65222-57-3Relevant academic research and scientific papers
Regioselective benzoylation of glycopyranosides by benzoic anhydride in the presence of Cu(CF3COO)2
Evtushenko, Evgeny V.
, p. 111 - 119 (2012/11/07)
Benzoylation of methyl and benzyl glycopyranosides by benzoic anhydride in acetonitrile in the presence of copper(II) trifluoroacetate as a promoter has given monobenzoates with a good yield and high regioselectivity. The composition of monobenzoates depended both on a configuration of hydroxyl groups and on a configuration of aglycone. The simple syntheses of the monobenzoates of some glycosides are offered.
Regioselective benzoylation of glycopyranosides by benzoyl chloride in the presence of MoO2(acac)2
Evtushenko
experimental part, p. 369 - 378 (2012/06/04)
Benzoylation of methyl and benzyl glycopyranosides by benzoyl chloride in the presence of MoO2(acac)2 as a catalyst resulted in 3-benzoates with good yield and high regioselectivity. Simple synthesis of the monobenzoates of some glyc
A convenient synthesis of furanose-free D-fucose per-O-acetates and a precursor for anthrose
Hou, Shujie,Kovac, Pavol
experimental part, p. 1947 - 1952 (2009/04/04)
Methyl 3,4-O-isopropylidene-α- or β-D-galactopyranoside was iodinated with triiodoimidazole in the presence of triphenylphosphane and the corresponding 6-deoxy-6-iodo derivatives 5 or 6, respectively, were converted to furanose-free 1,2,3,4-tetra-O-acetyl-α,β-D-fucopyranose. A key intermediate for chemical synthesis of anthrose, a constituent of the tetrasaccharide of major glycoprotein of Bacillus anthracis exosporium, 1-O-acetyl-4-azido-2-O-benzoyl-3-O-benzyl-4,6-dideoxy-α, β-D-glucopyranose, was synthesized from 5 or 6 in 7 steps. The latter was readily converted into the corresponding 1-O-trichloroacetimidate. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
Studies of the Mechanistic Diversity of Sodium Cyanoborohydride Reduction of Tosylhydrazones
Miller, Vaughn P.,Yang, Ding-yah,Weigel, Theresa M.,Han, Oksoo,Liu, Hung-wen
, p. 4175 - 4188 (2007/10/02)
Reduction of tosylhydrazone derivatives of ketones and aldehydes with sodium cyanoborohydride in acidic medium is a mild, albeit versatile, deoxygenation reaction.The reaction mechanism has been proposed to proceed via either a direct hydride attack route or a tautomerization-then-reduction route.By using a mild reduction procedure (NaBH3CN, THF-MeOH, 0 deg C), it has been possible to stop the deoxygenation halfway and isolate the nascent tosylhydrazine product.Characterization of the resulting hydrazine to define the origin of the hydrogen being delivered to theformer carbonyl carbon has allowed us to unambiguously distinguish between these two possible mechanisms.Studies of reduction of tosylhydrazones derived from conjugated and saturated ketones confirmed earlier speculation that these reductions occur through a direct hydride attack mechanism.The reduction of para-substituted methyl phenyl ketone tosylhydrazones revealed a competition between these two mechanisms.Substrates bearing electron-donating substituents prefer to direct hydride attack pathway, while those with electron-withdrawing substituents favor an initial tautomerization prior to reduction.Sugar and hydroxyl ketone tosylhydrazones are also reduced by competing mechanisms.The mechanistic diversity in those cases may be attributed to the inductive effects compelled by the α substituents and the conformational constraints imposed by the ring structure.The mechanistic insights gained from these studies indicate that the direct hydride attack mechanism is the main reaction pathway due to the propensity of NaBH3CN to selectively attack the iminium ion.The tautomerization-then-reduction mechanism prevails only when the tautomerization of hydrazon to azohydrazine is facilitated.
