1: 1.) cetyltrimethylammonium bromide, aq. Na2S2O4, 2.) aq. KOH / 1.) THF, 2.) THF, RT, 14 h 2: 88 percent / 2N aq. KOH / 24 h / Ambient temperature 3: 1.) POCl3, 2.) 1N aq. HCl / 1.) reflux, 1 h, 2.) reflux, 1 h 4: 76 percent / K2CO3 / acetone View Scheme