Chemical modification of trehalose. Part XIV. Some tetra- and hexadeoxy-derivatives and their amino-analogues

Abstract

2,2′,3,3′-Tetradeoxy-αα-trehalose has been synthesised by palladium-catalysed hydrogenolysis of the 2,2′-diene, 4,6-O-benzylidene-2,3-dideoxy-α-D-erythro-hex-2-enopyranosyl 4,6-O-benzylidene-2,3-dideoxy-α-D-erthro-hex-2-enopyranoside, which reduced the double bonds and removed the benzylidene substituents simultaneously. The derived tetramesylate underwent replacement of all four sulphonate groups when treated with either azide or benzoate ions to give the threo-analogues. Selective displacement of the primary sulphonyloxy-groups was achieved with iodide ion and the 6,6′-di-iodo-derivative was subjected to reductive dehalogenation. The resulting 2,2′,3,3′,6,6′-hexadeoxy-4,4′-dimesylate underwent a ready displacement with azide anion to give the 4,4′-diazide, but when benzoate ion was employed as nucleophile products arising from both nucleophilic displacement and elimination were obtained.