114232-94-9Relevant academic research and scientific papers
Synthesis of alkyl α- and β-d-glucopyranoside-based chiral crown ethers and their application as enantioselective phase-transfer catalysts
Pálv?lgyi, ádám,Rapi, Zsolt,Ozohanics, Olivér,Tóth, Gábor,Keglevich, Gy?rgy,Bakó, Péter
, p. 1627 - 1645 (2017/11/16)
Chiral monoaza-15-crown-5-type lariat ethers annelated to alkyl 4,6-O-benzylidene-α- and β-d-glucopyranosides have been synthesized. These macrocycles generated significant asymmetric induction as phase-transfer catalysts in a few two-phase reactions. The catalytic effect of the lariat ethers with methoxy, ethoxy, and i-propoxy substituents on C-1 of the sugar unit in both α and β positions was compared. In liquid–liquid two-phase reactions, the nature and position of the substituents did not have much effect. The α-anomers were somewhat more efficient in terms of enantioselectivity than the β forms. In asymmetric Darzens condensations, in the epoxidation of trans-chalcone, in the Michael addition of β-nitrostyrene and diethyl acetamidomalonate, and in the reaction of 2-benzylidene-1,3-indandione with diethyl bromomalonate, maximum enantioselectivities of 73, 94, 78, and 72%, respectively, were obtained in presence of glucopyranoside-based lariat ethers as catalysts.
Site-selective catalysis of phenyl thionoformate transfer as a tool for regioselective deoxygenation of polyols
Sanchez-Rosello, Maria,Puchlopek, Angela L. A.,Morgan, Adam J.,Miller, Scott J.
, p. 1774 - 1782 (2008/09/18)
(Chemical Equation Presented) We report the application of peptide-embedded imidazoles as catalysts for the site-selective delivery of the phenyl thionoformate unit as a prelude to deoxygenation reactions of polyols. Methodology was developed that allows for the synthesis of thiocarbonyl derivatives based on a combination of additives that include N-alkylimidazoles and FeCl3 as co-catalysts. The use of this reagent combination leads to increased reaction rates and efficient yields relative to those of simple base-mediated reactions. In terms of controlling regioselectivity during the course of polyol modification, we found that histidine-containing peptides, in combination with FeCl3, could lead to modulation of the product distribution. Through screening of peptides and control of reaction conditions, products could be observed that reflected both the inherent preference of substrates and also reversal of inherent selectivity.
Synthesis of aminoacyl sugar derivatives and their taste characteristics. I. 2,3-Di-O-aminoacyl derivatives of alkyl D-glucopyranosides
Machinami, Tomoya,Iibuchi, Norihiro,Nomura, Takushi,Mitsumori, Takeshi,Suami, Tetsuo,Hough, Leslie
, p. 131 - 142 (2007/10/03)
Aminoacyl derivatives of methyl α- and β-D-glucopyranosides have been synthesized in order to ascertain the structural features required for the perception of a sweet taste. 2,3-Di-O-(L-aminoacyl) derivatives of methyl α-D-glucopyranoside showed a strong sweet taste (16-35x sucrose), which decreased of disappeared when either one of the two L-aminoacyl groups was absent or substituted by a D-aminoacyl group. In the case of 2,3-di-O-(L-alanyl) derivatives of methyl D-glucopyranoside, the α-anomer was very sweet (16-25x suc.) whereas the β-anomer was not sweet. The structural prerequisite for sweetness in this group of compounds proved to be the presence of L-aminoacyl groups at C-2 and C-3, and the α-configuration at C-1. Its α-isopropyl anomer showed the highest sweetness (64x suc.), hence the increased lipophilicity is also an important criterion.
