cas 5845-53-4, D-Leucine methyl ester hydrochloride

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Synthesis and host-guest studies of chiral N-linked peptidoresorc[4]arenes
(Figure Presented) Four cone resorc[4]arene octamethyl ethers (10, 11, ent-10, and ent-11) tetrafunctionalized at the feet with valyl-leucine [LL- (6); DD- (ent-6)] and leucyl-valine [LL- (9); DD- (ent-9)] methyl esters have been synthesized. These compounds, obtained by conjugation of macrocycle tetracarboxylic acid chlorides with the appropriate terminal amino groups of the above dipeptides, are N-linked peptidoresorc[4]arenes. We found that these macrocycles (M) are capable of recognizing the homologue dipeptides as guests (G), both in solution and in the gas phase, by forming relatively stable host-guest complexes ([M·G]), resistant to chromatographic purification but not to heating. Complexation phenomena between M and G in solution were investigated by NMR methods, including NMR DOSY experiments, for the detection of translational diffusion. Heteroassociation constants of 2030 and 186 M -1 were obtained by the Foster-Fyfe method for the complexes [10·6] and [10·ent-6], respectively, the latter being comparable to the self-association constant of dipeptide itself. Conversely, the structural features of the proton-bound complexes [M·H·Gn] + (n = 1, 2), generated in the gas phase by electrospray ionization mass spectrometry (ESI-MS), were investigated by collision-induced dissociation (CID) experiments. In both cases, the four N-linked peptidoresorc[4]arenes were shown to act as synthetic receptors and to recognize the homologue dipeptide by means of hydrogen bonds.
Botta, Bruno,D'Acquarica, Ilaria,Delle Monache, Giuliano,Subissati, Deborah,Uccello-Barretta, Gloria,Mastrini, Massimo,Nazzi, Samuele,Speranza, Maurizio
p. 9283 - 9290
(2007)
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Convenient method for the synthesis of some novel chiral methyl 2-(2-oxo-2H-benzo[e][1,3]oxazin-3(4H)-yl)propanoate derivatives and biological evaluation of their antioxidant, cytotoxic, and molecular docking properties
Ten chiral methyl 2-(2-oxo-2H-benzo[e][1,3]oxazin-3(4H)-yl)propanoate derivatives 6a-6j have been synthesized from optically pure amino methyl phenol 5 and 4-nitrophenyl chloroformate. These derivatives 6a-6j are characterized by 1H NMR, 13C NMR, FT-IR, and HRMS spectral techniques. Optical purity of these derivatives was confirmed by chiral HPLC method. Ten synthesized ester derivatives 6a-6j were screened for their in vitro antioxidant activity. Among the compounds 6b-d and 6h-j have exhibited comparable antioxidant activity with ascorbic acid as a standard. Compounds 6a and 6e-g have shown moderate antioxidant activity. Further, the in vitro cytotoxicity of these compounds were studied through MTT cell proliferation assay in addition the effect on LDH leakage and NO release. Among the derivatives, 6j showed extremely best activity and the IC50 value (12.54 ± 0.71 μM) is very close to doxorubicin (7.2 ± 0.58 μM) as a standard. Compounds 6b, 6h, and 6i showed better inhibition next to compound 6j on the viability of HepG2 cells with an IC50 value (μM) of 56.02 ± 1.4, 41.76 ± 0.58, and 38.17 ± 0.34, respectively. Also, molecular docking studies have been carried out with STAT-3 (PDB ID: 1BG1) and BCL-2 (PDB ID: 4AQ3) proteins against the four active compounds 6b, 6h, 6i, and 6j. The binding energies of the tested compounds were in the range of ?7.76 to ?8.41 kcal/mol, which is very close to doxorubicin (?8.53 kcal/mol) as a standard. These molecular docking results are in good agreement with the in vitro studies.
Matam, Sivakumar,Kaliyan, Prabakaran,Selvaraj, Loganathan,Muthu, Seenivasa Perumal,Lohanathan, Bharathi Priya,Viswanadhan, Vijaya Padma,Makala, Himesh,Venkatasubramanian, Ulaganathan
supporting information
p. 569 - 579
(2020/12/11)

Photochemical Deracemization at sp3-Hybridized Carbon Centers via a Reversible Hydrogen Atom Transfer
A photochemical deracemization of 5-substituted 3-phenylimidazolidine-2,4-diones (hydantoins) is reported (27 examples, 69%-quant., 80–99% ee). The reaction is catalyzed by a chiral diarylketone which displays a two-point hydrogen bonding site. Mechanistic evidence (DFT calculations, radical clock experiments, H/D labeling) suggests the reaction to occur by selective hydrogen atom transfer (HAT). Upon hydrogen binding, one substrate enantiomer displays the hydrogen atom at the stereogenic center to the photoexcited catalyst allowing for a HAT from the substrate and eventually for its conversion into the product enantiomer. The product enantiomer is not processed by the catalyst and is thus enriched in the photostationary state.
Bach, Thorsten,Breitenlechner, Stefan,Gro?kopf, Johannes,Plaza, Manuel,Seitz, Antonia,Storch, Golo
supporting information
p. 21241 - 21245
(2021/12/27)

N-1 BRANCHED ALKYL SUBSTITUTED IMIDAZO[4,5-C]QUINOLINE COMPOUNDS, COMPOSITIONS, AND METHODS
Imidazo[4,5-c]quinoline compounds having a substituent that is attached at the N-1 position by a branched group, single enantiomers of the compounds, pharmaceutical compositions containing the compounds, and methods of making the compounds are disclosed. Methods of use of the compounds as immune response modifiers, for inducing (or inhibiting) cytokine biosynthesis in humans and animals, and in the treatment of diseases including infectious and neoplastic diseases are also disclosed.
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Page/Page column 65

(2020/12/29)

Cocrystallization of Chiral N7,N16-bis (S-1-Phenylethyl)-1,4,10,13-Tetraoxo-7,16-Diazacyclooctadecane-7,16-Dicarboxamide with Hydrochlorides of Methyl Ethers of Leucine and Valine Enantiomers
An attempt to co-crystallize N7,N16-bis(S-1-phenylethyl)-1,4,10,13-tetraoxo-7,16-diazacyclooctadecane-7,16-dicarboxamide (1) with hydrochlorides of methyl ethers (HCMEs) of L- and D-valine and also L- and D-leucine results in separate crystallization of diazacrown-ether 1 (or its monohydrate 1·H2O) and HCMEs of respective α-amino acids. Crystal structures of D-leucine 1·H2O (1) and HCME (2) compounds, which were not described previously, are solved by single crystal X-ray diffraction.
Fonari,Pluzhnik-Gladyr,Kamalov,Kravtsov, V. Kh.
p. 143 - 150
(2019/04/30)

Rhodium-Catalyzed Enantioselective Synthesis of Oxazinones via an Asymmetric Ring Opening-Lactonization Cascade of Oxabicyclic Alkenes
The rhodium-catalyzed asymmetric ring opening reaction of oxabicyclic alkenes is shown to be an efficient method for synthesizing chiral heterocycles. We demonstrate that the pairwise combination of chiral catalyst with chiral amino-acid-derived pronucleophiles results in a stereodivergent synthesis of diastereomeric hydroxyesters. A favorable conformational preference induces the subsequent lactonization of one diastereomer leading to the highly enantioselective synthesis of oxazinones.
Yen, Andy,Pham, Anh Hoang,Larin, Egor M.,Lautens, Mark
supporting information
p. 7549 - 7553
(2019/10/02)

Synthesis of a novel category of pseudo-peptides using an Ugi three-component reaction of levulinic acid as bifunctional substrate, amines, and amino acid-based isocyanides
The synthesis of a novel category of pseudo-peptides via intramolecular Ugi reaction of levulinic acid (4-oxopentanoic acid), aromatic and aliphatic amines, and amino acid-based isocyanides is reported. Levulinic acid was applied as a bifunctional substrate containing both carbonyl and acid moieties suitable for the Ugi reaction. This article provides a facile and convenient one-pot procedure for the synthesis of peptide-like heterocyclic molecules containing 2-pyrrolidone (γ-lactam), amide and ester functional groups with good to excellent yields.
Khalesi, Maryam,Halimehjani, Azim Ziyaei,Martens, Jürgen
supporting information
p. 852 - 857
(2019/04/17)

N-Heterocyclic Carbene Iron(III) Porphyrin-Catalyzed Intramolecular C(sp3)–H Amination of Alkyl Azides
Metal-catalyzed intramolecular C?H amination of alkyl azides constitutes an appealing approach to alicyclic amines; challenges remain in broadening substrate scope, enhancing regioselectivity, and applying the method to natural product synthesis. Herein we report an iron(III) porphyrin bearing axial N-heterocyclic carbene ligands which catalyzes the intramolecular C(sp3)–H amination of a wide variety of alkyl azides under microwave-assisted and thermal conditions, resulting in selective amination of tertiary, benzylic, allylic, secondary, and primary C?H bonds with up to 95 % yield. 14 out of 17 substrates were cyclized selectively at C4 to give pyrrolidines. The regioselectivity at C4 or C5 could be tuned by modifying the reactivity of the C5–H bond. Mechanistic studies revealed a concerted or a fast re-bound mechanism for the amination reaction. The reaction has been applied to the syntheses of tropane, nicotine, cis-octahydroindole, and leelamine derivatives.
Shing, Ka-Pan,Liu, Yungen,Cao, Bei,Chang, Xiao-Yong,You, Tingjie,Che, Chi-Ming
supporting information
p. 11947 - 11951
(2018/09/11)

A valsartan synthesis method of alkylation impurity (by machine translation)
A valsartan synthesis method of alkylation impurities, is to L - valine that may exist in the impurity D - valine, alanine, leucine isoleucine amino acid as the raw material and the like, in thionyl chloride under the conditions of the esterification reaction with methanol, after the reaction by reducing pressure methanol, then with 2 - cyano - 4' - bromomethyl biphenyl in the reaction under alkaline conditions, after completion of the reaction, saturated salt water washing, adding hydrochloric acid to adjust the pH=1 - 2, the temperature of the crystallization, filtering to obtain the target product valsartan alkylation impurity. The present invention is to provide high-purity impurity, will its known impurity used for alkylation of valsartan in mass analysis, the position of the clear of impurities in the sample, the degree of impurity of the sample inspection, optimizes the analytical method, contribute to improving the quality of valsartan research, for the production of valsartan reducing impurity, improve the quality of the valsartan; at the same time, this invention has mild condition, the reaction yield is higher, convenient operation and the like. (by machine translation)
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Paragraph 0019-0020

(2018/10/19)

Synthesis and antiproteasomal activity of novel O-benzyl salicylamide-based inhibitors built from leucine and phenylalanine
Inhibition of protein degradation is one of strategies for suppression of uncontrolled proliferation of cancer cells. Proteolytic degradation in cells is mainly ensured by proteasome and its inhibition by bortezomib showed benefit in clinical use for the treatment of multiple myeloma. We report here the library of antiproteasomal O-benzyl salicylamides built from leucine and phenylalanine. Prepared compounds displayed antiproliferative activity on K562, CEM and U266 cancer cell lines, ranging from high micromolar to submicromolar GI50 values. The most potent compounds (series 4 and 6) were further assayed for their inhibition of chymotrypsin-like protease activity of the 26S proteasome in U266 cells. The majority of compounds inhibited the proteasome in mid-nanomolar concentrations (IC50 ranging from 57 to 197 nM) and it correlated with cellular potency. In a cell based assay involving green fluorescence protein (GFP) fused to a short degron that is rapidly degraded by a proteasome the compounds induced accumulation of GFP, visualised and quantified by live-cell imaging. Levels of polyubiquitinated proteins in U266 cells treated by compound 4m were also analyzed by immunoblotting, revealing a typical high molecular mass smear of ubiquitin conjugates. Finally, apoptotic cell death in treated U266 cells was detected biochemically by measuring the activity of caspases 3 and 7 in lysates and by immunoblotting of caspase 7, its substrate poly(ADP-ribose)polymerase, and Mcl-1, which all together showed changes typical for apoptosis. All these observations were in agreement with expected cellular mechanism of action and confirmed proteasome targeting by prepared O-benzyl salicylamides.
Jorda, Radek,Du?ek, Jan,?ezní?ková, Eva,Pauk, Karel,Magar, Pratibha P.,Imramovsky, Ale?,Kry?tof, Vladimír
supporting information
p. 142 - 158
(2017/04/26)

Synthesis and antiviral activity of novel glycyrrhizic acid conjugates with D-amino acid esters
Glycyrrhizic acid (GA) conjugates with methyl and ethyl esters of D-amino acids (D-Trp, D-Phe, D-Tyr, D-Val, D-Leu) have been synthesized by the activated esters method using mixtures of N-hydroxybenzotriazole or N-hydroxysuccinimide with N,N′-dicyclohexylcarbodiimide. GA conjugate with D-Trp ethyl ester exhibited antiviral activity against influenza viruses A/H3N2, A/H1N1/pdm09, A/H5N1, B (SI > 10–29), and HRSV (SI > 25). GA conjugate with D-Trp methyl ester inhibited influenza virus A/H1N1/pdm09 (SI > 30).
Fayrushina,Baltina,Baltina,Konovalova,Petrova,Eropkin, M. Yu.
p. 456 - 462
(2017/08/08)

Isolation, Structure Elucidation, and (Bio)Synthesis of Haprolid, a Cell-Type-Specific Myxobacterial Cytotoxin
Myxobacteria are well-established sources for novel natural products exhibiting intriguing bioactivities. We here report on haprolid (1) isolated from Byssovorax cruenta Har1. The compound exhibits an unprecedented macrolactone comprising four modified amino acids and a polyketide fragment. As configurational assignment proved difficult, a bioinformatic analysis of the biosynthetic gene cluster was chosen to predict the configuration of each stereocenter. In-depth analysis of the corresponding biosynthetic proteins established a hybrid polyketide synthase/nonribosomal peptide synthetase origin of haprolid and allowed for stereochemical assignments. A subsequent total synthesis yielded haprolid and corroborated all predictions made. Intriguingly, haprolid showed cytotoxicity against several cell lines in the nanomolar range whereas other cells were almost unaffected by treatment with the compound.
Steinmetz, Heinrich,Li, Jun,Fu, Chengzhang,Zaburannyi, Nestor,Kunze, Birgitte,Harmrolfs, Kirsten,Schmitt, Viktoria,Herrmann, Jennifer,Reichenbach, Hans,H?fle, Gerhard,Kalesse, Markus,Müller, Rolf
supporting information
p. 10113 - 10117
(2016/08/16)

γ-Glutamyl-dipeptides: Easy tools to rapidly probe the stereoelectronic properties of the ionotropic glutamate receptor binding pocket
γ-Glutamyl-dipeptides, built by condensing the distal carboxylate of L-Glu (or D-Glu) onto a series of differently functionalized amino acids, were prepared and used as tools for rapidly probing the stereo-electronic properties of iGluRs, searching for subtype-selective ligands.
Tamborini, Lucia,Nicosia, Veronica,Conti, Paola,Dall'Oglio, Federica,De Micheli, Carlo,Nielsen, Birgitte,Jensen, Anders A.,Pickering, Darryl S.,Pinto, Andrea
p. 8486 - 8492
(2016/11/28)

Regiodivergent Enantioselective γ-Additions of Oxazolones to 2,3-Butadienoates Catalyzed by Phosphines: Synthesis of α,α-Disubstituted α-Amino Acids and N,O-Acetal Derivatives
Phosphine-catalyzed regiodivergent enantioselective C-2- and C-4-selective γ-additions of oxazolones to 2,3-butadienoates have been developed. The C-4-selective γ-addition of oxazolones occurred in a highly enantioselective manner when 2-aryl-4-alkyloxazol-5-(4H)-ones were employed as pronucleophiles. With the employment of 2-alkyl-4-aryloxazol-5-(4H)-ones as the donor, C-2-selective γ-addition of oxazolones took place in a highly enantioselective manner. The C-4-selective adducts provided rapid access to optically enriched α,α-disubstituted α-amino acid derivatives, and the C-2-selective products led to facile synthesis of chiral N,O-acetals and γ-lactols. Theoretical studies via DFT calculations suggested that the origin of the observed regioselectivity was due to the distortion energy that resulted from the interaction between the nucleophilic oxazolide and the electrophilic phosphonium intermediate.
Wang, Tianli,Yu, Zhaoyuan,Hoon, Ding Long,Phee, Claire Yan,Lan, Yu,Lu, Yixin
supporting information
p. 265 - 271
(2016/01/25)

A new type of chiral-pyridoxamines for catalytic asymmetric transamination of α-keto acids
A new type of chiral pyridoxamines bearing an adjacent chiral stereocenter has been developed via multi-step synthesis. The pyridoxamines displayed catalytic activity in asymmetric transamination of α-keto acids to give a variety of optically active amino acids in 27–78% yields with 34–62% ee's under very mild conditions. This work provides a synthetic strategy to construct new chiral pyridoxamines using bromopyridine 7 as a key synthon and also represents an early example of the applications of chiral pyridoxamines in asymmetric catalysis.
Chen, Jianfeng,Zhao, Junyu,Gong, Xing,Xu, Dongfang,Zhao, Baoguo
supporting information
p. 4612 - 4615
(2016/09/23)

Large-scale synthesis of Singh's catalyst in a one-pot procedure starting from proline
A practical one-pot procedure for the preparation of Singh's catalyst from either l-/d-proline or Boc-proline is described. The coupling partner, a chiral amino alcohol, can be prepared and used directly without purification from the corresponding amino acid ester. Moreover, a procedure for tert-butoxycarbonyl (Boc) group removal using concentrated HCl in MeOH-DCM was developed and utilized for the multigram-scale synthesis of Singh's catalyst.
Berkessel, Albrecht,Harnying, Wacharee,Duangdee, Nongnaphat,Neudoerfl, Joerg-M.,Groeger, Harald
body text
p. 123 - 128
(2012/05/20)

Highly tunable arylated cinchona alkaloids as bifunctional catalysts
We report the design and evaluation of a library of chiral bifunctional organocatalysts in which the distance between the catalytically active units can be systematically varied.
Quigley, Cormac,Rodriguez-Docampo, Zaida,Connon, Stephen J.
supporting information; scheme or table
p. 1443 - 1445
(2012/03/11)

Synthesis, crystal structure and insecticidal activity of the optical active neonicotinoid analogues
Eight novel neonicotinoid analogues 1-(2-tetrahydrofurfuryl)-5-substituted- 1,3,5-hexahydrotriazine-2-N-nitroimines 3a - 3h were synthesized, and their structures were characterized by 1H NMR, IR and elemental analysis. The stereostructure of 3a was determined by the single-crystal X-ray analysis, which exhibits a half-chair conformation and dihedral angle is 49.70° . The preliminary bioassay tests showed that all the title compounds exhibited good insecticide activities against Nilaparvata legen (N. legen).
Xue, Sijia,Bu, Hongfei,Liu, Li,Xu, Xiao,Ma, Xubo
scheme or table
p. 1011 - 1016
(2012/01/06)

Use of diphenyliodonium bromide in the synthesis of some N-phenyl-amino acids
The N-phenyl methyl esters 4 of glycine, alanine, valine, leucine, isoleucine, phenylalanine, methionine, proline, serine, threonine, tyrosine, aspartic acid, and glutamic acid have been synthesized in good to excellent yields using diphenyliodonium bromide, AgNO3, and a catalytic amount of CuBr starting from the relevant amino acid ester. The chiral integrity of the amino acids 5 was maintained during these reactions, which were confirmed by the synthesis of dipeptide for each N-phenyl amino acid. The structures of the new compounds were confirmed by the analysis of their IR, 1H, and 13C NMR spectra in addition to CHN microanalysis or high-resolution mass spectrometry for the new N-phenyl amino acids 5 and the esters 4.
McKerrow, Jason D.,Al-Rawi, Jasim M. A.,Brooks, Peter
experimental part
p. 1161 - 1179
(2010/04/28)

Tetramic acids as scaffolds: Synthesis, tautomeric and antibacterial behaviour
Efficient synthetic routes for tetramic acids variously substituted on the ring nitrogen, their tautomeric behaviour in solution and their antibiotic activity are reported.
Jeong, Yong-Chul,Moloney, Mark G.
scheme or table
p. 2487 - 2491
(2010/03/01)

Design and synthesis of N-methylmaleimide indolocarbazole bearing modified 2-acetamino acid moieties as Topoisomerase I inhibitors
A novel series of N-methylmaleimide indolocarbazole derivatives bearing modified 2-acetamino acid moieties are first reported. The cytotoxic effects of these compounds were tested in five human tumor cell lines. The potent compounds 9a, 9b, 9d, and 9e have been further evaluated for their effect on Topoisomerase I (TOPO I) and cancer cell cycle. It is concluded that the indolocarbazoles with alkyl piperazine or morpholine substituent groups instead of esters or glycosyl residues would have better activities against tumors.
Li, Zhiyu,Zhai, Fuming,Zhao, Li,Guo, Qinglong,You, Qidong
scheme or table
p. 406 - 409
(2011/02/26)

A convenient synthesis of amino acid methyl esters
A series of amino acid methyl ester hydrochlorides were prepared in good to excellent yields by the room temperature reaction of amino acids with methanol in the presence of trimethylchlorosilane. This method is not only compatible with natural amino acids, but also with other aromatic and aliphatic amino acids.
Li, Jiabo,Sha, Yaowu
p. 1111 - 1119
(2008/09/21)

PREPARATION AND USE OF BIPHENYL-4-YL-CARBONYLAMINO ACID DERIVATIVES FOR THE TREATMENT OF OBESITY
This invention relates to certain biphenyl-4-yl carbonylamino acid compounds, compositions, and methods for treating or preventing obesity and related diseases.
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(2010/11/08)

Application of phosphoramidate ProTide technology significantly improves antiviral potency of carbocyclic adenosine derivatives
We report the application of phosphoramidate pronucleotide (ProTide) technology to the antiviral agent carbocyclic L-d4A (L-Cd4A). The phenyl methyl alaninyl parent ProTide of L-Cd4A was prepared by Grignard-mediated phosphorochloridate reaction and resulted in a compound with significantly improved anti-HIV (2600-fold) and HBV activity. We describe modifications of the aryl, ester, and amino acid regions of the ProTide and how these changes affect antiviral activity and metabolic stability. Separate and distinct SARs were noted for HIV and HBV. Additionally, ProTides were prepared from the D-nucleoside D-Cd4A and the dideoxy analogues L-CddA and D-CddA. These compounds showed more modest potency improvements over the parent drug. In conclusion, the ProTide approach is highly successful when applied to L-Cd4A with potency improvements in vitro as high as 9000-fold against HIV. With a view to preclinical candidate selection we carried out metabolic stability studies using cynomolgus monkey liver and intestinal S9 fractions.
McGuigan, Christopher,Hassan-Abdallah, Alshaimaa,Srinivasan, Sheila,Wang, Yikang,Siddiqui, Adam,Daluge, Susan M.,Gudmundsson, Kristjan S.,Zhou, Huiqiang,McLean, Ed W.,Peckham, Jennifer P.,Burnette, Thimysta C.,Marr, Harry,Hazen, Richard,Condreay, Lynn D.,Johnson, Lance,Balzarini, Jan
p. 7215 - 7226
(2007/10/03)

Optically active α-aminonitrile and process for producing α-amino acid
An aldehyde compound is reacted with an amino compound and hydrogen cyanate in the presence of a chiral zirconium catalyst obtained by mixing a zirconium alkoxide with an optically active binaphthol compound.
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Example 3

(2010/01/30)

N-cholyl amino acid alkyl esters - A novel class of organogelators
Several N-cholyl amino acid alkyl esters were found to act as novel, potent organogelators for aromatic solvents and cyclohexene. These novel organogelators afford stable, transparent, and thermoreversible gels. Modification of the molecular structure and IR measurements show that gelation takes place by means of a hydrogen-bonded network and involves at least the amide bond and several hydroxy groups of the cholic acid component. The chiral center of the amino acid component seems to play an important role in gelation. Although a wide variety of derivatives display gelation behavior, a small change in molecular structure can have a dramatic effect on the gelling capability. Electron microscopy reveals a fibrous structure in the gels. Differential scanning calorimetry shows several transitions in the melting behavior of the gels.
Willemen, Hendra M.,Vermonden, Tina,Marcelis, Antonius T. M.,Sudhoelter, Ernst J. R.
p. 2329 - 2335
(2007/10/03)

Enantioselective reduction of aromatic ketones catalysed by chiral ruthenium(II) complexes
The catalytic enantioselective reduction of aromatic ketones in 2- propanol is carried out by using ruthenium(II) complexes prepared from [Ru(p- cymene)Cl2]2 and a variety of chiral diamines and β-aminoalcohols derived from α-amino acids. Good conversions (>99%) and enantioselectivities (=96%) are observed under mild reaction conditions. (C) 2000 Elsevier Science Ltd.
Aitali,Allaoud,Karim,Meliet,Mortreux
p. 1367 - 1374
(2007/10/03)

beta -thiopropionyl-aminoacid derivatives and their use as beta -lactamase inhibitors
PCT No. PCT/EP97/00516 Sec. 371 Date Jan. 13, 1999 Sec. 102(e) Date Jan. 13, 1999 PCT Filed Feb. 3, 1997 PCT Pub. No. WO97/30027 PCT Pub. Date Aug. 21, 1997A method of treatment of bacterial infections in humans or animals which comprises administering, in combination with a beta -lactam antibiotic, a therapeutically effective amount of an amino acid derivative of Formula (I) or a pharmaceutically acceptable salt, solvate or in vivo hydrolysable ester thereof, wherein: R is hydrogen, a salt forming cation or an in vivo hydrolysable ester-forming group; R1 is hydrogen, (C1-6)alkyl optionally substituted by up to three halogen atoms or by a mercapto, (C1-6)alkoxy, hydroxy, amino, nitro, carboxy, (C1-6)alkylcarbonyloxy, (C1-6)alkoxycarbonyl, formyl or (C1-6)alkylcarbonyl group, (C3-7)cycloalkyl, (C3-7)cycloalkyl(C2-6)alkyl, (C2-6)alkenyl, (C2-6)alkynyl, aryl, aryl(C1-6)alkyl, heterocyclyl or heterocyclyl(C1-6)alkyl; R2 is hydrogen, (C1-6)alkyl or aryl(C1-6)alkyl; R3 is hydrogen, (C1-6)alkyl optionally substituted by up to three halogen atoms, (C3-7)cycloalkyl, fused aryl(C3-7)cycloalkyl, (C3-7)cycloalkyl(C2-6)alkyl, (C2-6)alkenyl, (C2-6)alkynyl, aryl, aryl-(CHR10)m-X-(CHR11)n, heterocyclyl or heterocyclyl-(CHR10)m-X-(CHR11)n, where m is 0 to 3, n is 1 to 3, each R10 and R11 is independently hydrogen or (C1-4)alkyl and X is O, S(O)x where x is 0-2, or a bond; R4 is hydrogen, or an in vivo hydrolysable acyl group; and R5 and R6 are independently hydrogen and (C1-6)alkyl or together represent (CH2)p where p is 2 to 5. Some compounds are claimed per se.
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(2008/06/13)

Chiral Discrimination in the Liquid Phase: Excess Volumes of Binary Mixtures of Amino Acid Derivatives
Volume changes on mixing the enantiomers of N-trifluoroacetylamino acid methyl esters (N-TFA-amino acid-OMe) were determined at 25 deg C by means of a high-precision vibrating-tube densimeter.The excess molar volume (VE) for the racemic mixtures of N-TFA-Ala-OMe 1, N-TFA-Val-OMe 2, and N-TFA-Leu-OMe 3, were found as VE = 0.0098, -0.0458, and 0.035 cm3 mol-1, respectively.For 2 and 3, these volumetric effects of discriminating interactions between enantiomers in the liquid phase are the largest ever observed.
Lepori, Luciano,Koppenhoefer, Beenhard
p. 6862 - 6864
(2007/10/02)

RELATIONSHIPS BETWEEN THE STRUCTURE AND THE PHYTOTOXICITY OF THE FUNGAL TOXIN TENUAZONIC ACID
Tenuazonic acid (3-acetyl 5-sec-butyl pyrrolidine-2,4-dione) is a metabolite produced by the fungal pathogen of rice Pyricularia oryzae.It inhibits growth of plants by interferring with protein synthesis at the ribosome level.We have synthesized analogues of tenuazonic acid with various substituents at C-3 and C-5.Substituents at C-5 other than sec-butyl or n-propyl, decrease the phytotoxicity of the analogues.But substitutions at C-3 abolish the toxicity.Thus, tenuazonic acid seems to have the optimal structure for phytotoxicity.Tenuazonic acid induces rice leaf defence reactions (browning) of reactive varieties which are resistant to P. oryzae.Some of the analogues synthesized have a low level of phytotoxicity and are able to induce this leaf browning of the reactive rice varieties.Thus different structural features are required for phytotoxicity and for leaf browning.Key Word Index - Tenuazonic acid; pyrrolidine-2,4-diones; rice; phytotoxicity; Pyricularia oryzae; structure-activity.
Lebrun, M. H.,Nicolas, L.,Boutar, M.,Gaudemer, F.,Ranomenjanahary, S.,Gaudemer, A.
p. 77 - 84
(2007/10/02)

Metal Complexes with Biologically Important Ligands, XLV. - Palladium(II) Complexes of Dehydro-α-amino and 2-Imino Acid Esters as Ligands
The preparation and spectroscopic data of the complexes trans-Cl2Pd(H2NC(CO2R)=C)2 (1) and trans-Cl2Pd(HN=C(CO2R)-CH)2 (6) and of (+)BF4(-) (2) are reported.The reactions of dehydroamino acid esters R(ROC)-C=C(CO2R)NH2 with Na2PdCl4 give 1-imino-3-ketonato chelate complexes cis- (3), of which one representative (3b) has been characterized by X-ray structure analysis.For comparison the structure of the dehydroamino acid derivative OC(Me)C(CO2Et)=C(CO2Et)NH2 (4) has also been determined.Palladium(II) binds the anion of dehydroarmentomycin via the N,O atoms (8).This coordination is also found with (η5-C5H5)(OC)2Mo and allylglycine (9).
Wanjek, Herbert,Nagel, Ulrich,Beck, Wolfgang
p. 1021 - 1026
(2007/10/02)

AN EFFICIENT SYNTHESIS OF N-HYDROXY-α-AMINO ACID DERIVATIVES OF HIGH OPTICAL PURITY.
Conversion of α-hydroxy esters via triflates into compounds 3 proceeds in chemical yields ranging from 78 to 89percent and with optical purities ranging from 76 to 100percent.
Feenstra, R. W.,Stokkingreef, E. H. M.,Nivard, R. J. F.,Ottenheijm, H. C. J.
p. 1215 - 1218
(2007/10/02)

Synthesis of Optically Active 1,3,2-Oxazaphospholidine 2-Sulfides and 1,3,2-Benzodioxaphosphorin 2-Sulfides
The optical isomers of ten kinds of insecticidal 1,3,2-oxazaphospholidine 2-sulfides (OS) and two kinds of 1,3,2-benzodioxaphosphorin 2-sulfides (BS), including the commercial insecticide salithion, were synthesized in high optical purity by using two optically active aryl methyl phosphorochloridothionates (AMPC) as chiral two-step phosphorylating reagents.Their configurations were assigned according to the reaction mechanism and supported by proton NMR information.
Wu, Shao-Yong,Hirashima, Akinori,Kuwano, Eiichi,Eto, Morifusa
p. 537 - 548
(2007/10/02)

Enzyme-Catalyzed Irreversible Formation of Peptides Containing D-Amino Acids
Procedures have been developed for the preparation of dipeptides Z-L-Tyr-D-X and Z-L-Phe-D-X using Z-L-Tyr-OMe (or Z-L-Phe-OMe) and D-amino acid esters or amides (D-X) as substrates and soluble or immobilized α-chymotrypsin as a catalyst.The formation of each of these peptides in miscible or immiscible organic solvent-water systems in a kinetically controlled approach is virtually irreversible with no side reactions or racemization.Kinetic studies indicate that D-amino acid esters are about 100 times that of water and 10percent that of L-amino acid esters as a nucleophile in deacylation reactions.The effects of pH, organic solvents, temperature, and substrate and enzyme concentrations on the yield and the stability of the enzyme in syntheses have been studied and the results compared with those in the enzyme-catalyzed formation of L-L-dipeptides.
West, J. Blair,Wong, Chi-Huey
p. 2728 - 2735
(2007/10/02)