aSynthetic Scheme towards screening hit and analogs.
aReagents and conditions. a) EtOH, CHCCH2Br, reflux, 47% yield; b) Pd(PPh3)4, CuI, DMF, rt, 72% yield; c) TMSI, toluene; d) py, Et3N, PPh2I; e) 30% H2O2, 30–50% yield over 2 steps; f) sulfur, 30–50% yield over 2 steps; g) Me2SO4, 1,4-dioxane, sealed tube, 100–120 °C, 30–50% yield.