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Reagents and conditions: (a)95 KOH, H2O, 70 °C, 0.5 h, then acidified to pH 8–9 with 1 M HCl, then Aliquat 336, KI, RBr, reflux, 12 h, 69–75%; (b) NaNO2, HNO3, DCM, 0 °C, 1 h, 80–90%; (c)93,95,96 P(OEt)3, reflux, 4 h, 55–62%; (d)94,96 sulfur powder, NMP, 70 °C, 0.5 h, then 180 °C, 17 h, 50–60%; (e)95,96 selenium powder, NMP, 70 °C, 0.5 h, then 180 °C, 17 h, 52–58%; (f) NaH, RBr, THF, reflux, 17 h, 70–80%.
