- Capsicum annuum fruit extract: A novel reducing agent for the green synthesis of zno nanoparticles and their multifunctional applications
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A simple, efficient and convenient method for the preparation of zinc oxide (ZnO) nanoparticle was described. Several parameters like size and morphology of the prepared nanoparticles were characterized thorough a variety of analytical techniques such as
- Lalithamba, Haraluru Shankraiah,Raghavendra, Mahadevaiah,Uma, Kogali,Yatish, Kalanakoppal Venkatesh,Mousumi, Das,Nagendra, Govindappa
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p. 354 - 364
(2018/07/05)
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- Iron-catalyzed peroxidation-carbamoylation of alkenes with hydroperoxides and formamides: Via formyl C(sp2)-H functionalization
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A reaction protocol in which FeCl3 and tert-butyl hydroperoxide facilitated a selective radical coupling reaction of aryl alkenes or 1,3-enynes with tert-butyl hydroperoxide and formamides to prepare an array of β-peroxy amides has been achieved. The β-peroxy amide could serve as a synthetic precursor which was facilely converted to β-hydroxy amide, β-keto amide and β-lactam following subsequent chemical transformation.
- Cheng, Jun-Kee,Shen, Liang,Wu, Liu-Hai,Hu, Xu-Hong,Loh, Teck-Peng
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supporting information
p. 12830 - 12833
(2017/12/06)
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- Formamide Synthesis through Borinic Acid Catalysed Transamidation under Mild Conditions
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A highly efficient and mild transamidation of amides with amines co-catalysed by borinic acid and acetic acid has been reported. A wide range of functionalised formamides was synthesized in excellent yields, including important chiral α-amino acid derivatives, with minor racemisation being observed. Experiments suggested that the reaction rely on a cooperative catalysis involving an enhanced boron-derived Lewis acidity rather than an improved Br?nsted acidity of acetic acid. Amide bonds are reputedly difficult to activate due to their high resonance stabilization. An unusual mild activation of dimethylformamide and formamide by borinic acid 1 (see scheme), illustrated by a general formylation of a wide range of amines, including chiral α-amino esters, has been reported.
- Mohy El Dine, Tharwat,Evans, David,Rouden, Jacques,Blanchet, Jér?me
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supporting information
p. 5894 - 5898
(2016/04/26)
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- Effective Formylation of Amines with Carbon Dioxide and Diphenylsilane Catalyzed by Chelating bis(tzNHC) Rhodium Complexes
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The reductive formylation of amines using CO2 and hydrosilanes is an attractive method for incorporating CO2 into valuable organic compounds. However, previous systems required either high catalyst loadings or high temperatures to achieve high efficiency, and the substrate scope was mostly limited to simple amines. To address these problems, a series of alkyl bridged chelating bis(NHC) rhodium complexes (NHC=N-heterocyclic carbene) have been synthesized and applied to the reductive formylation of amines using CO2 and Ph2SiH2. A rhodium-based bis(tzNHC) complex (tz=1,2,3-triazol-5-ylidene) was identified to be highly effective at a low catalyst loading and ambient temperature, and a wide substrate scope, including amines with reducible functional groups, were compatible. Beyond the norm: Rhodium complexes bearing a strong electron-donating bis(1,2,3-triazol-5-ylidene) ligand were found to be excellent catalysts for the reductive formylation of amines with CO2 and Ph2SiH2 at ambient temperature. The catalyst system possesses a broad substrate scope which tolerates a variety of reducible functional groups and is suitable for the synthesis of bioactive compounds. Tf=trifuoromethanesulfonyl.
- Nguyen, Thanh V. Q.,Yoo, Woo-Jin,Kobayashi
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supporting information
p. 9209 - 9212
(2015/08/06)
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- ENOPEPTINS, USES THEREOF, AND METHODS OF SYNTHESIS THERETO
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Provided herein are inventive enopeptin compounds of Formula (I): and pharmaceutically acceptable salts thereof, and pharmaceutical compositions thereof. Further provided are methods of preparation, use, and treatment.
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Page/Page column 76
(2012/10/18)
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- Investigation of the configurational stabilities of chiral isocyanoacetates in multicomponent reactions
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Isocyanoacetates are uniquely reactive compounds characterized by an ambivalent isocyano functional group and an enolizable α-carbon. It is widely believed that chiral α-substituted isocyanoacetates are configurationally unstable in some synthetically use
- Carney, Daniel W.,Truong, Jonathan V.,Sello, Jason K.
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experimental part
p. 10279 - 10285
(2012/02/14)
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- A remarkably simple protocol for the N -formylation of amino acid esters and primary amines
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A simple, convenient, and wide scope protocol for the N-formylation of amino acid esters and primary amines has been developed utilizing only imidazole in warm DMF.
- Suchy, Mojmir,Elmehriki, Adam A. H.,Hudson, Robert H. E.
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supporting information; experimental part
p. 3952 - 3955
(2011/09/19)
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- Isoselenocyanates derived from amino acid esters: An expedient synthesis and application to the assembly of selenoureidopeptidomimetics, unsymmetrical Selenoureas and selenohydantoins
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An important class of organoselenium compounds-α-isoselenocyanato esters 4 hasbeen prepared by a reaction of α-isocyano esters with elemental selenium powder. The reaction issimple, rapid and all the isoselenocyanates havebeen isolated as stable ones after chromatographic purification. These hitherto unreported classes of molecules would be useful building blocks for the preparation of variety of selenium containing peptidomimetics. In this study, the utility of the title molecules in the preparation of selenoureidopeptidomimetics 6, unsymmetrical selenoureas 8 and selenohydantoins 10 isdemonstrated.
- Hemantha, Hosahalli P.,Sureshbabu, Vommina V.
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scheme or table
p. 644 - 651
(2011/09/14)
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- Diversity-oriented synthesis of cyclic acyldepsipeptides leads to the discovery of a potent antibacterial agent
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A class of cyclic acyldepsipeptide antibiotics collectively known as the enopeptins has recently attracted much attention because of their activity against multidrug-resistant bacteria, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis. These antibiotics are further distinguished by their novel mechanism of action in which they bind and deregulate the tightly controlled activity of the cytoplasmic protease ClpP. Although the natural products have poor pharmacological properties, a synthetic derivative called acyldepsipeptide 4 (ADEP 4) showed remarkable antibacterial activity both in vitro and in mouse models of bacterial infections. A novel route to the ADEP 4 peptidolactone core structure, featuring the Joullié-Ugi three-component reaction, was developed. This multicomponent reaction and a related multicomponent reaction, the Ugi four-component reaction, were used to prepare analogs that were designed using the principles of conformational analysis. These cyclic acyldepsipeptides were tested for their activity against drug-resistant, clinical isolates of Staphylococci and Enterococci. One ADEP 4 analog in which the pipecolate was replaced by 4-methyl pipecolate exhibited in vitro antibacterial activity against Enterococci that was fourfold higher than the parent compound.
- Socha, Aaron M.,Tan, Nicholas Y.,Laplante, Kerry L.,Sello, Jason K.
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experimental part
p. 7193 - 7202
(2010/12/25)
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- Environmentally benign process for the synthesis of N-formyl amino acid esters
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Several amino acid ester hydrochlorides were reacted with ammonium formate to give N-formyl amino acid esters in good yields.
- Kotha, Sambasivarao,Behera, Manoranjan,Khedkar, Priti
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p. 7589 - 7590
(2007/10/03)
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- A new, simple procedure for the synthesis of formyl amides
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A simple and mild method for the N-formylation of amines and α-amino esters is described via reaction with 2-chloro-4,6-dimethoxy[1,3,5]triazine and formic acid. The reaction can be accelerated under microwave irradiation and yields the N-formyl species in high yields and without racemization in the case of optically active α-amino esters.
- De Luca, Lidia,Giacomelli, Giampaolo,Porcheddu, Andrea,Salaris, Margherita
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p. 2570 - 2572
(2007/10/03)
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- Process for preparing N-formylamino carboxylic esters
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The invention relates to a process for preparing N-formylamino carboxylic esters by reacting amino carboxylic acids with formic esters.
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- Enantioselective reduction of aromatic ketones catalysed by chiral ruthenium(II) complexes
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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
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p. 1367 - 1374
(2007/10/03)
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- A mild method for formylating amino esters without using any formulating agent
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A simple and mild method for the N-formylation of α-amino esters is described via an intermediate oxaziridine. This procedure avoids the necessity of specific formylating agents and yields the N-formyl species in high yield and without racemization.
- Giard, Thierry,Bénard, Didier,Plaquevent, Jean-Christophe
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p. 297 - 300
(2007/10/03)
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- A simple and convenient synthesis of N-formyl amino acid esters under mild conditions
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A variety of amino acid ester hydrochlorides react with cyanomethyl formate at room temperature to give the N-formyl amino acid esters in good yields and without racemization.
- Duczek,Deutsch,Vieth,Niclas
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- THE TRANSFORMYLATION REACTION - TRANSFER OF AN N-FORMYL RESIDUE IN AMINO ACID AND PEPTIDE DERIVATIVES TO NUCLEOPHILIC GROUPS - AS A SIDE REACTION OF PEPTIDE SYNTHESIS
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In the course of a study of the enzymatic synthesis of peptides from N-formylamino acids, the transfer of a formyl group to nucleophilic acceptors present in the aqueous-organic reaction medium - amino acid esters, peptides, and aromatic amines - has been detected, and this to the greater degree the higher the nucleophilicity of the acceptor.The transfer of a formyl group from a number of formylamino acids and formylpeptides to phenylalanine methyl ester has been studied.A fall in the yield of the transformylation reaction on passing from formyl derivatives with a free carboxy group to formyl peptides or esterified formylamino acids has been found.No transfer of an acetyl group was observed under these conditions.On the use of formyl derivatives in peptide synthesis the possibility of the occurrence of the transformylation reaction and the resulting appearance of by-products must be taken into account.Key words: peptide; enzymatic synthesis; transformylation.
- Kotlova, E. K.,Levin, E. D.,Yusupova, M. P.,Rozynov, B. V.,Stepanov, V. M.
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p. 678 - 686
(2007/10/02)
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- A facile procedure for the synthesis of N-formyl amino acid esters
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A variety of amino acid ester hydrochlorides react with triethyl orthoformate (TEOF) or trimethyl orthoformate (TMOF) to give the N-formyl amino acid ester in good yield and high optical purity.
- Chancellor,Morton
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p. 1023 - 1025
(2007/10/02)
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- SYNTHESE D'AMINOPHOSPHINEPHOSPHINITES CHIRAUX. UTILISATION EN REDUCTION ASYMETRIQUE CATALYTIQUE
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The chiral aminophosphinephosphinites ligands (AMPP) are directly synthesized from natural amino alcohols or by reduction of formyl esters of α-amino acids and PPh2Cl. Their cationic rhodium complexes have been found to be excellent catalysts for enantioselective hydrogenation of dehydroamino acids (ee ca. 86percent, yield ca. 100percent) for example.Asymmetric reduction of ketones can also be performed with the new alkyl AMPP* modified rhodium catalyst (ee 50percent).
- Karim, A.,Mortreux, A.,Petit, F.,Buono, G.,Pfeiffer, G.,Siv, C.
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- Asymmetric Syntheses via Heterocyclic Intermediates, X. - Enantioselective Synthesis of (2R)-2-Methylserines
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Aldehydes and ketones react with the lithiated bislactim ether 3 of cyclo-(L-Ala-L-Ala) with 81 to >95percent asymmetric induction (d.e. = diastereomeric excess) at C-3; (R) configuration is formed predominantly. - A model concept for the asymmetric induction is proposed. - With aldehydes or unsymmetrical ketones C-7 of the adducts 6 becomes a chiral center, too. (R) configuration is induced here with d. e. 47 - 73percent.Hydrolysis of the addition products 6 (0.25 N HCl, room temperature) gives L-Ala-OCH3 and (2R)-2-methylserine methyl esters 7.Both compounds can be separated either at the ester stage by distillation or - if 7 is thermolabile - after further hydrolysis at the amino acid stage.
- Schoellkopf, Ulrich,Groth, Ulrich,Hartwig, Wolfgang
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p. 2407 - 2418
(2007/10/02)
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