Reaction Steps
To a suspension of ginkgolide B (0.030 g, 0.071 mmol) and K2CO3 (0.030 g, 0.212 mmol) in acetonitrile (0.5 mL) was added iodomethane (0.020 g, 0.141 mmol) The reaction mixture was heated under reflux for 30 min. This reaction resulted in a mixture of 10-methoxy-ginkgolide B and 1-methoxy ginkgolide B in a ratio of 4 to 1. 10-Methoxy-ginkgolide B was separated using an HPLC semi-preparative C18 column (7.8 mm×30 cmL) with a mobile phase of MeOH/H20 (40:60) at a flow of 2 mL/min to give the final product as a white solid (0.017 g, 56%). 1H NMR (400 MHz, CD3OD): δ 1.14 (s, tert-butyl), 1.24 (d, J=7.1, CH3), 1.90 (dd, J=14.2, 4.6, 8-H), 2.06 (td, J=13.9, 4.3, 7α-H), 2.25 (dd, J=13.6, 4.6, 7β-H), 3.05 (q, J=7.1, 14-H), 3.80 (s, OCH3), 4.24 (d, J=7.4, 1-H), 4.57 (d, J=7.4, 2-H), 4.93 (s, 10-H), 5.43 (d, J=4.1, 6-H), 6.10 (s, 12-H). 13C NMR (75 MHz, CD3OD): δ 7.6, 7.0, 29.6 (3 C), 32.9, 37.6, 41.8, 48.8, 68.6, 70.5, 71.5, 74.4, 80.4, 82.2, 84.8, 90.9, 98.2, 110.3, 171.1, 173.0, 175.4. [Hu, L., Chen, Z., Xie, Y., Jiang, Y., & Zhen, H. (2000) Bioorg. Med. Chem. 8, 1515–1521]
