The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Seth B Herzon - One of the best experts on this subject based on the ideXlab platform.
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general method for the synthesis of α or β deoxyaminoglycosides bearing basic nitrogen
Journal of the American Chemical Society, 2021Co-Authors: Kevin M Hoang, Nicholas R Lees, Seth B HerzonAbstract:The introduction of glycosides bearing basic nitrogen is challenging using conventional Lewis acid-promoted pathways owing to competitive coordination of the amine to the Lewis acid promoter. Additionally, because many aminoglycosides lack a C2 substituent, diastereomeric mixtures of O-glycosides are often produced. Herein, we present a method for the synthesis of α- or β- 2,3,6-trideoxy-3-amino- and 2,4,6-trideoxy-4-amino O-glycosides from a common precursor. Our strategy proceeds by the reductive lithiation of thiophenyl glycoside donors and trapping of the resulting anomeric anions with 2-methyltetrahydropyranyl peroxides. We apply this strategy to the synthesis of α- and β-forosamine, pyrrolosamine, acosamine, and ristosamine derivatives using primary and secondary peroxides as electrophiles. α-Linked products are obtained in 60-96% yield and with >50:1 selectivity. β-Linked products are obtained in 45-94% yield and with 1.7->50:1 stereoselectivity. Contrary to donors bearing an equatorial amine substituent, donors bearing an axial amine substituent favored β-products at low temperatures. This work establishes a general strategy to synthesize O-glycosides bearing a basic nitrogen.
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synthesis of 1 3 amino alcohols 1 3 diols amines and carboxylic acids from terminal alkynes
ChemInform, 2015Co-Authors: Mingshuo Zeng, Seth B HerzonAbstract:Anti-Markovnikov functionalization reactions of terminal alkynes and propargylic amines efficiently lead to 1,3-diol products and 1,3-amino alcohols, respectively, without loss of stereochemistry.
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synthesis of 1 3 amino alcohols 1 3 diols amines and carboxylic acids from terminal alkynes
Journal of Organic Chemistry, 2015Co-Authors: Mingshuo Zeng, Seth B HerzonAbstract:The half-sandwich ruthenium complexes 1–3 activate terminal alkynes toward anti-Markovnikov hydration and reductive hydration under mild conditions. These reactions are believed to proceed via addition of water to metal vinylidene intermediates (4). The functionalization of propargylic alcohols by metal vinylidene pathways is challenging owing to decomposition of the starting material and catalytic intermediates. Here we show that catalyst 2 can be employed to convert propargylic alcohols to 1,3-diols in high yield and with retention of stereochemistry at the propargylic position. The method is also amenable to propargylic amine derivatives, thereby establishing a route to enantioenriched 1,3-amino alcohol products. We also report the development of formal anti-Markovnikov reductive amination and oxidative hydration reactions to access linear amines and carboxylic acids, respectively, from terminal alkynes. This chemistry expands the scope of products that can be prepared from terminal alkynes by practica...
Rosario M Diaz - One of the best experts on this subject based on the ideXlab platform.
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samarium promoted asymmetric aldol tishchenko reaction synthesis of amino acid derived 4 amino 1 3 diols
ChemInform, 2012Co-Authors: Humberto Rodriguezsolla, Carmen Concellon, Paula Tuya, Santiago Garciagranda, Rosario M DiazAbstract:Enantiopure title compounds (V) are obtained after reduction of aldol—Tishchenko adducts formed with moderate diastereoselectivity from chiral amino ketones (I) and aliphatic aldehydes.
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samarium promoted asymmetric aldol tishchenko reaction synthesis of amino acid derived 4 amino 1 3 diols
Advanced Synthesis & Catalysis, 2012Co-Authors: Humberto Rodriguezsolla, Carmen Concellon, Paula Tuya, Santiago Garciagranda, Rosario M DiazAbstract:A samarium-mediated novel synthesis of enantiopure 4-amino-1,3-diols is carried out through a samarium-promoted aldol–Tishchenko reaction starting from chiral α′-amino-α-chloro ketones (derived from natural α-amino acids) and aldehydes. The process takes place with moderate levels of stereoselectivity and in high yields. A mechanism is proposed to explain these results while the absolute configuration and structure of the aldol–Tishchenko adducts were established by X-ray analysis. This method has also been utilized for the synthesis of enigmols, 1-deoxysphingoid base analogues.
Pinaki Talukdar - One of the best experts on this subject based on the ideXlab platform.
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a 1 3 amino group migration route to form acrylamidines
ChemInform, 2014Co-Authors: Dinesh Pratapsinh Chauhan, Sreejith Jayasree Varma, Arjun Vijeta, Pallavi Banerjee, Pinaki TalukdarAbstract:A novel route for the synthesis of acrylamidines by Cu-catalyzed addition of tosylazide to 1-aminopropines and subsequent intramolecular addition of nucleophiles to ketenimines with 1,3-amino group migration is presented.
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a 1 3 amino group migration route to form acrylamidines
Chemical Communications, 2014Co-Authors: Dinesh Pratapsinh Chauhan, Sreejith Jayasree Varma, Arjun Vijeta, Pallavi Banerjee, Pinaki TalukdarAbstract:A novel 1,3-amino group migration strategy for the synthesis of acrylamidines is presented. Cu(I) catalyzed reaction of N,N-disubstituted propargylamine with tosylazide generates a highly reactive ketenimine intermediate which is trapped by a tethered amino group leading to the rearrangement reaction.
Estrella Álvarez - One of the best experts on this subject based on the ideXlab platform.
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surface tension of aqueous binary mixtures of 1 amino 2 propanol and 3 amino 1 propanol and aqueous ternary mixtures of these amines with diethanolamine triethanolamine and 2 amino 2 methyl 1 propanol from 298 15 to 323 15 k
Journal of Chemical & Engineering Data, 2003Co-Authors: Estrella Álvarez, José M. Navaza, Angeles Cancela, Rocio Maceiras, Ruben TaboasAbstract:The surface tension of aqueous binary solutions of 1-amino-2-propanol and 3-Amino-1-propanol and aqueous ternary solutions of these amines with diethanolamine, triethanolamine, and 2-amino-2-methyl-1-propanol was measured at temperatures from 298.15 K to 323.15 K. For binary mixtures, the concentration range was 0−100 mass percent alkanolamine, and for ternary mixtures, the concentration range for each amine was 0−50 mass percent. The experimental values for binary mixtures were correlated with mole fraction by an empirical equation (the maximum deviation was in both cases always less than 0.2%).
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surface tension of binary mixtures of water monoethanolamine and water 2 amino 2 methyl 1 propanol and tertiary mixtures of these amines with water from 25 c to 50 c
Journal of Chemical & Engineering Data, 1997Co-Authors: Gonzalo Vazquez, Estrella Álvarez, José M. Navaza, And Raquel Rendo, Eva RomeroAbstract:The surface tension of aqueous solutions of monoethanolamine, 2-amino-2-methyl-1-propanol, and monoethanolamine + 2-amino-2-methyl-1-propanol was measured at temperatures from 25 °C to 50 °C. The concentration ranges were 0−100 mass % monoethanolamine and 2-amino-2-methyl-1-propanol, and for tertiary mixtures 50 mass % total amine concentration (the concentration range for each amine was 0−50 mass %). The experimental values were correlated with temperature and mole fraction. The maximum deviation was in both cases always less than 0.5%.
Humberto Rodriguezsolla - One of the best experts on this subject based on the ideXlab platform.
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samarium promoted asymmetric aldol tishchenko reaction synthesis of amino acid derived 4 amino 1 3 diols
ChemInform, 2012Co-Authors: Humberto Rodriguezsolla, Carmen Concellon, Paula Tuya, Santiago Garciagranda, Rosario M DiazAbstract:Enantiopure title compounds (V) are obtained after reduction of aldol—Tishchenko adducts formed with moderate diastereoselectivity from chiral amino ketones (I) and aliphatic aldehydes.
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samarium promoted asymmetric aldol tishchenko reaction synthesis of amino acid derived 4 amino 1 3 diols
Advanced Synthesis & Catalysis, 2012Co-Authors: Humberto Rodriguezsolla, Carmen Concellon, Paula Tuya, Santiago Garciagranda, Rosario M DiazAbstract:A samarium-mediated novel synthesis of enantiopure 4-amino-1,3-diols is carried out through a samarium-promoted aldol–Tishchenko reaction starting from chiral α′-amino-α-chloro ketones (derived from natural α-amino acids) and aldehydes. The process takes place with moderate levels of stereoselectivity and in high yields. A mechanism is proposed to explain these results while the absolute configuration and structure of the aldol–Tishchenko adducts were established by X-ray analysis. This method has also been utilized for the synthesis of enigmols, 1-deoxysphingoid base analogues.