Synthetic studies on rhynchosporoside: Stereoselective synthesis of 1-O- and 2-O-α-cellotriosyl-3-deoxy-2(R)- and -2(S)-glycerol

Stereoselective Synthesis of 1- and 2-O-α-d-Cellotriosyl-3-deoxy-2(R)- and 2(S)-glycerols Related to Rhynchosporoside

“…The observation of the signals for C-l' in the 13C_ NMR spectrum at b 97.04 ppm for 28 and 97.33 for 29 supported the a-D-configuration. Glycosylation of the chiral secondary alcohols (7,8) with 9 or 10 gave inferior results under the same reaction conditions to those mentioned above. However, phenyl 4-0-acetyl-2,3,6-tri-O-benzyl-l-deoxy-l-thio-D-glucopyranoside (35, a,p-mixture) in the presence of N-bromosuccinimide and activated molcular sieves 12 )gave anomeric mixtures (36 and 38,.40 and 42) with the 1 : 1 ratios in 70.0 and 54.1 % yields, respectively.…”

Synthetic Studies on Derivatives of 5-O-β-d-Galactofuranosyl-d-galactofuranose

“…Excess sodium hydride was decomposed by methariol, and the reaction mixture was diluted with chloroform, washed with water, dried over magnesium sulfate, and finally evaporated. 5-0-f3-n-Galactofuranosyl-f3-n-galactofuranose (1). A solution of 13 (2.0 g) in methanol (30 ml) containing a catalytic amount of sodium methoxide was stirred for 1hr at room temperature.…”

“…Recently, the structure of the carbohydrate moiety was revised by Beir et al 3 ) to 5-0-{J-D-galactofuranosyl-{J-D-galactofuranose (1), and the gross structure was fully' elucidated by Macko et al 4 ) for HS-toxinsA, Band C (2) by spectroscopic means. Macko also isolated such biosynthetically related intermediates as mono.…”

Synthetic studies on glycosidic phytotoxins. Part V Stereoselective synthesis of 1- and 2-O-.ALPHA.-D-cellotriosyl-3-deoxy-2(R)- and 2(S)-glycerols related to rhynchosporoside.

“…After debenzylation, the products (59, 60) were identified using the authentic samples1} by specrrometric analysis and chromatographic comparison, and from the physicochemical data. Glycosylation of the chiral alcohols (5,6,7,8) The mixture was stirred for 16hr at 20°C under argon.…”