Benzyl 2,3-O-[(1S,2S)-1,2-Dimethoxy-1,2-dimethyl-1,2-ethanediyl]-4-nitrobenzoyl-α-L-xylopyranoside synthesis

Yield:1084896-42-3 86%

Reaction Conditions:

with di-isopropyl azodicarboxylate;triphenylphosphine in tetrahydrofuran at 40 - 62; for 17 h;

Steps:

1

(2S,3S,4aS,5R,8R,8aR)-5-(benzyloxy)-2,3-dimethoxy-2,3-dimethylhexahydro-2H-pyrano[4,3-b][l,4]dioxin-8-ol (2, 8 g, 0.023 mol), triphenylphosphine (11.84 g, 0.045 mol), and 4-nitrobenzoic acid (7.54 g, 0.045 mol) were mixed in THF (80 mL) under nitrogen and heated to 40 ⁰C. Diisopropylazodicarboxylate (9.13 g, 0.045 mol) was added dropwise, then the mixture was heated to 62 ⁰C for 17 h. The reaction was cooled to room temperature, solvent was evaporated, and the product (8) was crystallized from methanol (86%). m.p. 170 - 171 ⁰C. ¹H NMR (300 MHz, CDCl₃): δ 8.21 (d, J = 9 Hz, 2H), 8.10 (d, J = 9 Hz, 2H), 7.37 - 7.19 (m, 5H), 5.14 (m, IH), 4.85 (d, J = 3.6 Hz, IH), 4.71 (d, J = 12.6 Hz, IH), 4.61 (d, J = 12.6 Hz, IH), 4.31 (t, J = 9.9 Hz, IH), 3.89 - 3.77 (m, 2H), 3.58 (t, J = 10.6 Hz, IH), 3.39 (s, 3H), 3.21 (s, 3H), 1.28 (s, 3H), 1.19 (s, 3H).

References:

WO2008/144773,2008,A1 Location in patent:Page/Page column 30