cas 962-39-0, benzyl 3-phenyl-L-alaninate | Articles data

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Synthesis, antitumor activity and in silico analyses of amino acid derivatives of artepillin C, drupanin and baccharin from green propolis
Breast cancer has the highest incidence and mortality in females, while prostate cancer has the second-highest incidence in males. Studies have shown that compounds from Brazilian green propolis have antitumor activities and can selectively inhibit the AKR1C3 enzyme, overexpressed in hormone-dependent prostate and breast tumors. Thus, in an attempt to develop new cytotoxic inhibitors against these cancers, three prenylated compounds, artepillin C, drupanin and baccharin, were isolated from green propolis to synthesize new derivatives via coupling reactions with different amino acids. All obtained derivatives were submitted to antiproliferative assays against four cancer cells (MCF-7, MDA MB-231, PC-3, and DU145) and two normal cell lines (MCF-10A and PNT-2) to evaluate their cytotoxicity. In general, the best activity was observed for compound 6e, derived from drupanin, which exhibited half-maximal inhibitory concentration (IC50) of 9.6 ± 3 μM and selectivity index (SI) of 5.5 against MCF-7 cells. In silico studies demonstrated that these derivatives present coherent docking interactions and binding modes against AKR1C3, which might represent a possible mechanism of inhibition in MCF-7 cells.
Rodrigues, Débora Munhoz,Portapilla, Gisele Bulh?es,Silva, Guilherme Martins,Duarte, Andressa,Rotta, Cristiana Gon?alez,da Silva, Carlos Henrique Tomich de Paula,de Albuquerque, Sérgio,Bastos, Jairo Kenupp,Campo, Vanessa Leiria
(2021/08/30)

Transition Metal-Free N-Arylation of Amino Acid Esters with Diaryliodonium Salts
A transition metal-free approach for the N-arylation of amino acid derivatives has been developed. Key to this method is the use of unsymmetric diaryliodonium salts with anisyl ligands, which proved important to obtain high chemoselectivity and yields. The scope includes the transfer of both electron deficient, electron rich and sterically hindered aryl groups with a variety of different functional groups. Furthermore, a cyclic diaryliodonium salt was successfully employed in the arylation. The N-arylated products were obtained with retained enantiomeric excess.
Kervefors, Gabriella,Kersting, Leonard,Olofsson, Berit
p. 5790 - 5795
(2021/03/08)

A novel route towards cycle-tail peptides using oxime resin: Teaching an old dog a new trick
Two anabaenopeptins, Schizopeptin 791 and anabaenopeptin NZ825, have similar structural features and have been synthesized via a novel acid-catalyzed head-to-side-chain concomitant cyclization/cleavage reaction on oxime resin. The methodology gave rapid access to the anabaenopeptin scaffold by taking advantage of a combined solid-phase/solution-phase synthetic strategy. Also, as side-products of the synthesis, large C2-symmetric 38-member cyclic peptides ring bearing two endocyclic lysine side-chains were isolated, constituting a novel cyclic peptide scaffold.
Bérubé, Christopher,Borgia, Alexandre,Voyer, Normand
supporting information
p. 9117 - 9123
(2019/01/03)

Probe compounds for fluorescence recognition of amino acid enantiomers and synthesis and applications thereof
The invention provides probe compounds for fluorescence recognition of amino acid enantiomers. Probe compounds (a, b, c) are prepared by following steps: dissolving dimethyl squarate into anhydrous methanol, dropwise adding methanol solutions of phenylalanine ethyl ester, phenylalanine benzyl ester, and phenylalanine tert-butyl ester, after addition, stirring the solution for 20 to 24 hours at a room temperature, filtering the solution, and finally washing the filter residues by ethyl acetate several times. When D-proline is added into ethanol-water solutions of chiral probe compounds (a, c),the fluorescence strength of the solutions is reduced; when L-proline is added into the solutions, the fluorescence strength of the solutions is enhanced obviously; and thus the probe compounds (a,c)have a good recognition effect on two enantiomers of proline. When L-valine is added into ethanol-water solutions of the probe compound (b), the fluorescence strength of the solution is obviously reduced; when D-valine is added into the solution, the fluorescence strength of the solution is not changed; and thus the probe compound (b) has a good recognition effect on two enantiomers of valine.
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Paragraph 0030

(2019/01/05)

Synthesis of Tripeptide Derivatives with Three Stereogenic Centers and Chiral Recognition Probed by Tetraaza Macrocyclic Chiral Solvating Agents Derived from d -Phenylalanine and (1 S,2 S)-(+)-1,2-Diaminocyclohexane via 1H NMR Spectroscopy
Enantiomers of a series of tripeptide derivatives with three stereogenic centers (±)-G1-G9 have been prepared from d- and l-α-amino acids as guests for chiral recognition by 1H NMR spectroscopy. In the meantime, a family of tetraaza macrocyclic chiral solvating agents (TAMCSAs) 1a-1d has been synthesized from d-phenylalanine and (1S,2S)-(+)-1,2-diaminocyclohexane. Discrimination of enantiomers of (±)-G1-G9 was carried out in the presence of TAMCSAs 1a-1d by 1H NMR spectroscopy. The results indicate that enantiomers of (±)-G1-G9 can be effectively discriminated in the presence of TAMCSAs 1a-1d by 1H NMR signals of multiple protons exhibiting nonequivalent chemical shifts (ΔΔδ) up to 0.616 ppm. Furthermore, enantiomers of (±)-G1-G9 were easily assigned by comparing 1H NMR signals of the split corresponding protons with those attributed to a single enantiomer. Different optical purities (ee up to 90%) of G1 were clearly observed and calculated in the presence of TAMCSAs 1a-1d, respectively. Intermolecular hydrogen bonding interactions were demonstrated through theoretical calculations of enantiomers of (±)-G1 with TAMCSA 1a by means of the hybrid functional theory with the standard basis sets of 3-21G of the Gaussian 03 program.
Feng, Lei,Gao, Guangpeng,Zhao, Hongmei,Zheng, Li,Wang, Yu,Stavropoulos, Pericles,Ai, Lin,Zhang, Jiaxin
p. 13874 - 13887
(2018/11/23)

Method for preparing amino ether compounds
The invention belongs to the technical field of organic synthesis and relates to a method for preparing amino ether compounds. The method comprises the following steps: by taking amino alcohol as a raw material, protecting amino in the amino alcohol so as to obtain Schiff base; carrying out an etherification reaction on the hydroxyl group in the Schiff base; and finally, performing amino deprotection, thereby obtaining corresponding amino ethers. The method disclosed by the invention has high regio-selectivity, the substrates of higher than 99.9% are subjected to etherification reaction, the reaction conversion ratio of each step is higher than 99.8%, and the total yield is higher than 95%; when amino alcohol is chiral, the amino ethers with retention of configuration can be obtained; and moreover, each step of the method is a conventional operation, the process cost is low, and three wastes are few, the energy consumption is low, an environment-friendly effect is achieved, and large-scale industrial production is easily realized.
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Paragraph 0066; 0069; 0070

(2017/08/26)

O -Phthalaldehyde catalyzed hydrolysis of organophosphinic amides and other P(O)-NH containing compounds
Over 50 years ago, Jencks and Gilchrist showed that formaldehyde catalyses the hydrolysis of phosphoramidate through electrophilic activation, induced by covalent attachment to its nitrogen atom. Given our interest in the use of aldehydes as catalysts, this work was revisited to identify a superior catalyst, o-phthalaldehyde, which facilitates hydrolyses of various organophosphorus compounds bearing P(O)-NH subunits under mild conditions. Interestingly, chemoselective hydrolysis of the P(O)-N bonds could be accomplished in the presence of P(O)-OR bonds.
Li, Bin-Jie,Simard, Ryan D.,Beauchemin, André M.
supporting information
p. 8667 - 8670
(2017/08/10)

A protic ionic liquid catalyzed strategy for selective hydrolytic cleavage of tert-butyloxycarbonyl amine (N-Boc)
A simple, mild and efficient strategy for selective hydrolytic cleavage of the N-tert-butyloxycarbonyl (Boc) group is devised using a protic ionic liquid as an efficient catalyst. The deprotection reaction proceeded well for N-Boc protected aromatic, heteroaromatic, aliphatic compounds, and chiral amino acid esters and peptides. A wide range of labile protecting groups such as tert-butyl ester, tert-butyl ether, benzyloxycarbonyl (Cbz), TBDMS, O-Boc and S-Boc remained unaffected under the reaction conditions. This journal is
Majumdar, Swapan,De, Jhinuk,Chakraborty, Ankita,Roy, Dipanwita,Maiti, Dilip K.
p. 3200 - 3205
(2015/02/03)

Self-Assembly of Tetraphenylalanine Peptides
Three different tetraphenylalanine (FFFF) based peptides that differ at the N- and C-termini have been synthesized by using standard procedures to study their ability to form different nanoassemblies under a variety of conditions. The FFFF peptide assembles into nanotubes that show more structural imperfections at the surface than those formed by the diphenylalanine (FF) peptide under the same conditions. Periodic DFT calculations (M06L functional) were used to propose a model that consists of three FFFF molecules defining a ring through head-to-tail NH3+?-OOC interactions, which in turn stack to produce deformed channels with internal diameters between 12 and 16 ?. Depending on the experimental conditions used for the peptide incubation, N-fluorenylmethoxycarbonyl (Fmoc) protected FFFF self-assembles into a variety of polymorphs: ultra-thin nanoplates, fibrils, and star-like submicrometric aggregates. DFT calculations indicate that Fmoc-FFFF prefers a parallel rather than an antiparallel β-sheet assembly. Finally, coexisting multiple assemblies (up to three) were observed for Fmoc-FFFF-OBzl (OBzl = benzyl ester), which incorporates aromatic protecting groups at the two peptide terminals. This unusual and noticeable feature is attributed to the fact that the assemblies obtained by combining the Fmoc and OBzl groups contained in the peptide are isoenergetic. Variety show! Three different tetraphenylalanine-based peptides that differ at the N- and C-termini have been synthesized by using standard procedures to study their ability to form different nanoassemblies (e.g., nanotubes, see figure) under a variety of conditions.
Mayans, Enric,Ballano, Gema,Casanovas, Jordi,Díaz, Angélica,Pérez-Madrigal, Maria M.,Estrany, Francesc,Puiggalí, Jordi,Cativiela, Carlos,Alemán, Carlos
p. 16895 - 16905
(2015/11/16)

Enantiospecific C-H Activation Using Ruthenium Nanocatalysts
The activation of C-H bonds has revolutionized modern synthetic chemistry. However, no general strategy for enantiospecific C-H activation has been developed to date. We herein report an enantiospecific C-H activation reaction followed by deuterium incorporation at stereogenic centers. Mechanistic studies suggest that the selectivity for the α-position of the directing heteroatom results from a four-membered dimetallacycle as the key intermediate. This work paves the way to novel molecular chemistry on nanoparticles.
Taglang, Céline,Martínez-Prieto, Luis Miguel,Del Rosal, Iker,Maron, Laurent,Poteau, Romuald,Philippot, Karine,Chaudret, Bruno,Perato, Serge,Sam Lone, Ana?s,Puente, Céline,Dugave, Christophe,Rousseau, Bernard,Pieters, Grégory
supporting information
p. 10474 - 10477
(2015/09/02)

A practical aryl unit for azlactone dynamic kinetic resolution: Orthogonally protected products and a ligation-inspired coupling process
The first strategy for bringing about enantioselective azlactone dynamic kinetic resolution to generate orthogonally protected amino acids has been developed. In the presence of a C2-symmetric squaramide-based catalyst, benzyl alcohol reacts with novel yet readily prepared tetrachloroisopropoxycarbonyl-substituted azlactones to generate trapped phthalimide products of significant synthetic interest with excellent enantiocontrol. These materials are masked amino acids which are demonstrably orthogonally protected: cleavage of the phthalimide can be achieved in the presence of the ester and vice versa. This process could be utilized to bring about a highly stereoselective ligation-type coupling of protected serines (at stoichiometric loadings) with racemic azlactones derived from both natural and abiotic amino acids. After deprotection, a subsequent base-mediated Oa??N acyl transfer occurs to form a dipeptide.
Tallon, Sean,Manoni, Francesco,Connon, Stephen J.
p. 813 - 817
(2015/02/19)

Soluble non-cross-linked poly(norbornene) supports for peptide synthesis with minimal reagents
Solid-phase peptide synthesis has been an attractive method for synthesizing peptides because it is quick and can be automated. The heterogeneous reaction medium in solid-phase peptide synthesis necessitates the use of large equivalents of reagents to drive the reactions to completion. Peptide synthesis using soluble, yet isolable, supports is an attractive alternative to solid-phase peptide synthesis. Reported herein is a soluble poly(norbornene)-derived support containing multiple attachment sites for high loading capacities and solubilizing oligoether/alkyl groups. The Ala-attached support has been used to synthesize tri- to octapeptides in 28 to 97% yields using only 1.2 equiv of amino acids and coupling reagents. The acyclic hexapeptide precursor to natural product segatalin A was synthesized in 41% yield on the support using one-eighth of the equivalents of coupling reagents compared to that in reported procedures. The support could be recovered in up to 98% yield after peptide synthesis, and the recovered support was utilized to synthesize tri- and tetrapeptides that contain amino acids other than Ala at the C-terminus in ca. 80% yields.
Naganna, Nimmashetti,Madhavan, Nandita
p. 11549 - 11557
(2015/02/19)

Unusual reactivity of nitronates with an aryl alkyl carbonate: Synthesis of α-amino esters
The monoanions of nitroalkanes are ambident nucleophiles that react with carbonate electrophiles through the oxygen atom. Products arising from reactivity at the carbon atom will yield α-nitro esters, which are precursors for α-amino esters. We demonstrate this in the reactions of nitroalkanes with benzyl phenyl carbonate and DABCO where α-nitro esters are obtained instead of nitrile oxides. The products are readily reduced to α-amino esters. This pathway could be a safe alternative to the Strecker reaction.
Reddy, Golipalli Ramana,Mukherjee, Debopreeti,Chittoory, Arjun Kumar,Rajaram, Sridhar
p. 5874 - 5877
(2015/01/08)

Competing benzyl cation transfers in the gas-phase fragmentation of the protonated benzyl phenylalaninates
In this study, the competing benzyl cation transfer reactions have been explored by investigating the gas phase chemistry of the protonated benzyl phenylalaninates. Protonation at the carboxylic O atom results in the breakage of the ester CO bond to afford the benzyl cation, which undergoes the competing migration to the amino N atom or the phenyl ring C atom. Both the amino and the phenyl ring hydrogen atoms can be activated to be mobile due to the electrophilic attack of the transferring benzyl cation, and migration of the activated hydrogen atom to the carboxylic hydroxyl leads to (H2O + CO) elimination of the precursor ion. Interestingly, it is much more preferred for the benzyl cation to transfer to the phenyl ring via the amino N, leading to the stepwise benzyl cation transfer, albeit the amino N atom contains more nucleophilic affinity. The mechanistic processes have been confirmed by the MS3 spectra data, along with D-labeling experiments and theoretical calculations.
Li, Fei,Wu, Yanqing,Zhang, Ningwen,Jiang, Jianxiong,Jiang, Kezhi
p. 23 - 29
(2014/06/24)

Concise synthesis of α-methylene-β-hydroxy-γ-carboxy- γ-lactams
A concise protocol for the synthesis of α-methylene-β-hydroxy- γ-carboxy-γ-lactams has been described via alkylation of amino acid derived iminoesters with α-bromomethylmethacrylate, followed by allylic hydroxylation. All the synthesized compounds have been evaluated for their cytotoxicity on multiple myeloma cancer cell lines.
Tekkam, Srinivas,Johnson, Joseph L.,Jonnalagadda, Subash C.,Mereddy, Venkatram R.
p. 955 - 958
(2013/08/23)

An efficient synthesis of [2.2.1] heterobicyclic pyroglutamates
A novel methodology for the efficient synthesis of [2.2.1] heterobicyclic pyroglutamates has been described. The key synthetic steps involve alkylation of amino acid-derived iminoesters with Baylis-Hillman bromide, RhCl 3-catalyzed exocyclic olefin isomerization, diastereoselective dihydroxylation, and regioselective lactonization. All the compounds were evaluated for their cytotoxicity using multiple myeloma cancer cell lines RPMI 8226.
Tekkam, Srinivas,Johnson, Joseph L.,Jonnalagadda, Subash C.,Mereddy, Venkatram R.
p. 969 - 972
(2013/08/23)

Enantioselective synthesis of 1,2,4-triazolines by chiral iron(ii)-complex catalyzed cyclization of α-isocyano esters and azodicarboxylates
Enantioselective cyclization of α-isocyano esters with azodicarboxylates catalyzed by FeII-N,N′-dioxide complexes has been developed. Under mild conditions, a variety of 1,2,4-triazoline derivatives was obtained in high yields and enantioselectivities.
Wang, Min,Liu, Xiaohua,He, Peng,Lin, Lili,Feng, Xiaoming
supporting information
p. 2572 - 2574
(2013/04/10)

A multicatalyst system for the one-pot desymmetrization/oxidation of meso-1,2-alkane diols
Two is better than one: We demonstrate the viability of an organocatalytic reaction sequence along a short peptide backbone that carries two independent catalytic functionalities, which allow the rapid, one-pot acylative desymmetrization and oxidation of meso-alkane-1,2-diols to the corresponding acetylated acetoins with good yields and enantioselectivities (see scheme). Copyright
Mueller, Christian E.,Hrdina, Radim,Wende, Raffael C.,Schreiner, Peter R.
supporting information; experimental part
p. 6309 - 6314
(2011/08/07)

PHOTODISSOCIABLE PROTECTIVE GROUP
The present invention provides a photolabile protecting group that can be removed by light irradiation under mild conditions. More specifically, the present invention provides a method comprising protecting a reactive functional group (e.g., a hydroxyl group, amino group, carboxyl group, carbonyl group, phosphodiester group, etc.) by the photolabile protecting group, and then removing the photolabile protecting group simply by light irradiation under neutral conditions. The present invention relates to a compound represented by Formula (3): wherein Ar1 is an optionally substituted aromatic or heteroaromatic ring, Ar2 is an optionally substituted aryl or heteroaryl group, X is a leaving group, and n is an integer of 1 or 2; and a method of protecting and deprotecting an amino group etc. using the compound.
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Page/Page column 28-29

(2011/02/25)

A class of novel conjugates of substituted purine and Gly-AA-OBzl: Synthesis and evaluation of orally analgesic activity
Aimed at the chemotherapy of chronic pain two kinds of analgesic pharmacophores, substituted purine and Gly-AA-OBzl, were coupled via a five-step-reaction procedure and 19 novel conjugates N-[2-chloro-9- (tetrahydropyran-2-yl)-9H-purin-6-yl]-N-cyclopropylglycylamino acid benzylesters were provided. On mouse-tail flick model their in vivo analgesic activities were assayed. The results indicate that introducing Gly-OC2H 5 into the 6-position of the substituted purine leads to ambiguous increase of the analgesic activity, while introducing Gly-AA-OBzl into this position leads to significant increase of the analgesic activity.
Kang, Guifeng,Zhao, Ming,Zhang, Xiaoyi,Peng, Li,Li, Chunbo,Mao, Wei,Ye, Weidong,Peng, Shiqi
supporting information; experimental part
p. 6157 - 6160
(2010/12/19)

Synthesis and RNase A inhibition study of C2-symmetric bis-isochromenyl sulfones
A new class of C2-symmetric bis-isochromene derivatives with 3,3′-linkage has been synthesized from bis-propargyl sulfones. The method involves treatment of the sulfones with triethylamine to form the isochromene derivatives presumably via the intramolecular Michael addition to the intermediate bis-allenic sulfones. Interestingly, the product expected from the Garratt-Braverman pathway was not obtained. The bis-isochromene 7d displayed RNase A inhibition activity, much stronger than the isochromene 8 and bis-isocoumarin 9.
Mitra, Tapobrata,Dutta, Sansa,Basak, Amit
supporting information; experimental part
p. 2828 - 2831
(2010/07/06)

Esterification of unprotected a-Amino acids in ionic liquids as the reaction media
Ionic liquid 1,3-dimethylimidazolium methanesulfonate was used to prepare a-amino acids benzylic esters from unprotected amino acids and benzyl chloride. Esterification of several amino acids was achieved with satisfactory yields: by-products can be removed by a simple work-up procedure to afford the pure product. The described method is simple, mild, rapid and save.
Biondini, Daniele,Brinchi, Lucia,Germani, Raimondo,Goracci, Laura,Savelli, Gianfranco
experimental part
p. 39 - 44
(2010/08/22)

PREPARATIONS CONTAINING AMINO ACIDS AND OROTIC ACID
The present invention describes compounds produced from an orotic acid molecule and an ammo acid molecule The compounds, which include an amide linkage, are represented by the general Formula (I), wherein R is selected from the group consisting of (CH3)2CHCH2-, (CH3)2CH-, CH3CH2CH(CH3)-, H2NC(=NH)NH(CH2)3-, and C6H5CH2- Formula (I). The compounds are produced by one of two disclosed methods 1) reacting orotic acid or derivatives thereof with a thionyl halide, and then combining the acyl halide with an ammo acid in the presence of dichloromethane and a dimethylammopyπdme (DMAP) catalyst, or 2) protecting the carboxylic acid of an ammo acid with a benzyl group, and then combining the benzyl-protected ammo acid with a dicyclohexylcarbodiimide (DCC) activated orotic acid, followed by removal of the protecting group. The resulting ammo acid orotate amide compounds are aimed at providing enhanced stability in solution compared with the related esters.
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Page/Page column 14-15

(2009/07/18)

Study on synthesis, characteristics and catalysis properties of novel chiral metal complexes catalysts for 1,3-dipolar cycloaddition reactions of nitrone with electron-rich alkene
As a new class of potential catalysts for 1,3-dipolar cycloaddition reactions, fourteen L-amino acid Schiff base Cu(II) and Ti(IV) complexes were synthesized, characterized, and evaluated for their catalytic activities in the reaction between C, N-diphenylnitrone and electron-rich ethyl vinyl ether under both homogeneous and in situ conditions. The methods for preparation and utilization of the catalysts were elucidated in detail, and the results of the catalytic reactions were described and discussed as well. Excellent reaction results were found in the presence of some catalysts (20 mol%) with > 90% endo-isoazolidines produced, compared with predominantly exo-isoazolidine produced without a catalyst. In addition, the reaction rate is found to be enhanced remarkably by a Cu(II) complex Schiff base catalyst at room temperature.
You, Jun,Liu, Bo,Wang, Yi
experimental part
p. 1010 - 1017
(2010/08/13)

PREPARATIONS CONTAINING AMINO ACIDS AND OROTIC ACID
The present invention describes compounds produced from an orotic acid molecule and an amino acid molecule. The compounds being in the form of amino acid orotate compounds bound by an amide linkage and produced by one of two disclosed methods; 1) reacting orotic acid or derivatives thereof with a thionyl halide, and then combining the acyl halide with an amino acid in the presence of dichloromethane and a DMAP catalyst; or 2) protecting the carboxylic acid of an amino acid and then combining the amino acid with a DCC activated orotic acid, followed by removal of the carboxylic acid protecting group. The resulting amino acid orotate amide has an enhanced stability in solution as compared to a related ester. In addition, specific benefits are conferred by the particular amino acid used to form the compounds in addition to, and separate from, the orotate substituent.
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Page/Page column 6

(2009/07/03)

Potency and selectivity of P2/P3-modified inhibitors of cysteine proteases from trypanosomes
A systematic study of P2 and P3 substitution in a series of vinyl sulfone cysteine protease inhibitors is described. The introduction of a methyl substituent in the P2 phenylalanine aryl ring had a favorable effect on protease inhibition and conferred modest selectivity for rhodesain over cruzain. Rhodesain selectivity could be enhanced further by combining these P2 modifications with certain P3 amide substituents.
Jaishankar, Priyadarshini,Hansell, Elizabeth,Zhao, Dong-Mei,Doyle, Patricia S.,McKerrow, James H.,Renslo, Adam R.
p. 624 - 628
(2008/09/16)

Open-air and solvent-free ester condensation catalyzed by sulfonic acids
Ester condensation is one among the most fundamental organic transformations, and more environmentally benign alternatives to current esterification processes are needed. Under solvent-free and drying agent-free conditions, catalytic amounts of sulfonic acids promote ester condensation between an equimolar mixture of carboxylic acids and alcohols. In particular, p-toluenesulfonic acid (TsOH) and 10-camphorsulfonic acid (CSA), which have appropriate acidities, efficiently catalyze the ester condensation of secondary alcohols without their decomposition. Since the present protocol does not require solvents under simple open-air conditions, a large amount of esters can be synthesized in a rather small apparatus.
Sakakura, Akira,Koshikari, Yoshiki,Ishihara, Kazuaki
p. 5017 - 5020
(2008/12/21)

Dynamic Kinetic resolution of α-amino acid esters in the presence of aldehydes
A convenient procedure for the racemization of α-amino acid esters in the presence of catalytic amounts of salicylaldehydes is described. The combination of this racemization protocol with lipase-catalyzed ester hydrolysis allows successful dynamic kinetic resolution of various α-amino acid esters. The corresponding α-amino acids are obtained in high yield and optical purity. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
Schichl, Daniel A.,Enthaler, Stephan,Holla, Wolfgang,Riermeier, Thomas,Kragl, Udo,Beller, Matthias
scheme or table
p. 3506 - 3512
(2009/04/07)

A novel naphthylmethyleneimino-type photocleavable protecting group for primary amines
A novel naphthylmethyleneimino-type protecting group for aliphatic and aromatic primary amines including α-amino acids was devised and its introduction was accomplished in good to excellent yields. This type of protecting group was found to be cleanly removed photochemically to regenerate the primary amines in good to high yields, regardless of steric and electronic properties. Georg Thieme Verlag Stuttgart.
Igarashi, Tetsutaro,Shimokawa, Masaru,Iwasaki, Miyuki,Nagata, Kensaku,Fujii, Masato,Sakurai, Tadamitsu
p. 1436 - 1440
(2008/02/13)

PEPTIDIC COMPOUNDS
The present invention provides a compound of formula (I), (II), (III) and (IV) as defined herein and pharmaceutically acceptable derivatives thereof. The present invention further provides use of the compounds of the present invention in the treatment of bacterial infection and in the treatment of HIV infection. Also provided are pharmaceutical compositions comprising the compounds of the present invention.
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Page/Page column 79

(2008/06/13)

Dual-acting agents that possess free radical scavenging and antithrombotic activities: Design, synthesis, and evaluation of phenolic tetrahydro-β-carboline RGD peptide conjugates
A new approach to construct a single dual-acting agent is described. Compounds 6a-c are potent free radical scavengers as demonstrated by the EC50 values in PC12 cell survival assay in term of NO, H2O2, and {radical dot}OH scavenging activity. The Ach-induced vaso-relaxation assay further confirms the potent NO scavenging activity of compounds 6a-c. In addition, 6a-c are efficacious in a rat arterial thrombosis, and are active in ADP- or PAF-induced in vitro platelet aggregation assay, suggesting that compounds 6a-c also possess anti-thrombotic activities. Since both free radical and thrombogenesis are important risk factors in myocardial ischemic/reperfusion injuries, these dual-acting agents having both free radical scavenging and antithrombolic activities may potentially be beneficial toward their treatment.
Bi, Wei,Bi, Lanrong,Cai, Jianhui,Liu, Sanguang,Peng, Shiqi,Fischer, Nicholas O.,Tok, Jeffrey B.-H.,Wang, Guohua
p. 4523 - 4527
(2007/10/03)

Synthesis and cytotoxic activities of β-carboline amino acid ester conjugates
β-Carboline represents a class of compounds with potent anti-tumor activity by intercalating with DNA. To further enhance the cytotoxic potency and bioavailability of β-carboline, a series of novel β-carboline amino acid ester conjugates were designed and synthesized, and the cytotoxic activities of these compounds were tested using a panel of human tumor cell lines. In addition, the membrane permeability of these compounds was evaluated in vitro using a Caco-2 cell monolayer model. The β-carboline amino acid ester conjugates demonstrated improved cytotoxic activity compared to the parental β-carbolines. In particular, the Lys/Arg conjugates were the most potent analogs with an IC50 value of 4 and 1 μM against human cervical carcinoma cells. The low interaction energy of Arg conjugate based on molecular modeling may contribute to its enhanced cytotoxicity. Taken together, this study provided new insights into structure-activity relationships in the β-carboline amino acid ester conjugates and identified the β-carboline Lys/Arg conjugates as promising lead compounds for further in vivo biological and molecular evaluation.
Zhao, Ming,Bi, Lanrong,Wang, Wei,Wang, Chao,Baudy-Floc'h, Michele,Ju, Jingfang,Peng, Shiqi
p. 6998 - 7010
(2007/10/03)

Methods and compositions for treating amyloid-related diseases
Methods, compounds, pharmaceutical compositions and kits are described for treating or preventing amyloid-related disease.
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Page/Page column 133-134

(2010/11/24)

Total synthesis of cyclic tetrapeptide FR235222, a potent immunosuppressant that inhibits mammalian histone deacetylases
(Chemical Equation Presented) The total synthesis of FR235222, a potent immunosuppressant with in vivo activities, has been achieved. The key steps include assembling its (2S,9R)-2-amino-9-hydroxy-8-oxodecanoic acid residue via an olefin cross-metathesis of a methyl (R)-lactate-derived homoallyl ketone with protected allyl amino acid and constructing its trans-(2R,4S)-4-methylproline unit from protected (R)-pyroglutamic acid in seven steps.
Xie, Weiqing,Zou, Bin,Pei, Duanqing,Ma, Dawei
p. 2775 - 2777
(2007/10/03)

Capillary electrophoretic separation of enantiomers of amino acids and amino acid derivatives using crown ether and cyclodextrin
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
p. 181 - 185
(2007/10/03)

Synthesis of p-tert-butylcalix[4]arene derivatives containing amino acid residues
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Alekseeva,Bacherikov,Gren'
p. 490 - 491
(2007/10/03)

Electrochemical removal of the picolinoyl group under mild acidic conditions, application to the protection of amines in peptide synthesis
The picolinoyl group can be used as a convenient protective group for amines in peptide chemistry. Deprotection is performed by electrochemical reduction under mild acidic conditions.
Auzeil, Nicolas,Dutruc-Rosset, Gilles,Largeron, Martine
p. 2283 - 2286
(2007/10/03)

Bioactive Surfactants containing a &β-Lactam Group: Synthesis and Properties
Selective activation of 3-hydroxy-2-hydroxymethyl-2-methylpropanamide with P(NMe2)3-CCl4, and subsequent intramolecular cyclisation yields β-lactam derivatives that have both surface and antibiotic activity.
Molina, Laurence,Perani, Angelo,Infante, Maria-Rosa,Manresa, Maria-Angeles,Maugras, Michel,et al.
p. 1279 - 1280
(2007/10/02)

Application of a unique automated synthesis system for solution-phase peptide synthesis
An automated synthesis system, which is suitable for repetitive syntheses using similar reaction procedures, was used to synthesize systematically a library of all possible dipeptides (25) and tripeptides (125) from 5 protected amino acids. The apparatus has also been applied to the automated synthesis of 10 fragment tripeptide derivatives that are constituents of the hormone PACAP-27. The measured molecular optical rotation values of the library of 125 tripeptides were found to correlate well with calculated values obtained by summation of the molecular optical rotation values for the constituent amino acids.
Sugawara,Kobayashi,Okamoto,Kitada,Fujino
p. 1272 - 1280
(2007/10/02)

FUSED TRICYCLIC COMPOUNDS, PHARMACEUTICAL COMPOSITIONS CONTAINING THEM AND THEIR USE IN THERAPY
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(2008/06/13)

Synthesis and spectroscopic properties of azaglutamine amino acid and peptide derivatives
tert-Butyl carbazate and Boc-amino acid hydrazides undergo a Michael addition with acrylamide to give substituted carbazates having the side-chain of glutamine on nitrogen. These carbazates may react with chloroformates to give protected azaglutamine esters, and N-activated amino acid esters to give azaglutamine peptides.
Gray,Quibell,Jiang,Baggett
p. 141 - 146
(2007/10/02)

PALLADIUM-CATALYZED REACTION OF TRIBUTYLTIN HYDRIDE. SELECTIVE AND VERY MILD DEPROTECTION OF ALLYL AND ALLYLOXYCARBONYL DERIVATIVES OF AMINO-ACIDS.
Allyl(All) and Allyloxycarbonyl(Alloc) amino-acid derivatives are deprotected through palladium-catalyzed hydrostannolysis by Bu3SnH in a highly selective manner.Benzyl and benzyloxycarbonyl groups are stable under these conditions.Moreover the allyl and Alloc groups seem orthogonal to the t-butyl and t-butoxycarbonyl protecting groups.
Guibe, F.,Dangles, O.,Balavoine, G.
p. 2365 - 2368
(2007/10/02)