An Efficient Synthesis of Allosamidin

Abstract

The solid-phase synthesis of allosamidin was investigated. After two N-benzyloxycarbonyl (Cbz)-protected trichloroacet­imidate donors were synthesized, the solid-phase synthesis was performed using polystyrene as support and an o-nitrobenzyl ether tether as linker. The target allosamidin was efficiently obtained by iterative glycosylation reactions, catalytic hydrogenation, acetylation, deacetylation, and photolysis.

Key words

carbohydrates - solid-phase synthesis - chitinase - inhibitors - glycosylation

• References and Notes

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• 9 Allosamidin 1: IR (KBr): 3500, 3365, 1652, 1550, 1060 cm^–1; ¹H NMR (300 MHz, D₂O): δ = 5.37 (dd, J = 8.7, 4.9 Hz, 1 H, H-1), 4.80 (d, J = 8.5 Hz, 1 H, H-1′′), 4.78 (d, J = 8.3 Hz, 1 H, H-1′), 4.37 (dd, J = 8.7, 4.1 Hz, 1 H, H-2), 4.36 (t, J = 2.9 Hz, 1 H, H-3′), 4.30 (t, J = 5.0 Hz, 1 H, H-3), 4.07 (t, J = 2.8 Hz, 1 H, H-3′′), 3.92–2.66 (m, 12 H), 3.61 (dd, J = 12.0, 6.5 Hz, 1 H, H-6′), 3.09 (s, 3 H, NCH ₃Me), 3.08 (s, 3 H, NCH ₃Me), 3.67–3.63 (m, 1 H, H-5), 2.09 (s, 3 H, NHCOCH ₃), 2.07 (s, 3 H, NHCOCH ₃); ¹³C NMR (75 MHz, D₂O): δ = 174.03, 173.79, 160.61, 100.58, 99.92, 86.79, 85.01, 80.48, 76.90, 73.63, 72.59, 70.11, 68.95, 66.40, 64.18, 60.97, 60.84, 59.20, 53.01, 52.63, 51.42, 37.60, 37.41, 22.05; ESI-MS: m/z = 645.2 [M + Na]⁺