Scheme 2. Synthetic route of combretastatin A-4 sulfamate derivatives. Reagents and conditions: a) Ph3CCl(TrCl), THF, Et3N, rt, 2 h; b) n-BuLi, THF, −78 °C, 30 min, then adding 14/THF solution, −78 °C–RT, overnight; c) 37% HCl (aq.), toluene, rt, 2 h; d) NaH, DMF, RSO2Cl (R = NH2, NHMe, N(Me)2), 0 °C to RT, overnight; e) H2 (1 atm), 10% Pd/C, EtOH, rt, 3 h.
