.
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supporting information; experimental part
p. 1539 - 1542
(2009/08/07)
-
- Synthesis and structure revision of tyroscherin, a growth inhibitor of IGF-1-dependent tumor cells
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Synthesis of the proposed structure of tyroscherin, a growth inhibitor of IGF-1-dependent cancer cells, was succeeded by one-pot Julia coupling. However, spectral data of the synthetic compound were not identical with those of natural tyroscherin. The stereochemistry of tyroscherin was revised to be 2S,3R,8R,10R by syntheses of stereoisomers.
- Katsuta, Ryo,Shibata, Chié,Ishigami, Ken,Watanabe, Hidenori,Kitahara, Takeshi
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body text
p. 7042 - 7045
(2009/04/14)
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- Head-to-tail interactions in tyrosine/benzophenone dyads in the ground and the excited state: NMR and laser flash photolysis studies
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The formation of head-to-tail contacts in de novo synthesized benzophenone/tyrosine dyads, bp∩Tyr, was probed in the ground and excited triplet state by NMR techniques and laser flash photolysis, respectively. The high affinity of triplet-excited ketones
- Hoerner, Gerald,Hug, Gordon L.,Pogocki, Dariusz,Filipiak, Piotr,Bauer, Walter,Grohmann, Andreas,Laemmermann, Anica,Pedzinski, Tomasz,Marciniak, Bronislaw
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supporting information; experimental part
p. 7913 - 7929
(2009/10/23)
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- Bis(diamido)-bridged basket resorcin[4]arenes as enantioselective receptors for amino acids and amines
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On the research avenue opened by the rigidified double-spanned resorcin[4]arene 1, we have synthesized both enantiomers of the two chiral basket resorcin[4]arenes 3 and 4, each containing two 1,2-diaminocyclohexane and 1,2-diphenylethylenediamine bridges, respectively. In the new compounds, the aromatic rims assume the expected flattened cone arrangement, whereas two different conformations, tentatively designated as "open wings" and "folded wings", were attributed to the bridge substituents according to molecular modeling studies. In MSn (ESI) experiments, the proton-bonded diastereomeric [4·H·A]+ complexes with amino acidic guests (A) exhibited a pronounced selectivity towards the enantiomers of tyrosine methyl ester (tyrOMe) and amphetamine (amph), whereas the chirality of tryptophan (trp) was ineffective. Moreover, a kinetic study on the base-induced displacement of the guest revealed that the L-tyr OMe (and L-amph) enantiomer is faster displaced from the heterochiral [4·H·L-tyrOMe]+ (or [ent- 4·H·L-amph]+) complex than from the homochiral [ent-4·H·L-tyrOMe]+ (or [4·H· L-amph]+) one. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Botta, Bruno,D'Acquarica, Ilaria,Nevola, Laura,Sacco, Fabiola,Lopez, Zara Valbuena,Zappia, Giovanni,Fraschetti, Caterina,Speranza, Maurizio,Tafi, Andrea,Caporuscio, Fabiana,Letzel, Matthias C.,Mattay, Jochen
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p. 5995 - 6002
(2008/09/17)
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- Design, synthesis, and bioactivity of novel inhibitors of E. coli aspartate transcarbamoylase
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A series of inhibitors of the aspartate transcarbamoylase, an enzyme involved in pyrimidine nucleotide biosynthesis, has been synthesized. These inhibitors are analogues of a highly potent inhibitor of this enzyme, N-phosphonacetyl-l-aspartate (PALA). Analogues have been synthesized with modifications at the α- and β-carboxylates as well as at the aspartate moiety. The ability of these compounds to inhibit the enzyme was evaluated. These studies, with functional group modified PALA derivatives, showed that amide groups can be a useful substitute of the carboxylate in order to reduce the charge on the molecule, and indicate that the relative position of the functional group in the β-position is more critical than the nature of the functional group. Some of the molecules synthesized here are potent inhibitors of the enzyme.
- Eldo, Joby,Heng, Sabrina,Kantrowitz, Evan R.
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p. 2086 - 2090
(2007/10/03)
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- Gas-phase enantioselectivity of chiral amido[4]resorcinarene receptors
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Diastereomeric proton-bound [1LHA]+ complexes between selected amino acids (A = phenylglycine (Phg), tryptophan (Trp), tyrosine methyl ester (TyrOMe), threonine (Thr), and allothreonine (AThr)) and a chiral amido[4]resorcinarene receptor (1L) display a significant enantioselectivity when undergoing loss of the amino acid guest A by way of the enantiomers of 2-aminobutanes (B) in the gas phase. The enantioselectivity of the B-to-A displacement is ascribed to a combination of thermodynamic and kinetic factors related to the structure and the stability of the diastereomeric [1LHA]+ complexes and of the reaction transition states. The results of the present and previous studies allow classification of the [1LHA]+ complexes in three main categories wherein: i) guest A does not present any additional functionalities besides the amino acid one (alanine (Ala), Phg, and phenylalanine (Phe)) ; ii) guest A presents an additional alcohol function (serine (Ser), Thr, and AThr); and iii) guest A contains several additional functionalities on its aromatic ring (tyrosine (Tyr), TyrOMe, Trp, and 3,4-dihydroxyphenylalanine (DOPA)). Each category exhibits a specific enantioselectivity depending upon the predominant [1 LHA]+ structures and the orientation of the 2-aminobutane reactant in the relevant adducts observed. The results may contribute to the understanding of the exceptional selectivity and catalytic properties of enzyme mimics towards unsolvated biomolecules.
- Botta, Bruno,Caporuscio, Fabiana,D'Acquarica, Ilaria,Delle Monache, Giuliano,Subissati, Deborah,Tafi, Andrea,Botta, Maurizio,Filippi, Antonello,Speranza, Maurizio
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p. 8096 - 8105
(2007/10/03)
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- INTERMEDIATE COMPOUND WHICH IS USED FOR THE PREPARATION OF PIOGLITAZONE
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The present invention relates to a novel compound of formula (IV) which is an intermediate that can be used for the preparation of pioglitazone. It also relates to a method of obtaining the novel compound (IV) starting from the natural product L-tyrosine, in which the amino group is protected in the form of aromatic imino group, and a method of obtaining pioglitazone from the said intermediate.
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- EXOGENOUS MARKERS FOR OXIDATIVE STRESS
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The invention provides oxogenous markers, designed and synthesized for the measurement and characterization of oxidative/nitrosative stress levels, thus enable the identification of the type of reactive ROS/NRS involved, characterization of the damaged products and their formation kinetics, and thereby the identification of pathological conditions associated with oxidative/nitrosative stress, before appearing or at the stage of development.
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Page/Page column 20-21
(2008/06/13)
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- Ligand creation via linking - A rapid and convenient method for construction of novel supported PyOX-ligands
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A novel supported amino alcohol linker was synthesized and utilized for attachment of picolinic acid derivatives onto different supports. When the resin bound molecule was further activated, the PyOX-moiety could be constructed reliably in enantiopure form. Furthermore, an efficient Pd-catalyzed modification of a picolinic acid derivative is presented.
- Oila, Markku J.,Tois, Jan E.,Koskinen, Ari M.P.
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p. 10748 - 10756
(2007/10/03)
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- Capillary electrophoretic separation of enantiomers of amino acids and amino acid derivatives using crown ether and cyclodextrin
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The capillary zone electrophoresis using (+)-18-crown-6-tetracarbonic acid as a chiral selector was a suitable method for the enantiomeric separation of racemates of amino acids and of some amino acid derivatives (esters, dipeptides). The influence of the chemical structure of the compounds on the separation was investigated. After optimization of the separation conditions, baseline separations were obtained for most racemates. The addition of acetonitrile and TBAB yielded an improvement of the separation. Improved selectivity was further observed by the application of a cyclodextrin, HP-β-CD, in combination with the crown ether.
- Salami,Jira,Otto, Hans-Hartwig
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p. 181 - 185
(2007/10/03)
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- Quantitative enzymatic protection of D-amino acid methyl esters by exploiting 'relaxed' enantioselectivity of penicillin-G amidase in organic solvent
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A quantitative method for enzymatic protection of esters of various d-amino acids in organic solvent is reported. The lower enantioselectivity displayed by penicillin-G amidase (PGA) from E. coli in organic solvent has been exploited for developing a facile, fast and quantitative method for protection of esters of various d-amino acids via N-acylation. The feasibility of the deprotection of the acylated products was also demonstrated by employing PGA from two different sources in aqueous media. Experimental results are in agreement with previous calculations based on in silico models of the enzyme active site.
- Carboni, Chiara,Quaedflieg, Peter J. L. M.,Broxterman, Quirinus B.,Linda, Paolo,Gardossi, Lucia
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p. 9649 - 9652
(2007/10/03)
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- Diastereoselective iodoamidation of 3-acetoxybut-1-Enylamines: Synthesis of 3-acetoxy-4-iodo-2-(p-methoxybenzyl)pyrrolidines
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3α-Acetoxy-4α-iodo-2α-(p-methoxybenzyl)pyrrolidine (2) and its enanti-omer (3) were synthesized via diastereoselective iodoamidation, starting from D- or L-tyrosine. The key step contains unfavorable 5-endo-trig cyclization and the diastereoselective addition of ethynylmagnesium bromide to aldehydes (9) by the chelation-controlled Cram cyclic model.
- Chang, Kyu-Tae,Jang, Ki Chang,Park, Ho-Yong,Kim, Young-Kook,Park, Ki Hun,Lee, Woo Song
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p. 1173 - 1179
(2007/10/03)
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- New 1,4-anthracene-9,10-dione derivatives as potential anticancer agents
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The amino-substituted anthracene-9,10-dione (9,10-anthraquinone) derivatives represent one of the most important classes of potential anticancer agents. To better understand the basic rules governing DNA sequence specificity, we have recently synthesized a new class of d- and l- aminoacyl-anthraquinone derivatives. We have tested these new compounds as cytotoxic agents, and we have correlated their activity with the configuration of the chiral aminoacyl moiety. Molecular modeling studies have been performed to compare the test drugs in terms of steric overlapping. (C) 2000 Elsevier Science S.A.
- Zagotto,Supino,Favini,Moro,Palumbo
-
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- Chemo-enzymatic synthesis of optically active amino acids and peptides
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The industrial alkaline protease, alcalase, is stable and active in a high concentration of organic solvents and useful as a biocatalyst for (i) diastereoselective hydrolysis of peptide esters and preparation of racemization-free peptides; (ii) selective incorporation of esters of D-amino acid into peptides in t-butanol via a selective hydrolysis of esters of D,L-amino acid, followed by using the unhydrolyzed D-esters as a nucleophile in a kinetically controlled peptide bond formation; (iii) resolution of esters of amino acid in 95% t-butanol/5% water, followed by saponification of the unreacted esters to offer both enantiomers with high yield and optical purity; (iv) completely resolve amino-acid esters with high yield and optical purity via in situ racemization of the unreacted antipode catalyzed by pyridoxal 5-phosphate; (v) cryobioorganic synthesis of peptides with increased yields 15%-40% of peptide bond formation by reaction at 5 °C instead of 25-30 °C of a kinetically controlled enzymatic reaction in alcohols.
- Chen, Shui-Tein,Wang, Kung-Tsung
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p. 301 - 311
(2007/10/03)
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- Studies on cyclodepsipeptides - Part II : The total synthesis of jaspamide and geodiamolide-D
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The total synthesis of cyclodepsipeptides jaspamide and geodiamolide D have been presented.
- Rama Rao,Gurjar, Mukund K.,Nallaganchu, Bhaskara Rao,Bhandari, Ashok
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p. 7085 - 7088
(2007/10/02)
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- Selectivity and Specificity in Substrate Binding to Proteases: Novel Hydrolytic Reactions Catalysed by α-Chymotrypsin Suspended in Organic Solvents with Low Water Content and Mediated by Ammonium Hydrogen Carbonate
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α-Chymotrypsin suspended in organic solvents with low water content catalysed hydrolytic reactions in the presence of ammonium hydrogen carbonate.Molecular modelling studies were carried out and structure-reactivity relationships were established by studying the hydrolysis of amino acid derivatives and analogues.The enzyme was found to be stereoselective with respect to the hydrolysis of L-amino acid derivatives, but no stereoselectivity was observed when α-hydroxy esters were used as substrates.A general procedure for the resolution of aromatic amino acid esters is given.The results are interpreted in terms of molecular modelling based on X-ray crystallographic data and literature data.
- Ricca, Jean-Marc,Crout, David H. G.
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p. 1225 - 1234
(2007/10/02)
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- CONFIGURATIONAL REQUIREMENTS OF AROMATIC AMINO ACID RESIDUES FOR THE ACTIVITY OF PRP-HEXAPEPTIDE
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The three analogues with D-amino acid substituents at position 1 and 5 of PRP-hexapeptide were synthesized and tested for its biological activity to check the influence of the spatial orientation of aromatic rings on the immune response.One of the analogs
- Kubik, Aleksandra,Szewczuk, Zbigniew,Siemion, Ignacy,Wieczorek, Zbigniew,Spiegel, Krystyna,et al.
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p. 2583 - 2590
(2007/10/02)
-
- Chirally Selective Hydrolysis of D,L-Amino Acid Esters by Alkaline Protease
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Alcalase selectively catalyses the hydrolysis of D,L-amino acid methyl and benzyl ester to provide L-amino acid and D-amino acid ester with high optical purity.
- Chen, Shui-Tein,Wang, Kung-Tsung,Wong, Chi-Huey
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p. 1514 - 1516
(2007/10/02)
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- Tumor-resolving and histolytic medicaments and their use
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Dehydrooligopeptides, some of which are known, demonstrate histolytic and tumor-resolving activity and may be used in medicaments causing the lysis of animal tissues and/or tumors in warm-blooded animals.
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- Octapeptides and methods for their production
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New octapeptides having the formula Prot Grp-R-Trp-Ser-Tyr-R2 -Leu-Arg-Pro-R3 ; salts thereof; wherein R is Gln, Gln (bzl), His (bzl), Ser (bzl), Pro, Leu, Tyr (bzl), Ile, Cys (bzl) or Phe, R2 is D-Phe, D-Ala, D-Leu, D-Trp, D-Tyr, D-Tyr (Me), D-Ser, D-Met, D-Arg, D-Val, D-His, D-Gln, D-Phs, D-Thr, D-Pro, D-Me5 Phe or D-Asn and R3 is NH2, NH(lower alkyl), N-(lower alkyl)2, NH-benzyl, NHCH2 CH2 N-(lower alkyl)2 or NH-CH2 CH2 SO2 NH-benzyl; methods for their production; certain peptide intermediates and their salts used in the production thereof; and the use of said octapeptides as luteinizing hormone releasing factor antagonists.
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- Radioimmunoassay agents
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Novel steroid derivatives containing a tyrosine ester amide group linked to an 11-hydroxysteroid alkylene dicarboxylic hemi-ester are described, suitable for iodination with radioactive iodine, useful in radioimmunoassay.
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