Synthesis and glycosidase inhibitory activity of some N-substituted 5a-carba-β-fuco- and β-galactopyranosylamines, and selected derivatives

Synthesis of carbasugar-containing non-glycosidically linked pseudodisaccharides and higher pseudooligosaccharides

“…The reactions of a-gluco or a-galacto carbasugar epoxides (16)(17)(18)(19)(20) with amines (21)(22)(23)(24)(25)(26)(27) to give epoxide-opened coupling products (28-38; Table 2) 12-16 are reported to be generally slower than those for the carbamannosides, and the yields tend to be lower. Regioselectivity is an issue in such reactions and regioisomeric mixtures of products were formed in some cases ( Table 2, entries 2 and 6).…”

“…A 3,4-cyclohexylidene 6-deoxygalacto epoxide (20) also gave exclusive C-1 attack ( Table 2, entry 8), leading to the formation of a 1,1-linked di-L-fucoside (38). 16 The a-gluco/galacto type epoxides shown in Table 2 must open to give trans-diequatorial products if a carbadisaccharide is to result from attack at C-1. Fürst-Plattner favoured trans-diaxial opening would arise from a C-2 attack, which would not lead to a carbadisaccharide product.…”

“…39 Conformationally locked 1,6-anhydro galacto 3,4-epoxides: 1,6-Anhydrosugar epoxides (126-133) were opened by carbasugar C-1 amines (27, 28, 95, 120-123) with excellent regioselectivity to give the trans-diaxial products, i.e., the 4-substituted glucoconfigured compounds (135-146), in good yields (55-93%; Table 5, entries 1-11). 16,[40][41][42][43][44][45][46] The reactions seem to be sensitive to steric considerations: A more hindered amine (121) reacted more slowly than a less hindered amine (120) (cf. Bn* = CD 2 Ph.…”

“…epoxides(16)(17)(18) were heated with alcohols and base in DMF. Even a simple model alcohol, octanol, gave the coupling product in only 5% yield 12,13.…”

Antioxidant Activities and α-Glucosidase Inhibitory Effect of Water Extracts from Medicinal Plants

“…추출된 각 시료는 일정 농도로 희석한 후 시 료 100 ㎕ 에 100 mM sodium phosphate (pH 7.4) 250 ㎕, 1 mM EDTA 100 ㎕, 36 mM deoxyribose 100 ㎕, 1 mM Ogawa et al, 2004). 결과 및 고찰 …”