Ring-opening reactions of sucrose epoxides: Synthesis of 4′-derivatives of sucrose
作者:Riaz Khan、Michael R. Jenner、Harold Lindseth、Khizar S. Mufti、Gita Patel
DOI:10.1016/0008-6215(87)80215-x
日期:1987.5
The 2,1''-O-isopropylidene derivative (1) of 3-O-acetyl-4,6-O-isopropylidene-.alpha.-D-glucopyranosyl 6-O-acetyl-3,4-anhydro-.beta.-D-lyxo-hexulofuranoside and 2,3,4-tri-O-acetyl-6-O-trityl-.alpha.-D-glucopyranosyl 3,4-anhydro-1,6-di-O-trityl-.beta.-D-lyxo-hexulofuranoside have been synthesised and 1 has been converted into 2,3,4,6-tetra-O-acetyl-.alpha.-D-glucopyranosyl 1,6-di-O-acetyl-3,4-anhydro-.beta.-D-lyxo-hexulofuranoside (2). The SN2 reactions of 2 with azide and chloride nucleophiles gave the corresponding 2,3,4,6-tetra-O-acetyl-.alpha.-D-glucopyranosyl 1,3,6-tri-O-acetyl-4-azido-4-deoxy-.beta.-D-fructofuranoside (6) and 2,3,4,6-tetra-O-acetyl-.alpha.-D-glucopyranosyl 1,3,6-tri-O-acetyl-4-chloro-4-deoxy-.beta.-D-fructofuranoside (8), respectively. The azide 6 was catalytically hydrogenated and the resulting amine was isolated as 2,3,4,6-tetra-O-acetyl-.alpha.-D-glucopyranosyl 4-acetamido-1,3,6-tri-O-acetyl-4-deoxy-.beta.-D-fructofuranoside. Treatment of 5 with hydrogen bromide in glacial acetic acid followed by conventional acetylation gave 2,3,4,6-tetra-O-acetyl-.alpha.-D-glucopyranosyl 1,3,6-tri-O-acetyl-4-bromo-4-deoxy-.beta.-D-fructofuranoside. Similar SN2 reactions with 2,3,4,6-tetra-O-acetyl-.alpha.-D-glucopyranosyl 1,6-di-O-acetyl-3,4-anhydro-.beta.-D-ribo-hexulofuranoside (12) resulted in a number of 4''-derivatives of .alpha.-D-glucopyranosyl .beta.-D-sorbofuranoside. The regiospecific nucleophilic substitution at position 4'' in 2 and 12 has been explained on the basis of steric and polar factors.