105-43-1Relevant articles and documents
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Levering,Glasebrook
, p. 1836 (1958)
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Structure and reactivity in the hydrolyses of aliphatic carboxylic acid esters and chlorides
Regan, Andrew C.,Watt, C. Ian F.
, p. 180 - 189 (2007)
For hexanoic acid and its seven isomers, relative rates have been determined for acid catalysed esterification with methanol, and compared with those for saponification of the methyl esters. A good correlation between logarithms of relative rates for the two reactions is obtained, and it is suggested that the eight isomers provide a test set of compounds in which steric effects alone act on reactivity at the acyl carbon. A full set of steric parameters (Es′ values) are presented. Rates of solvolyses of the acid chlorides- of the isomers have been determined conductometrically in 3:1 wt:wt acetonitrile water. Logarithms of relative rates show a poor correlation with Es′, and, taking into account the solvent dependence of the rates, the pattern excludes both rate-limiting formation of a tetrahedral intermediate and rate-limiting dissociation of chloride to form acylium ions. The remaining possibilities, a concerted process (ANDN?) and rapid reversible formation of a hydrate followed by rate-limiting dissociation of chloride (AN + DN?,) are considered. Copyright
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Hara et al.
, p. 2891 (1978)
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Preparative isolation and structural characterization of sucrose ester isomers from oriental tobacco
Jia, Chunxiao,Wang, Yingying,Zhu, Yonghua,Xu, Chunping,Mao, Duobin
, p. 73 - 77 (2013/05/21)
To date, the structures of the sucrose tetraester (STE) isomers, a main kind of sucrose esters (SEs) in Solanum, have not been conclusively assigned. In this study, three groups of STE isomers with the molecular weight 650, 664 and 678 (designated as STE I, STE II and STE III, respectively) have been isolated and purified from the oriental tobacco-Komotini Basma using a semi-preparative RP-HPLC method. The full characterization of the isomers in the three groups of STE were investigated for the first time by MS (HRMS, MS2) and NMR (1H, 13C, HSQC) spectroscopy combined with alkaline hydrolysis and STE derivation experiments. The STE III (a single compound) was confirmed as a known sucrose tetraester. Furthermore, the STE II was found to contain three isomers and the structures were first unambiguously established as 6-O-acetyl (2,3 or 2,4 or 3,4)-di-O-3-methylvaleryl-(4 or 3 or 2)-O-2-methylbutyryl-α-d-glucopyranosyl-β-d-fructofuranoside. Finally, the STE I was discovered to contain seven isomers and the structures were elucidated as 6-O-acetyl (2 or 3 or 4)-O-3-methylvaleryl-(3,4 or 2,4 or 2,3)-di-O-2-methylbutyryl-α-d-glucopyranosyl-β-d-fructofuranoside, 6-O-acetyl (2 or 3 or 4)-O-3-methylvaleryl-(3,4 or 2,4 or 2,3)-di-O-isovaleryl- α-d-glucopyranosyl-β-d-fructofuranoside and 6-O-acetyl (2,3 or 2,4 or 3,4)-di-O-3-methylvaleryl-(4 or 3 or 2)-O-isobutyryl-α-d-glucopyranosyl- β-d-fructofuranoside (one of the 3 isomers).
Highly stereoselective Lewis acid mediated conjugate radical additions to methyl α-D-glucopyranoside derivatives tethering an unsaturated ester moiety at C-4
Munakata, Ryosuke,Totani, Kiichiro,Takao, Ken-Ichi,Tadano, Kin-Ichi
, p. 979 - 982 (2007/10/03)
The Lewis acid mediated conjugate additions of alkyl radicals to some 4- crotonyl derivatives of methyl α-D-glucopyranoside proceeded with a high level of diastereochemical induction to provide the adducts carrying a β- chiral butanoic ester.
