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

Synthesis and Reactions of 1,4‐Anhydrogalactopyranose and 1,4‐Anhydroarabinose – Steric and Electronic Limitations

“…Reaction with allylic alcohol and subsequent allylation gave allyl galactofuranoside 5b with better stereoselectivity (Entry 2). Galactofuranoside 5b is useful for the synthesis of galactofuranosyl galactofuranose units as reported by Ogawa and co-workers [7]. Pentenyl galactofuranoside 5c was prepared, when pent-4-en-1-ol was employed (Entry 3).…”

Synthetic Studies on Rhynchosporoside and Related Substances

“…The filtrate was evaporated in vacuo to give a quantitive yield of 14, Rf 0.44 in 19: 1 toluene---ethyl acetate. 1,3,4,. A mixture of 14 (4.6 g), 15 (1.1 g), tetrabutylammonium chloride (2.3 g) and N,N-· diisopropylethylamine (1.2 g) in dichloroethane (50 ml) was stirred for 16 hr at 85", 95°C under argon.…”

“…The reaction mixture was filtered through celite, and then the filtrate was washed with aqueous sodium bicarbonate and water, dried over anhydrous magnesium sulfate and then vaporated in vacuo. The residue was chromatographed on silica gel (60 g) i~2: 1 dichloromethaneacetone to give 36 (0.34 1,3,. Deacetylation of 36 (0.29 g) was performed as described for 34, and chromatography on silica gel (30 g) in 9: 1 chloroform-methanol gave 37 (0.22 g, 93.S%) 1,3 ,3,4,.…”

“…Deacetylation of 34 (S.9 g) was performed as described for 31 to give 35 (S.6 g, quantitive yield), RfO.20 in S : 1 toluene-ethyl acetate, [a]o +34.8° (0.31). NMR data (CDCI 3 ): IH,m,aromatic),m,cyclohexyl 1,3,3,4, -glucopyranosylj-sn-glycerol (36). To the mixture of activated molecular sieves 4A (0.6 g) and silver trifluoromethanesulfonate (0.2 g) in dichloroethane (10 ml) was added solutions of 35 (0.24 g) in dichloroethane (S ml) and 2,3,4,6-tetra-0-acetyl-a-D-glucopyranosyl bromide (0.25 g) in dichloroethane (5 ml), successively, at -5 /'-10°C under arg0n.…”

“…A mixture of 33 (S.3 g), 1,I-dimethoxycyclohexane (2.9 g) and ptoluenesulfonic acid (100 mg) in dimethylformamide (SO ml) was stirred for 2 hr at 40°C under reduced pressure (20 mmHg). After neutralization with triethylamine (2 ml), the mixture was evaporated in vacuo, and then the residue was chromatographed on silica gel (SOO g) in 2: 1 toluene-ethyl acetate to give 34 (6.0 g, 98 1,3 ,. Deacetylation of 34 (S.9 g) was performed as described for 31 to give 35 (S.6 g, quantitive yield), RfO.20 in S : 1 toluene-ethyl acetate, [a]o +34.8° (0.31).…”