- Simplified Procedures for 1-Amino-2-propyne and Some Homologues
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1-Amino-2-propyne has been obtained in good yields by successive solvolysis of propargyl bromide in liquid ammonia, metalation of the dissolved amine with sodamide, and hydrolysis after complete removal of the ammonia by evaporation. Some homologues, RC≡CCH2NH2, have been obtained in fair yields by addition of alkyl bromides to the solution of the sodium derivative of 1-amino-2-propyne.
- Zwikker, Jan W.,Brandsma, Lambert,Verkruijsse, Hermann D.
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- Design and Synthesis of Oleanolic Acid Trimers to Enhance Inhibition of Influenza Virus Entry
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Influenza is a major threat to millions of people worldwide. Entry inhibitors are of particular interest for the development of novel therapeutic strategies for influenza. We have previously discovered oleanolic acid (OA) to be a mild influenza hemagglutinin (HA) inhibitor. In this work, inspired by the 3D structure of HA as a homotrimeric receptor, we designed and synthesized 15 OA trimers with different linkers and central region via the copper-catalyzed azide-alkyne cycloaddition reaction. All of the OA trimers were evaluated for their antiviral activities in vitro, and 12c, 12e, 13c, and 13d were observed to exhibit robust potency (IC50 in the submicromolar range) against influenza A/WSN/33 (H1N1) virus that was stronger than that observed with oseltamivir. In addition, these compounds also displayed strong biological activity against A/Hong Kong/4801/2014 and B/Sichuan/531/2018 (BV). The results of hemagglutination inhibition assays and surface plasmon resonance binding assays suggest that these OA trimers may interrupt the interaction between the HA protein of influenza virus and the host cell sialic acid receptor, thus blocking viral entry. These findings highlight the utility of multivalent OA conjugates to enhance the ligand-target interactions in anti-influenza virus drug design and are also helpful for studying antiviral drugs derived from natural products.
- Huang, Boxuan,Li, Weijia,Mu, Yu,Shao, Liang,Su, Yangqing,Sun, Mengsi,Xu, Huan,Yang, Fan,Yu, Fei,Zhang, Jihong,Zhang, Yuan
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p. 1759 - 1765
(2021/11/18)
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- Construction of the Oxazolidinone Framework from Propargylamine and CO2 in Air at Ambient Temperature: Catalytic Effect of a Gold Complex Featuring an L2/Z-Type Ligand
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The metal-catalyzed carboxylation of propargylamines with aerial CO2 at room temperature to form 5-methyleneoxazolidin-2-one derivatives has been developed. In this reaction, the catalyst [Au(dpbF)]X featuring a Z-type ligand gave the best results, presumably due to the σ-acceptance of the borane atom.
- Inagaki, Fuyuhiko,Maeda, Kakeru,Nakazawa, Kenta,Mukai, Chisato
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p. 2972 - 2976
(2018/06/27)
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- O -Phthalaldehyde catalyzed hydrolysis of organophosphinic amides and other P(O)-NH containing compounds
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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.
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supporting information
p. 8667 - 8670
(2017/08/10)
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- Palladium(II)-Catalyzed Regioselective syn-Hydroarylation of Disubstituted Alkynes Using a Removable Directing Group
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A palladium(II)-catalyzed regioselective syn-hydroarylation reaction of homopropargyl amines has been developed, wherein selectivity is controlled by a cleavable bidentate directing group. Under the optimized reaction conditions, both dialkyl and alkylaryl alkyne substrates were found to undergo hydroarylation with high selectivity. The products of this reaction contain a 4,4-disubstituted homoallylic amine motif that is commonly seen in drug molecules and other bioactive compounds.
- Liu, Zhen,Derosa, Joseph,Engle, Keary M.
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supporting information
p. 13076 - 13081
(2016/10/13)
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- Cu(I)-catalyzed synthesis of dihydropyrimidin-4-ones toward the preparation of β- And β3-amino acid analogues
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A copper(I)-catalyzed synthesis of substituted dihydropyrimidin-4-ones from propargyl amides via the formation of ketenimine intermediate has been successfully developed; the synthesis afforded good isolated yields (80-95%). The mild reaction conditions at room temperature allow the reaction to proceed to completion in a few hours without altering the stereochemistry. Further, by involving a variety of reactive nucleophiles, the obtained substituted dihydropyrimidin-4-ones were elegantly transformed into the corresponding β- and β3-amino acid analogues.
- Rajagopal, Basker,Chen, Ying-Yu,Chen, Chun-Chi,Liu, Xuan-Yu,Wang, Huei-Ren,Lin, Po-Chiao
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supporting information
p. 1254 - 1264
(2014/03/21)
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- A convenient approach to synthesizing peptide C-terminal N-alkyl amides
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Peptide C-terminal N-alkyl amides have gained more attention over the past decade due to their biological properties, including improved pharmacokinetic and pharmacodynamic profiles. However, the synthesis of this type of peptide on solid phase by current available methods can be challenging. Here we report a convenient method to synthesize peptide C-terminal N-alkyl amides using the well-known Fukuyama N-alkylation reaction on a standard resin commonly used for the synthesis of peptide C-terminal primary amides, the peptide amide linker-polyethylene glycol-polystyrene (PAL-PEG-PS) resin. The alkylation and oNBS deprotection were conducted under basic conditions and were therefore compatible with this acid labile resin. The alkylation reaction was very efficient on this resin with a number of different alkyl iodides or bromides, and the synthesis of model enkephalin N-alkyl amide analogs using this method gave consistently high yields and purities, demonstrating the applicability of this methodology. The synthesis of N-alkyl amides was more difficult on a Rink amide resin, especially the coupling of the first amino acid to the N-alkyl amine, resulting in lower yields for loading the first amino acid onto the resin. This method can be widely applied in the synthesis of peptide N-alkyl amides.
- Fang, Wei-Jie,Yakovleva, Tatyana,Aldrich, Jane V.
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p. 715 - 722
(2013/05/09)
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- 2-aminobenzoxazole derivatives and combinatorial libraries thereof
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The present invention relates to novel 2-aminobenzoxazole derivative compounds of the following formula: wherein R1 to R4 and Z have the meanings provided herein. The invention further relates to combinatorial libraries containing two or more such compounds, as well as methods of preparing 2-aminobenzoxazole derivative compounds.
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- Optimized procedures for one-pot conversion of alkyl bromides into amines via the Staudinger reaction
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New optimized procedures for transforming primary and secondary alkyl bromides into the corresponding primary amine salts have been elaborated. Essential modifications of azidation and deprotection of intermediate triethoxyphosphine alkylimides resulted in substantial improvement of the overall yields. Conversion of ammonium tosylates and hydrochlorides into free amines in a nonaqueous medium is described.
- Koziara,Zwierzak
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p. 1063 - 1065
(2007/10/02)
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- Catalysis by Cucurbituril. The Significance of Bound-Substrate Destabilization for Induced Triazole Formation
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A mechanistic investigation is described for the cycloaddition induced between RNH2+CH2CCH and RNH2+CH2CH2N3 (R = H, t-Bu) consequent to encapsulationby the polycyclic molecular receptor cucrbituril (C36H36N24O12).The reaction is shown to be substantially accelerated (ca. 105-fold), and the kinetic characteristics of catalytic saturation behavior, substrate inhibition, and slow product release are documented.For substrates with R = t-Bu a rotaxane product results, and inhibition kinetics with NH3+CH2CH2C(CH3)3 are also examined.A rate enhancementattributed to bound-substrate destabilization is detected.The significance of this effect and its connection with the phenomenon of nonproductive binding in catalytic systems are discussed.
- Mock, William L.,Irra, Ted A.,Wepsiec, James P.,Adhya, Mita
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p. 5302 - 5308
(2007/10/02)
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- N-Heterocyclic-9-xanthenylamines
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The compounds are N-piperidinyl and pyrrolidinyl-9-xanthenylamines which are inhibitors of gastric acid secretion.
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