potassium carbonate in dimethyl sulfoxide T=100°C; 5.5 h;

1: 4-hydroxy-benzaldehyde With potassium carbonate in DMF (N,N-dimethyl-formamide) 0.166667 h; 2: 2-bromo-1-ethanol in DMF (N,N-dimethyl-formamide) 3 h; Heating / reflux;

diethylamino-sulfur trifluoride in ethylene glycol dimethyl ether T=20°C; Cooling with ice;

1.1: triethylamine / dichloromethane / 12 h / 20 °C 2.1: sodium tetrahydroborate / methanol / 1.25 h / 0 - 20 °C 3.1: phosphorus tribromide / dichloromethane / 20 °C 4.1: sodium hydride / N,N-dimethyl-formamide / 0.5 h / -10 - -5 °C 4.2: 3 h / -5 - 0 °C 5.1: toluene / 12 h / 70 - 75 °C 6.1: hydrogen / palladium-on-charcoal / ethyl acetate / 30 - 35 °C / 2942.29 - 3677.86 Torr View Scheme

1.1: triethylamine / dichloromethane / 12 h / 20 °C 2.1: sodium tetrahydroborate / methanol / 1.25 h / 0 - 20 °C 3.1: phosphorus tribromide / dichloromethane / 20 °C 4.1: sodium hydride / N,N-dimethyl-formamide / 0.5 h / -10 - -5 °C 4.2: 3 h / -5 - 0 °C 5.1: toluene / 12 h / 70 - 75 °C View Scheme

triethylamine in dichloromethane T=0 - 20°C; Inert atmosphere;

1: 1.) copper acetate monohydrate, 2.) 2 N HCl / 1.) water, ethanol, reflux, 30 min, 2.) reflux, 2 h 2: 74 percent / pyridine / 6 h View Scheme

piperidine; ethanol