Reaction Steps
S-trans, trans-Farnesyl-L-cysteine (500 mg, 1.54 mmol) was dissolved in mixture of THF and a first portion of K2CO3 (3 mmol) and the resulting solution was cooled to 5° C. with vigorous stirring. To this stirred solution was added 3-methylenedihydro-2,5-furandione (302 mg, 3.07 mmol) portionwise while maintaining the pH at 9.0-10.0 with another portion of K2CO3 (3 mmol). The mixture was stirred at room temperature for 3 h. HPLC analysis showed completion of the reaction. The pH of the reaction mixture then adjusted to 2.0 by the addition of 2 N HCl solution. The acidic solution was extracted three times with 15 mL of ethyl acetate. The combined organic extract was washed with water, brine and dried over Na2SO4, the solvent was removed under reduced pressure to afford crude Compound F, which was further purified by preparative HPLC (552 mg, 82%) to yield Compound F. 1H-NMR (500 MHz, CDCl3): δ 1.59 (s, 6H), 1.67 (s, 3H), 1.68 (s, 3H), 2.05 (m, 8H), 2.88 (dd, J=6.5, 14.0, 1H), 2.95 (dd, J=6.5, 14.0, 1H), 3.17-3.15 (m, 2H), 3.36 (d, J=14 Hz, 1H), 4.77 (dd, J=6, 12.5 Hz, 1H), 5.09 (bt, 2H), 5.22 (t, J=7.5 Hz, 1H), 5.93 (s, 1H), 6.46 (s, 1H). 13C-NMR (125 MHz, CDCl3): δ 16.0, 16.2, 17.7, 25.7, 26.7, 29.9, 32.8, 39.6, 39.7, 40.2, 52.0, 119.4, 123.7, 131.3, 132.0, 135.4, 140.3, 170.3, 171.5, 176.0; ES-MS: mass calcd for Chemical Formula: C23H35NO5S 437.6. Found (M+Na) m/z 446.
