Methylation of methyl α-d-hexopyranosides with diazo-methane in the presence of a small amount of water
作者:Yuko Inoue、Kinzo Nagasawa
DOI:10.1016/0008-6215(87)80024-1
日期:1987.11
Abstract The long-time reduction of methylα-d -gluco-, α-d -manno-, and α-d -galactopyranosides with excess diazomethane-diethyl ether at 25° in the presence of water gave all partially methylated methylα-d -hexopyranosides which differ in number and position of methyl substitution. The presence of electrolytes, such as potassium or sodium phosphate, in the reaction medium enhanced the degree of methylation
Regioselective methylation of methyl glycopyranosides with diazomethane in the presence of transition-metal chlorides and of boric acid
作者:Evgeny V. Evtushenko
DOI:10.1016/s0008-6215(99)00044-0
日期:1999.3
Abstract Partial methylation of the methyl pyranosides of a number of pentoses, hexoses, 6-deoxyhexoses, methyl uronates and their methyl ethers with diazomethane in the presence of transition-metal chlorides and boric acid was studied. It was found for methyl glycosides of pentoses and 6-deoxyhexoses that tin(II), antimony(III), and titanium(IV) chlorides as well as boric acid promoted substitution
Exciton Chirality Method in Vibrational Circular Dichroism
作者:Tohru Taniguchi、Kenji Monde
DOI:10.1021/ja3001584
日期:2012.2.29
yields a strong vibrationalcirculardichroism couplet whose sign reflects the absolute configuration of the molecule. We present a method to determine absolute configuration of a chiral molecule based on this couplet without need of theoretical calculation. Not only can this method analyze various molecules whose absolute configuration is difficult to determine by other spectroscopic methods, but also it
Rapid access to rare natural pyranosides using 1,2-diacetal protected intermediates
作者:Steven V. Ley、Dafydd R. Owen、Kieron E. Wesson
DOI:10.1039/a705360f
日期:——
The synthesis of six rare methylpyranosides from common manno- and galacto-pyranoside starting materials has been achieved by the expedient use of 1,2-diacetal protecting group methodology highlighting its compatibility with a number of other common synthetic procedures.
Gas-liquid chromatography-mass spectrometry of methylated and deuteriomethylated per-O-acetyl-aldononitriles from D-mannose
作者:Fred R. Seymour、Ronald D. Plattner、Morey E. Slodki
DOI:10.1016/s0008-6215(00)84162-2
日期:1975.11
D-mannopyranose were separated by gas-liquidchromatography, and analyzed by mass spectrometry. Through introduction of deuteriomethyl ether groups, various fragmentions constituting the mass spectra were identified and related to the parent methylated sugar structures. Also identified were several characteristic series of fragment ions that are common to two or more methylated D-mannopyranosides. As expected