Direct one-pot conversion of acylated carbohydrates into their alkylated derivatives under heterogeneous reaction conditions using solid NaOH and a phase transfer catalyst

1H and 13C NMR data of methyl tetra‐O‐benzoyl‐D‐pyranosides in acetone‐d6

“…1 H NMR spectra of all compounds have previously been reported in CDCl 3 at variable field strengths. [7 -14] For most protons, variance in shift values between the current study and those reported previously in CDCl 3 were only of minor magnitude (<0.1 ppm). However, for methyl 2,3,4,6-tetra-O-benzoyl-β-D-glucopyranoside (4) chemical shifts for H-1, H-3 and H-5 were increased by ca.…”

“…Alternatively, the anomeric carbon can be subjected to various reaction such as halogenation, arylations [1] or allylations. [2] Other possible reactions includes conversion to carbohydrate ethers, [3] and oxidative cleavage. [4] If required the remaining ester moieties can be readily removed under mild conditions.…”

Tandem Epoxidation‐Alcoholysis or Epoxidation‐Hydrolysis of Glycals Catalyzed by Titanium(IV) Isopropoxide or Venturello’s Phosphotungstate Complex

“…All other glycals and the glycosides used as nucleophiles were synthesized according to known literature procedures: tri-O-benzyl-d-glucal, [17] 3,4-di-O-benzyl-d-glucal, [18,19] tri-O-methyl-d-glucal, [20] 6-O-TBDPS-d-glucal, [18] tri-O-TBDMS-d-glucal, [19] tri-O-acetyl-d-galactal, [22] tri-O-benzyld-galactal, [18] di-O-benzyl-d-xylal, [21,23] 2,3,4-tri-O-benzyl-dmethylglucoside, [24] 2,3,4,6-tetra-O-benzyl-d-glucoside.…”

Total synthesis of an antigenic heptasaccharide motif found in the cell-wall lipooligosaccharide of Mycobacterium gordonae strain 989

“…1 Structure of heptasaccharide motif of the glycolipid found in the cell-wall of M. gordonae strain 989 of a combination of N-iodosuccinimide (NIS) and trimethylsilyl trifluoromethanesulfonate (TMSOTf) [42,43] furnished the disaccharide derivative 12 in 81% yield. Conversion of the acetyl group to the benzyl group of compound 12 in one step [39] using benzyl bromide and sodium hydroxide furnished compound 13 in 84% yield. Oxidative removal of 4-methoxybenzyl group using dichloro-dicyano-benzoquinone (DDQ) [44] in a bi-phasic reaction condition resulted in the formation of disaccharide acceptor 14 in 86% yield.…”

“…Tin mediated [37] selective 4-methoxybenzylation of ethyl 4-O-benzyl-1-thio-α-L-rhamnopyranoside (6) [38] followed by acetylation furnished compound 7 in excellent yield. Compound 8 was also prepared from compound 6 in excellent yield following the similar reaction sequences except a base mediated methylation [39] in stead of acetylation. Removal of isopropylidene group from ethyl 3,4-O-isopropylidene-2-O-methyl-1-thio-β-L-fucopyranoside (9) [40] followed by tin mediated selective benzylation [37] and acetylation furnished compound 10 in excellent yield.…”