16782-23-3Relevant academic research and scientific papers
Enantioselective Addition of α-Nitroesters to Alkynes
Davison, Ryan T.,Parker, Patrick D.,Hou, Xintong,Chung, Crystal P.,Augustine, Sara A.,Dong, Vy M.
supporting information, p. 4599 - 4603 (2021/01/18)
By using Rh–H catalysis, we couple α-nitroesters and alkynes to prepare α-amino-acid precursors. This atom-economical strategy generates two contiguous stereocenters, with high enantio- and diastereocontrol. In this transformation, the alkyne undergoes isomerization to generate a RhIII–π-allyl electrophile, which is trapped by an α-nitroester nucleophile. A subsequent reduction with In powder transforms the allylic α-nitroesters to the corresponding α,α-disubstituted α-amino esters.
Design, synthesis, and evaluation of a novel macrocyclic anti-EV71 agent
Li, Peng,Wu, Siqi,Xiao, Tianyichen,Li, Yunlong,Su, Zhiming,Wei, Wei,Hao, Fei,Hu, Guoping,Lin, Fusen,Chen, Xinsheng,Gu, Zhengxian,Lin, Tianwei,He, Haiying,Li, Jian,Chen, Shuhui
, (2020/05/18)
We describe here the design, synthesis, and evaluation of a macrocyclic peptidomimetic as a potent agent targeting enterovirus A71 (EV71). The compound has a 15-membered macrocyclic ring in a defined conformation. Yamaguchi esterification reaction was used to close the 15-membered macrocycle instead of the typical Ru-catalyzed ring-closing olefin metathesis reaction. The crystallographic characterization of the complex between this compound and its target, 3C protease from EV71, validated the design and paved the way for the generation of a new series of anti-EV71 agents.
Synthesis of unnatural α-amino esters using ethyl nitroacetate and condensation or cycloaddition reactions
Gagnot, Glwadys,Hervin, Vincent,Coutant, Eloi P.,Desmons, Sarah,Baatallah, Racha,Monnot, Victor,Janin, Yves L.
, p. 2846 - 2852 (2018/11/27)
We report here on the use of ethyl nitroacetate as a glycine template to produce α-amino esters. This started with a study of its condensation with various arylacetals to give ethyl 3-aryl-2-nitroacrylates followed by a reduction (NaBH4 and then zinc/HCl) into α-amino esters. The scope of this method was explored as well as an alternative with arylacylals instead. We also focused on various [2 + 3] cycloadditions, one leading to a spiroacetal, which led to the undesired ethyl 5-(benzamidomethyl)isoxazole-3-carboxylate. The addition of ethyl nitroacetate on a 5-methylene-4,5-dihydrooxazole using cerium(IV) ammonium nitrate was also explored and the synthesis of other oxazole-bearing α-amino esters was achieved using gold(I) chemistry.
One-pot multifunctional catalysis with NNN-Pincer Zr-MOF: Zr base catalyzed condensation with Rh-catalyzed hydrogenation
Rasero-Almansa, Antonia M.,Corma, Avelino,Iglesias, Marta,Sánchez, Félix
, p. 3092 - 3100 (2013/10/21)
We describe the postsynthetic modification of Zr-based metal organic frameworks (MOFs) containing chiral NNN-pincer ligands based on aminopyridineimines, as well as the subsequent formation of (NNN)-M-Zr-MOF complexes (M=Rh, Ir). With these new multifunct
Ethynyl-1,2-benziodoxol-3(1H)-one (EBX): An exceptional reagent for the ethynylation of keto, cyano, and nitro esters
Gonzalez, Davinia Fernandez,Brand, Jonathan P.,Waser, Jerome
supporting information; experimental part, p. 9457 - 9461 (2010/10/03)
Hot alkyne! The in situ generation of ethynyl-1,2-benziodoxol-3(1H)-one (EBX) from a silyl-protected reagent by using TBAF is reported. EBX displayed exceptional acetylene transfer ability onto stabilized enolates (see scheme), even at -78 □°C. The mild reaction conditions allowed the first ethynylation reactions of linear keto, cyano, and nitro esters in high yields to give all-carbon quaternary centers or non-natural amino acids after selective reduction of the nitro group.
Development of pharmaceutical drugs, drug intermediates and ingredients by using direct organo-click reactions
Ramachary, Dhevalapally B.,Kishor, Mamillapalli,Reddy, Y. Vijayendar
supporting information; experimental part, p. 975 - 993 (2009/04/11)
Here we report on our studies of the use of combinations of amino acids, amines, K2CO3 or Cs2CO3 and CuSO4/Cu for catalysing green cascade reactions. We aimed to prepare the highly reactive and substituted olefin species 7 and 8, under very mild and environmentally friendly conditions, thus giving the hydrogenated products 10 and 12 through the action of Hantzsch ester (4) by self-catalysis through decreasing the HOMO-LUMO energy gaps between olefins 7/8 and Hantzsch ester (4) through biomimetic reductions. Highly useful compounds 10 to 14 were assembled from simple substrates such as aldehydes 1, ketones 2, CH acids 3, Hantzsch ester (4) and alkyl halides 5 by diversity-oriented green synthesis involving cascade olefination/hydrogenation (O/H), olefination/hydrogenation/alkylation (O/H/A) and hydrogenation/olefination/hydrogenation (H/O/H) reaction sequences in one-pot fashion with stereospecific organo- and organo-/metal-carbonate catalysis. Highly functionalized diverse compounds such as 10 to 14 are biologically active products and have found wide applications as pharmaceutical drugs, drug intermediates and drug ingredients. For the first time in organocatalysis, we report the O/H/A/TE reaction to furnish high yields of transesterification products 11 by simply mixing the reactants under proline/K2CO3 catalysis conditions. Additionally, a novel organocatalytic H/O/H reaction sequence for the synthesis of alkyl-substituted aromatics has been developed. Furthermore, for the first time we have developed organocatalysed cascade olefination/hydrogenation/hydrolysis (O/H/H) reactions to furnish highly useful materials such as 2-oxochroman-3-carboxylic acid (14kc) and 2-amino-4H-chromene-3-carbonitrile (14kj) in good yields. Experimentally simple and environmentally friendly organocatalytic two-carbon homologation through cascade O/H/H reactions of aldehydes 1, Meldrum's acid (3c), Hantzsch ester (4) and acetic acid/triethylamine in ethanol has been demonstrated. Additionally, we have developed a green synthesis of the highly substituted 1,2,3-triazole 17 from simple substrates through a two-step combination of olefination/hydrogenation/alkylation and Huisgen cycloaddition reaction sequences under stereospecific organocopper catalysis conditions. In this paper we have found strong support for our hypothesis that, "decreasing the HOMO-LUMO energy gap between olefins 7/8 and Hantzsch ester (4) will drive the biomimetic hydrogenation reaction by self-catalysis". This self-catalysis was further confirmed with many varieties of examples. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
Transforming natural amino acids into α-alkyl-substituted amino acids with the help of the HOF·CH3CN complex
Harel, Tal,Rozen, Shlomo
, p. 6500 - 6503 (2008/02/10)
(Chemical Equation Presented) α-Alkyl amino acids can be efficiently prepared in high yields from the respective amino acids themselves. The key step is the oxidation of the amine function to create the corresponding α-nitro acid in a fast and very high yield reaction followed by phase-transfer alkylation and finally reduction to the desired α-alkyl amino acid. Several such acids containing aromatic rings or additional carboxylic groups and acids with steric hindrance at the α-position are suitable substrates. Several alkyl halides were examined as alkylating agents.
Towards organo-click reactions: Development of pharmaceutical ingredients by using direct organocatalytic bio-mimetic reductions
Ramachary, Dhevalapally B.,Reddy, G. Babul
, p. 4463 - 4468 (2008/09/19)
Economic and environmentally friendly bio-mimetic one-pot three and four-component Knoevenagel-hydrogenation (K-H), five-component Knoevenagel-hydrogenation-alkylation (K-H-A) and six-component Knoevenagel-hydrogenation-alkylation-Huisgen cycloaddition (K-H-A-HC) reactions of aldehydes, CH-acids, o-phenylenediamine, alkyl halides and azides using proline, proline-metal carbonate and proline-metal carbonate-Cu I-catalysis, respectively have been developed. Many of K-H and K-H-A compounds have direct application in pharmaceutical chemistry. The Royal Society of Chemistry.
A novel and green protocol for two-carbon homologation: A direct amino acid/K2CO3-catalyzed four-component reaction of aldehydes, active methylenes, Hantzsch esters and alkyl halides
Ramachary, Dhevalapally B.,Kishor,Ramakumar
, p. 651 - 656 (2007/10/03)
A novel and green approach for the two-carbon homologation of aldehydes using amino acid catalysis has been developed and further extended to the generation of pharmaceutically active cyano-esters via four-component reactions in one-pot.
Oxidation potential as a measure of the reactivity of anionic nucleophiles. Behaviour of different classes of nucleophiles
Niyazymbetov, Murat E.,Rongfeng, Zhou,Evans, Dennis H.
, p. 1957 - 1962 (2007/10/03)
Anodic peak potentials for 42 anionic nucleophiles are reported along with the rate constants for the reactions of the anions with benzyl chloride.By comparing these rate constants with those of the reactions of outer-sphere electron-transfer reagents (radical anions), it has been demonstrated that the reactions of the anions with benzyl chloride are typical single-step SN2 reactions as opposed to a two-step process comprising dissociative single electron transfer (SET) to benzyl chloride followed by radical combination.The data suggest that very electron-rich nucleophilic anions with potentials of -1.5 to -2.2 V (and more negative) with respect to the ferrocenium/ferrocene couple might participate in a SET reaction.The 42 anions studied included representatives of four classes of nucleophiles, viz. sulfur-, carbon-, oxygen- and nitrogen-centred anions.The previously observed correlation of rate constants and anodic peak potential was again found for these anions with the most reactive species having the most negative peak potentials.Correlations by class indicate that the sensitivity of rate constants to changes in peak potential is greatest (and equivalent) for the sulfur-, carbon- and oxygen-anions and for representatives with the same peak potential, the rate constants by class follow the order sulfur > carbon > oxygen.The nitrogen nucleophiles show a significantly lower sensitivity of rate constant to changes in peak potential than do the other three classes.
