1: 92 percent / Zn, conc. HCl / ethanol / 0.83 h / 65 - 70 °C 2: Br2, K2CO3 / CH2Cl2; diethyl ether / 0.33 h / Ambient temperature 3: CH2Cl2; diethyl ether / 0.5 h / Ambient temperature 4: 1.) KOH, 2.) AcOH, O2 / 1.) aq. EtOH, reflux, 3 h, 2.) aq. EtOH, reflux, 1.5 h View Scheme

sodium tetrahydroborate; boron trifluoride diethyl etherate in tetrahydrofuran Reduction;

1: Raney nickel; ethanol / 160 °C / 110326 Torr / Hydrogenation 2: SO2Cl2; diethyl ether / Erhitzen des Reaktionsprodukts mit wss. Natriumacetat 3: aq. NaOH solution / 180 °C View Scheme

1: 3-oxopentanoic acid ethyl ester With sodium nitrite in acetic acid Substitution; 2: acetylacetone With sodium acetate; zinc Cyclization;

carbon disulfide; aluminium trichloride