Acetic Acid → (2S,4aR,6aR,7R,9S,10aS,10bR)-9-(Azido)-2-(3-furanyl)-dodecahydro-6a,10b-dimethyl-4,10-dioxo-2H-naphtho[2,1-c]pyran-7-carboxylic acid methyl ester

Participants

Reaction Steps

A solution of 36 (0.10 g, 0.22 mmol), sodium azide (0.05 g, 0.77 mmol) and glacial acetic acid in DMF (3 mL) was stirred at room temperature for 4 h. H2O (30 mL) was added and the mixture was extracted with EtOAc (20 mL). The EtOAc solution was washed with H2O (2×20 mL) and saturated NaCl (20 mL) and dried (Na2SO4). Removal of the solvent under reduced pressure afforded a crude solid. The crude solid was purified by column chromatography (eluent: 30% EtOAc/n-hexanes) to afford 0.08 g (86%) of 38 as a white solid, mp 200-203° C. (EtOAc/n-hexanes); 1H NMR (CDCl3): δ 1.13 (3H, s); 1.48 (3H, s); 1.68 (5H, m); 2.14 (31H, m); 2.34 (1H, ddd, J=3.6, 7.2, 27); 2.60 (1H, dd, J=5.1, 13.2); 2.72 (1H, dd, J=3.3, 13.2); 3.74 (3H, s); 3.92 (1H, dd, J=7.5, 12.6), 5.56 (1H, dd, J=5.1, 11.7); 6.39 (1H, dd, J=0.9, 1.8); 7.41 (1H, dd, J=1.2, 2.1); 7.43 (1H, dd, J=0.9, 1.5).

Provenance & Evidence