- Asymmetric synthesis of the central tryptophan residue of stephanotic acid
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The C-6 substituted tryptophan di- and tri-peptides 5 and 6, representing the tryptophan core of stephanotic acid, have been synthesized, the key steps being the formation of the phosphono-di- and tri-peptides 8 and 10 by a highly chemo-selective rhodium(II) catalyzed carbene N-H insertion reaction, their subsequent Horner-Wadsworth-Emmons reactions with N-Boc-6-bromoindole-3- carboxaldehyde, and the rhodium(I) catalyzed asymmetric hydrogenation of the resulting dehydro di- and tri-peptides.
- Bentley, David J.,Moody, Christopher J.
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Read Online
- Holzapfel-Meyers-Nicolaou modification of the Hantzsch thiazole synthesis
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Modified conditions for Hantzsch thiazole synthesis provides valine- and threonine-derived thiazoles without significant loss of optical purity. This two- or three-step procedure proceeds by the cyclocondensation of the corresponding thioamide under basic conditions, according to modified methods of Meyers and Holzapfel. The hydroxythiazoline intermediate is then dehydrated by treatment with trifluoroacetic anhydride-pyridine, followed by triethylamine, according to Nicolaou's procedure. Solvolysis of the trifluoroacetamide derivative produced in this process can be affected with sodium ethoxide in ethanol to give a reliable method for the stereoselective synthesis of functionalised thiazole building blocks in high yield. Georg Thieme Verlag Stuttgart.
- Merritt, Eleanor A.,Bagley, Mark C.
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Read Online
- Design, synthesis and cytotoxic evaluation of a library of oxadiazole-containing hybrids
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The development of hybrid compounds led to the discovery of new pharmacologically active agents for some of the most critical diseases, including cancer. Herein, we describe a new series of oxadiazole-containing structures designed by a molecular hybridiz
- Camacho, Cristián M.,Pizzio, Marianela G.,Roces, David L.,Boggián, Dora B.,Mata, Ernesto G.,Bellizzi, Yanina,Barrionuevo, Elizabeth,Blank, Viviana C.,Roguin, Leonor P.
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p. 29741 - 29751
(2021/10/07)
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- COMPOSITION COMPRISING OXALAMIDE GELATORS AND VEGETABLE OIL
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The present invention relates to the composition with gelling properties comprising oxalamide gelators of Formula (I) and a vegetable oil. Uses of such composition in the food, cosmetic or pharmaceutical industry are disclosed.
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Page/Page column 13
(2020/07/14)
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- Development of new catalytic enantioselective formation of methylenelactam-based N,O-spirocyclic compounds via ring opening-asymmetric reclosure of hydroxylactams
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Catalytic enantioselective formation of methylenelactam-based N,O-spirocyclic compounds is developed. Hydroxylactams prepared from N-carbonyl phthalimides and β-amido functionalized allylboronates underwent ring opening-asymmetric reclosure in the presence of catalytic amounts of MgBr2 and a chiral aminophenol to afford the corresponding N,O-spirocyclic compounds in excellent yields and high enantioselectivities.
- Sengoku, Tetsuya,Miyoshi, Ayako,Tsuda, Tamaki,Inuzuka, Toshiyasu,Sakamoto, Masami,Takahashi, Masaki,Yoda, Hidemi
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- Singlet Oxygen Photooxidation of Peptidic Oxazoles and Thiazoles
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Oxazoles and thiazoles are commonly found moieties in nonribosomal peptides (NRPs) and ribosomally synthesized post-translationally modified peptides (RiPPs), which are important biomolecules present in the environment and in natural waters. From previous studies, they seem susceptible to oxidation by singlet oxygen (1O2); therefore, we designed and synthesized model oxazole- and thiazole-peptides and measured their1O2 bimolecular reaction rate constants, showing slow photooxidation under environmental conditions. We reasoned their stability through the electron-withdrawing effect of the carboxamide substituent. Reaction products were elucidated and support a reaction mechanism involving cycloaddition followed by a series of rearrangements. The first1O2 bimolecular reaction rate constant for a RiPP, the thiazole-containing peptide Aerucyclamide A, was measured and found in good agreement with the model peptide's rate constant, highlighting the potential of using model peptides to study the transformations of other environmentally relevant NRPs and RiPPs.
- Manfrin, Alessandro,Borduas-Dedekind, Nadine,Lau, Kate,McNeill, Kristopher
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p. 2439 - 2447
(2019/02/26)
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- Novel Fubinaca/Rimonabant hybrids as endocannabinoid system modulators
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The discovery of novel modulators of the cannabinoid system is a current topic in medicinal chemistry. In this paper, we report nine novel carboxamides designed as hybrids of Fubinaca family compounds and Rimonabant. These hybrids were obtained by linking the 1-benzyl-2,5-dichloroindazole-3-carboxylic acid to different amino acids bearing a hydrophobic side chain and three different C-terminus. The new chemical entities were tested in vitro to evaluate their bioactivity by means of receptor binding assays and [35S]GTPγS stimulation assays to reveal their affinity and potency. We found that all compounds were able to bind to the cannabinoid receptors in the low nanomolar range with a marked selectivity towards the CB1 cannabinoid receptor. Some of them are full agonists, whereas the others act as partial agonists. These molecules could be potentially used as anti-obesity agents, antiemetic and analgesics.
- Stefanucci, Azzurra,Macedonio, Giorgia,Dvorácskó, Szabolcs,T?mb?ly, Csaba,Mollica, Adriano
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p. 1595 - 1605
(2018/09/14)
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- Amidation of carboxylic acids via the mixed carbonic carboxylic anhydrides and its application to synthesis of antidepressant (1S,2R)-tranylcypromine
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Primary amidations of carboxylic acids 1 or 3 with NH4Cl in the presence of ClCO2Et and Et3N were developed to afford the corresponding primary amides in 22% to quantitative yields. Additionally, we have applied the amidation to the preparation of various amides containing hydroxamic acids and achieved the synthesis of (1S,2R)-tranylcypromine as an antidepressant medicine via Lossen rearrangement.
- Ezawa, Tetsuya,Kawashima, Yuya,Noguchi, Takuya,Jung, Seunghee,Imai, Nobuyuki
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p. 1690 - 1699
(2017/11/14)
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- Total Synthesis of the Cyclic Dodecapeptides Wewakazole and Wewakazole B
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The cyclic dodecapeptides wewakazole and wewakazole B have been synthesized by a divergent strategy via a common tris-proline containing oxazole octapeptide and two separate bis-oxazole containing tetrapeptide units, followed by peptide coupling and macro
- Inman, Martyn,Dexter, Hannah L.,Moody, Christopher J.
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supporting information
p. 3454 - 3457
(2017/07/15)
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- RITA Mimics: Synthesis and Mechanistic Evaluation of Asymmetric Linked Trithiazoles
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The established cytotoxic agent RITA contains a thiophene-furan-thiophene backbone and two terminal alcohol groups. Herein we investigate the effect of using thiazoles as the backbone in RITA-like molecules and modifying the terminal groups of these trithiazoles, thereby generating 41 unique structures. Incorporating side chains with varied steric bulk allowed us to investigate how size and a stereocenter impacted biological activity. Subjecting compounds to growth inhibition assays on HCT-116 cells showed that the most potent compounds 7d, 7e, and 7h had GI50 values of 4.4, 4.4, and 3.4 μM, respectively, versus RITA (GI50 of 800 nM). Analysis of these compounds in apoptosis assays proved that 7d, 7e, and 7h were as effective as RITA at inducing apoptosis. Evaluating the impact of 7h on proteins targeted by RITA (p53, c-Myc, and Mcl-1) indicated that it acts via a different mechanism of action to that of RITA. RITA suppressed Mcl-1 protein via p53, whereas compound 7h suppressed Mcl-1 expression via an alternative mechanism independent of p53.
- Pietkiewicz, Adrian L.,Zhang, Yuqi,Rahimi, Marwa N.,Stramandinoli, Michael,Teusner, Matthew,McAlpine, Shelli R.
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supporting information
p. 401 - 406
(2017/04/21)
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- Studies on the synthesis of peptides containing dehydrovaline and dehydroisoleucine based on copper-mediated enamide formation
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The preparation of peptide fragments containing dehydrovaline and dehydroisoleucine moieties present in the antibiotic myxovalargin is reported. Peptide formation is based on a copper-mediated C-N cross-coupling protocol between an acyl amide and a peptidic vinyl iodide. The presence of a neighboring arginine in the vinyl iodide posed a challenge with respect to the choice of the protecting group and the reaction conditions. It was found that ornithine - a suitable precursor - is better suited than arginine for achieving good yields for the C-N cross-coupling reaction. The optimized conditions were utilized for the synthesis of peptides 32, 33, 39 and 40 containing a neighboring ornithine as well as for the tripeptide 44 containing dehydroisoleucine with the correct stereochemistry.
- Gille, Franziska,Kirschning, Andreas
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supporting information
p. 564 - 570
(2016/04/08)
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- Isolation, Structure Elucidation, Biosynthesis, and Synthesis of Antalid, a Secondary Metabolite from Polyangium species
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The isolation, structure elucidation, and synthesis of antalid (1), a novel secondary metabolite from Polyangium sp., is described herein. The structure elucidation of 1 was performed with the aid of mass spectrometry, high field NMR experiments, and crystal structure analysis. The absolute configuration of antalid was confirmed through the Mosher ester method and ultimately by total synthesis. In addition, the biosynthetic origin of this hybrid PKS-NRPS natural product was unraveled by the in silico analysis of its biosynthetic gene cluster.
- Tautz, Thomas,Hoffmann, Judith,Hoffmann, Thomas,Steinmetz, Heinrich,Washausen, Peter,Kunze, Brigitte,Huch, Volker,Kitsche, Andreas,Reichenbach, Hans,H?fle, Gerhard,Müller, Rolf,Kalesse, Markus
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supporting information
p. 2560 - 2563
(2016/06/15)
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- [2,3]-sigmatropic rearrangement of allylic selenimides: Strategy for the synthesis of peptides, peptidomimetics, and N-aryl vinyl glycines
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The scope of the NCS-mediated amination/[2,3]-sigmatropic rearrangement of enantioenriched allylic selenides has been expanded to provide access to three new product classes. The use of N-protected amino acid amides provides a novel strategy for accessing peptide chains containing unnatural vinyl glycine amino acid residues. Also reported is the use of amino acid esters, allowing the diastereoselective synthesis of N,N-dicarboxymethylamines, a motif found in a number of pharmaceuticals. Furthermore, use of a range of N-aromatic and N-heteroaromatic amines allows the formation of enantioenriched N-arylamino acids, a motif found in a number of synthetically and biologically interesting compounds.
- Armstrong, Alan,Emmerson, Daniel P. G.,Milner, Harry J.,Sheppard, Robert J.
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p. 3895 - 3907
(2014/05/20)
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- One-pot synthesis of orthogonally protected dipeptide selenazoles employing Nα-amino selenocarboxamides and α-bromomethyl ketones
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A simple and efficient protocol for the synthesis of selenazole containing dipeptidomimetics using Nα-amino selenocarboxamides and α-bromomethyl ketones is described. All the compounds made were isolated in good yields and fully characterized.
- Madhu, Chilakapati,Panguluri, Nageswara Rao,Narendra,Panduranga,Sureshbabu, Vommina V.
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supporting information
p. 6831 - 6835
(2015/01/09)
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- Design, synthesis, and biological evaluation of (S)-valine thiazole-derived cyclic and noncyclic peptidomimetic oligomers as modulators of human P-glycoprotein (ABCB1)
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Multidrug resistance caused by ATP binding cassette transporter P-glycoprotein (P-gp) through extrusion of anticancer drugs from the cells is a major cause of failure in cancer chemotherapy. Previously, selenazole-containing cyclic peptides were reported
- Singh, Satyakam,Prasad, Nagarajan Rajendra,Kapoor, Khyati,Chufan, Eduardo E.,Patel, Bhargav A.,Ambudkar, Suresh V.,Talele, Tanaji T.
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p. 157 - 169
(2014/01/06)
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- "Backdoor Induction" of chirality in asymmetric hydrogenation with rhodium(I) complexes of amino acid substituted triphenylphosphane ligands
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This paper describes the synthesis and characterization of 5-(diphenylphosphanyl)isophthalic acid bioconjugates (Lig-[R]2). In addition to symmetrically disubstituted conjugates with amino acids, peptides or amines, a convenient one-pot, two-step procedure for the synthesis of conjugates bearing two different substituents is reported. The 28 prepared phosphanes were used as monodentate ligands in the rhodium(I)-catalyzed hydrogenation of 2-acetamidoacrylate and (Z)-α-acetamidocinnamate. The ligand with the smallest side-chain substituents Lig-[Ala-OMe]2 (1a) revealed the highest selectivity, with up to 84 % ee. The catalysts presented herein are models of artificial metalloenzymes in which the outer-coordination sphere controls the selectivity in catalysis. The chirality of distant hydrogen-bonded amino acids is transmitted by "backdoor induction" to the prochiral RhI center. Models of artificial metalloenzymes are presented in which the outer-coordination sphere controls the selectivity in catalysis. The chirality of distant hydrogen-bonded amino acids or amines is transmitted by "backdoor induction" to the prochiral RhI center. Copyright
- Kokan, Zoran,Kirin, Srecko I.
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supporting information
p. 8154 - 8161
(2014/01/06)
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- Synthesis of the thiazole-thiazoline fragment of largazole analogues
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The thiazole - thiazoline fragment of the marine natural product largazole, a potent histone deacetylase 1 inhibitor, has been synthesized in five steps. The methodology provides rapid access to thiazole-4-carbonitrile, thiazole-4-carbimidate, thiazole -
- Diness, Frederik,Nielsen, Daniel S.,Fairlie, David P.
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experimental part
p. 9845 - 9851
(2012/01/02)
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- Carbamates of 4′-demethyl-4-deoxypodophyllotoxin: Synthesis, cytotoxicity and cell cycle effects
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In an attempt to generate compounds with superior bioactivity and reduced toxicity, 12 carbamates of 4′-demethyl-4-deoxypodophyllotoxin, N-(1-oxyl-4′-demethyl- 4-deoxypodophyllic)-α-amino acids amides, were synthesized and evaluated for antiproliferative activity and cell cycle effects. These synthesized compounds proved to be more hydrophilic, as well as improved or comparable in vitro cytotoxicities against four cell lines (A-549, HeLa, SiHa, and HL-60) compared with either parent DPT or anti-cancer drug VP-16. Furthermore, flow cytometric analysis exhibited that N-(1-oxyl-4′- demethyl-4-deoxypodophyllic)-d-α-methine amide (15f) induced cell cycle arrest in the G2/M phase in A-549 cells.
- Chen, Shi-Wu,Gao, Yuan-Yu,Zhou, Ni-Ni,Liu, Jie,Huang, Wen-Ting,Hui, Ling,Jin, Yan,Jin, Yong-Xin
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supporting information; experimental part
p. 7355 - 7358
(2012/02/04)
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- Isoselenocyanates derived from Boc/Z-amino acids: Synthesis, isolation, characterization, and application to the efficient synthesis of unsymmetrical selenoureas and selenoureidopeptidomimetics
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Isoselenocyanates derived from Boc/Z-amino acids are prepared by the reaction of the corresponding isonitriles with selenium powder in presence of triethylamine at reflux. The utility of these new classes of isoselenocyanates in the preparation of selenoureidodipeptidomimetics possessing both amino as well as carboxy termini has been accomplished. The 1H NMR analysis confirmed that the protocol involving the conversion of isonitriles to isoselenocyanates and their use as coupling agents in assembling selenoureido derivatives is free from racemization.
- Chennakrishnareddy, Gundala,Nagendra, Govindappa,Hemantha, Hosahalli P.,Das, Ushati,Guru Row, Tayur N.,Sureshbabu, Vommina V.
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supporting information; experimental part
p. 6718 - 6724
(2010/09/30)
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- Design and synthesis of dipeptidyl nitriles as potent, selective, and reversible inhibitors of cathepsin C
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A series of dipeptide nitriles with a thienyl alanine in P2 were identified as potent and selective cathepsin C inhibitors. Incorporation of a substituted cyclopropyl moiety in P1 effectively protects these derivatives against hydrolase activity in whole blood.
- Guay, Daniel,Beaulieu, Christian,Jagadeeswar Reddy,Zamboni, Robert,Methot, Nathalie,Rubin, Joel,Ethier, Diane,David Percival
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scheme or table
p. 5392 - 5396
(2010/05/02)
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- The preparation of optically active α-amino 4H-[1,2,4]oxadiazol-5-ones from optically active α-amino acids
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Optically active α-amino 4H-[1,2,4]oxadiazol-5-ones (oxadiazolones) were prepared from optically active α-amino acids in five synthetic steps. The oxadiazolone moiety serves as a bioisosteric replacement for the carboxylic acid. Incorporation of an α-amino oxadiazolone into a representative dipeptide mimic is described.
- Mangette, John E.,Johnson, Matthew R.,Le, Van-Duc,Shenoy, Rajesh A.,Roark, Howard,Stier, Michael,Belliotti, Thomas,Capiris, Thomas,Guzzo, Peter R.
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experimental part
p. 9536 - 9541
(2009/12/28)
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- Synthesis of Boc-amino tetrazoles derived from α-amino acids
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A simple route for the synthesis of Boc-protected tetrazole analogs of amino acids starting from Nα-Boc amino acids has been described. The [2 + 3] cycloaddition of Boc-α-amino nitrile and sodium azide in the presence of a catalytic amount of zinc bromide yielded the desired tetrazoles in good yields and purity. All the compounds obtained have been characterized by 1H and 13C-NMR and mass spectral studies. Copyright Taylor & Francis Group, LLC.
- Sureshbabu, Vommina V.,Naik, Shankar A.,Nagendra
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experimental part
p. 395 - 406
(2009/06/06)
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- N-urethane-protected amino alkyl isothiocyanates: Synthesis, isolation, characterization, and application to the synthesis of thioureidopeptides
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(Chemical Equation Presented) Synthetically useful N-Fmoc amino-alkyl isothiocyanates have been described, starting from protected amino acids. These compounds have been synthesized in excellent yields by thiocarbonylation of the monoprotected 1,2-diamines with CS2/TEA/p-TsCl, isolated as stable solids, and completely characterized. The procedure has been extended to the synthesis of amino alkyl isothiocyanates from Boc- and Z-protected amino acids as well. The utility of these isothiocyanates for peptidomimetics synthesis has been demonstrated by employing them in the preparation of a series of dithioureidopeptide esters. Boc-Gly-OH and Boc-Phe-OH derived isothiocyanates 9a and 9c have been obtained as single crystals and their structures solved through X-ray diffraction. They belong to the orthorhombic crystal system, and have a single molecule in the asymmetric unit (Z′ = 1). 9a crystallizes in the centrosymmetric space group Pbca, while 9c crystallizes in the noncentrosymmetric space group P212121.
- Sureshbabu, Vommina V.,Naik, Shankar A.,Hemantha,Narendra,Das, Ushati,Guru Row, Tayur N.
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supporting information; experimental part
p. 5260 - 5266
(2009/12/06)
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- Synthesis of 3,5-disubstituted 1,2,4-oxadiazoles as peptidomimetic building blocks
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Twelve new 1,2,4-oxadiazole based compounds have been synthesized. Their structures contain a protected amine and a carboxyl or an ester group, and thus serve as potential peptidomimetic building blocks. The synthetic route is simple and mild conditions are used so that the chirality of the starting amino acids is retained.
- Jakopin, ?iga,Ro?kar, Robert,Dolenc, Marija Sollner
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p. 1465 - 1468
(2008/02/02)
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- Total synthesis of the thiazolyl peptide GE2270 A
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(Chemical Equation Presented) When one door closes, another opens: In the synthesis of the thiazolyl peptide GE2270 A (1), the bonds labeled I and II at the pyridine core were established by two consecutive cross-coupling reactions. Amide bond formation (
- Mueller, H. Martin,Delgado, Oscar,Bach, Thorsten
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p. 4771 - 4774
(2008/02/10)
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- Structure-based design of agents targeting the bacterial ribosome
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Rational structure-based drug design has been applied to the antibiotic thiostrepton, in an attempt to overcome some of its' limitations. The identification of a proposed binding fragment allowed construction of a number of key fragments, which were derivatised to generate a library of potential antibiotics. These were then evaluated to determine their ability to bind to the L11 binding domain of the prokaryotic ribosome and inhibit bacterial protein translation.
- Bower, Justin,Drysdale, Martin,Hebdon, Richard,Jordan, Allan,Lentzen, Georg,Matassova, Natalia,Murchie, Alastair,Powles, Jenifer,Roughley, Stephen
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p. 2455 - 2458
(2007/10/03)
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- Convenient syntheses of fragment B and linear main skeleton [fragment A-B-C'] derivatives of an antibiotic, GE 2270 A
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Convenient synthesis of the protected linear precursor [Fragment A-B-C'] of a macrocyclic antibiotic, GE 2270 A, was achieved by coupling of a 2,3,6-tristhiazolyl-substituted pyridine skeleton [Fragment A-C'] with a thiazoloyl-thiazole segment [Fragment B]. The Fragment B was synthesized from an appropriate thioamide and β-bromo-α-oxoalkanoate, the latter of which was first derived by consecutive β-bromination and hydrolytic removal of the α-(N-Boc)amino group of an α-dehydroamino acid ester.
- Suzuki, Taishi,Nagasaki, Atsushi,Okumura, Kazuo,Shin, Chung-gi
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p. 835 - 840
(2007/10/03)
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- Synthesis, anti-inflammatory and antimicrobial activities of new 1,2,4-oxadiazoles peptidomimetics
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A new series of 1,2,4-oxadizoles 6a-g have been synthesised in good yields using the peptide synthesis strategy. The prepared compounds were tested for anti-inflammatory and antimicrobial activities. The anti-inflammatory activities were determined in the
- Leite, Ana Cristina L.,Vieira, Renata F.,De Faria, Antonio R.,Wanderley, Almir G.,Afiatpour, Parviz,Ximenes, Eulalia Camelo P. A.,Srivastava, Rajendra M.,De Oliveira, Claudia F.,Medeiros,Antunes, Edson,Brondani, Dalci J.
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p. 719 - 724
(2007/10/03)
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- Synthesis of functionalised oxazoles and bis-oxazoles
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A new method for the synthesis of oxazoles, and in particular chiral non-racemic oxazoles derived from amino acids, has been developed. Thus, rhodium(II) catalysed reaction of diazocarbonyl compounds 6 and 11 in the presence of amides 8 and 10 results in regioselective insertion of the carbenoid into the amide N-H bond with formation of the β-carbonyl amides 9 and 12. Cyclodehydration of amides 9 and 12 using triphenylphosphine-iodine-triethylamine gives functionalised oxazoles 7 and 13. The oxazoles 13c and 13f were converted into the bis-oxazoles 17a and 17b by a second rhodium(II) catalysed regioselective N-H insertion reaction on the amides 15, followed by cyclodehydration.
- Bagley, Mark C.,Buck, Richard T.,Hind, S. Lucy,Moody, Christopher J.
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p. 591 - 600
(2007/10/03)
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- Retroviral protease inhibitors
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The present invention provides compounds, more particularly dipeptide analogs, which bind to retroviral proteases. These compounds are inhibitors of retroviral proteases and are useful for treating diseases related to infection by retroviruses.
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- Synthesis and activity of HIV protease inhibitors
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We report here the synthesis and activity of HIV protease inhibitors. In the first stage hydrophobic compounds incorporating a 'carba' bond surrogate or a beta-homologated residue were synthesized. Secondly, we synthesized cyclic compounds in which we incorporated 2-quinoline carboxylic acid in the P3 position and the amino-hydroxyindane moiety in the P'3. The last part of this work was dedicated to a structure/activity study of a peptide substrate. These modifications allowed us to work up the synthesis of new pseudopeptide bonds: amino-amide and hydroxy-amide. Compounds with activity in the micromolar range were actually a starting point for the synthesis of new protease inhibitors.
- Garrouste, Patrick,Pawlowski, Macek,Tonnaire, Thierry,Sicsic, Sames,Dumy, Pascal,De Rosny, Eve,Reboud-Ravaux, Michele,Fulcrand, Pierre,Martinez, Jean
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p. 423 - 436
(2007/10/03)
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- Oxidation of oxazolines and thiazolines to oxazoles and thiazoles. Application of the Kharasch-Sosnovsky reaction
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Using a modification of the Kharasch-Sosnovsky reaction, the oxidation of oxazolines and thiazolines bearing a variety of 2-alkyl substituents (chiral and achiral) were smoothly oxidized to their corresponding oxazoles and thiazoles, respectively. The key feature involved in the successful implementation of this important oxidation was the use of a mixture of Cu(I) and Cu(II) salts to enhance the oxidation of the intermediate captodative radical, 24. The main limitation of this method was shown when the oxidation failed with oxazolines/thiazolines lacking the carboalkoxy group at C-4.
- Meyers,Tavares, Francis X.
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p. 8207 - 8215
(2007/10/03)
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- Degradation studies of antibiotic MDL 62,879 (GE2270A) and revision of the structure
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Fragments of the thiopeptide antibiotic MDL 62,879 (GE2270A) were prepared under mild degradation conditions. Their structures were determined by spectroscopic techniques and by comparison to synthetic reference thiazolyl dipeptides. The two thiazolyl ami
- Tavecchia,Gentili,Kurz,Sottani,Bonfichi,Selva,Lociuro,Restelli,Ciabatti
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p. 4867 - 4890
(2007/10/02)
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- Enol esters as intermediates for the facile conversion of amino acids into amides and dipeptides
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N-Protected amino enol esters are easily transformed at room temperature into amino amides, and in the presence of potassium cyanide as catalyst, into tertiary amides and dipeptides.
- Kabouche,Bruneau,Dixneuf
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p. 5359 - 5362
(2007/10/02)
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- Convenient Synthesis of N-Protected Amino Acid Amides
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Boc- or Z-amino acids were conveniently amidated at room temperature by a one-pot procedure employing ammonium hydrogencarbonate and N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline in yields of 81-96percent.The benzyl ester-type protector for the side chains of aspartic acid and glutamic acid was not affected by the procedure.
- Nozaki, Sukekatsu,Muramatsu, Ichiro
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p. 2647 - 2648
(2007/10/02)
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- DESIGN AND SYNTHESIS OF A MULTI-DETACHABLE BENZHYDRYLAMINE-RESIN FOR SOLID PHASE PEPTIDE SYNTHESIS
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Peptides with C-terminal α-carboxamides were synthesized from a multi-detachable benzhydrylamine-resin containing a Boc-(4-acetoxy)benzhydrylamine handle of unambiguous origin.The peptides bound to the new resin are stable to trifluoroacetic acid, but are cleavable by hydrogen fluoride, base and nucleophiles to give unprotected or protected peptide fragments.
- Tam, James P.,DiMarchi, Richard D.,Merrifield, R. B.
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p. 2851 - 2854
(2007/10/02)
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