Reaction Steps
In a 100 mL round bottom flask, to a solution of methyl 2-(chlorosulfonyl)benzoate (281 mg, 1.2 mmol) and S-trans, trans-farnesyl-L-cysteine (325 mg, 1 mmol) in THF (5 mL) was added N,N-diisopropyl-ethyl-amine (0.52 mL, 3 mmol) dropwise. The solution was stirred at room temperature for 4 h. The mixture was diluted with ethyl acetate (60 mL) and washed sequentially with an NH4Cl saturated solution (10 mL×2), H2O (10 mL×1) and brine (10 mL×1). The organic layer was dried over Na2SO4 and concentrated in vacuo. The resulting residue was dissolved in THF (3 mL) and a solution of LiOH.H2O (210 mg, 5 mmol) in H2O (2 mL) was added slowly at 0° C. The reaction was left at room temperature overnight. The reaction was quenched with 1 N HCl and pH was adjusted to 2.0. The solution was then extracted by ethyl acetate (30 mL×3). The organic layer was dried over Na2SO4 and concentrated in vacuo. The residue was then further purified by preparative HPLC (290 mg, 57%) to yield Compound N-81. 1H-NMR (500 MHz, CD3OD): δ 1.50 (s, 6H), 1.55 (s, 3H), 1.57 (s, 3H), 1.86-1.89 (m, 2H), 1.94-2.02 (m, 6H), 2.71 (dd, J=6.0, 14.0 Hz, 1H), 2.77 (dd, J=5.5, 14.0 Hz, 1H), 3.01-3.08 (m, 2H), 4.10 (t, J=6.0 Hz, 1H), 5.00-5.06 (m, 3H), 7.56-7.62 (m, 2H), 7.84 (d, J=6.5 Hz, 1H), 7.93 (d, J=7.5 Hz, 1H). 13C-NMR (125 MHz, CD3OD): δ 16.17, 16.28, 17.81, 24.24, 25.96, 27.36, 27.78, 30.52, 34.79, 40.75, 40.89, 57.80, 121.53, 125.14, 125.46, 130.07, 132.13, 132.56, 133.78, 136.28, 140.63, 140.72, 170.16, 173.07; ES-MS: mass calcd for Chemical Formula: C25H35NO6S2 509.68. Found (M+Na) m/z 532.1.
