Synthetic Studies on Rhynchosporoside and Related Substances

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

“…Chromatographic comparison of 1 and 60 with the natural product (rhynchosporoside) showed the same Rfvalue (0.30) on high performance thin layer chromatography. Even though comparison of the 1H -NMR data for the samples of synthetic materials (1,2,3,4,59,60,65,68,71,74) with those reported for rhynchosporoside 4 ) did not allow identification of the structure of the natural product,7) both the results of biological tests and chromatographic comparison strongly suggested that rhynchosporoside comprises the a-Dcellobioside and ex-D-cellotrioside of 3-deoxy-2(R)-glycerol (1, 60). Strobel and Sugawara also comfirmed the biological results, using tetra-and pentaglucosides of 3-deoxy-2(R)-and 2(S)-glycerols, reported by Nicolaou et al 13 ) (R)-Isomers were more active than (S)-isomers, however, the minimum concentrations of samples were the same as those of the di-and triglucosides (unpublished results).…”

“…After deacetylation, the aanomers (37, 41) were separated from the 13-anomers (39, 43) by chromatography. Glycosylation of a-D-glucopyranosides (31, 30, 37, 41) with 4-0- (2,3,4,6- glucopynanosyl)-2,3,6-tri-O-acetyl-a-D-glucopyranosyl bromide (11) was successfully performed with silver triflate and activated molecular sieves to give cellotriosides (1,2,3,4) after deprotection. Both "the l3C_ and lH-NMR spectra supported these structures.…”

“…6 ) We describe here the stereoselective synthesis of land 2-0-cellotriosyl-3-deoxy-2(R)-and 2(8)-glycerols (1,2,3,4) and the alternative synthesis of 1-0-a-D-cellobiosyl-glycerols (59, 60) in detail. 68,74) were also synthesized for comparison with the published data for the natural products.…”

“…A solution of 44 (600 mg) in methanol (10 ml) containing 5 N sodium methaoxide (0. (1). A mixture of 45 (3IOmg) and 10% palladium on active carbon (350 mg) in methanol (10 m!)…”

Inhibitors of endo-α-mannosidase. Part III. Congeners of 1-deoxy-3-O-(α-D-glucopyranosyl)-mannojirimycin modified in the glucose unit

“…The 1-deoxymannojirimycin derivative 2 (6, 7), which has a free hydroxyl group at the 3-position, was used as the glycosyl acceptor. The chloro sugars 3 (2-0-methyl), 5 (3-deoxy) (R), 6 (4-deoxy), 10 (4-0-methyl), 11 (galactosyl) (9), 12 (6-deoxy), 13 (xylosyl) (lo), 50 (3-0-methyl), and 51 (6-0-acetyl) (11) were prepared from the corresponding hemiacetals by treatment with oxalyl chloride and N,N-dimethylformamide (12,13 (14)(15)(16)(17)(18)(19), except for 4-0-methyl 9, which was synthesized from an anomeric mixture of 7 (20) by conventional methylation with methyl iodide and sodium hydride to give 8, followed by deallylation (9).…”