1: With sodium hydroxide in toluene 1 h; 2: With hydrogenchloride in toluene T=60 - 95°C; pH=2.5; 5 h; Further stages.;

1: sodium hydroxide / toluene / 1.75 h / 35 - 40 °C 2: Na2WO4·2H2O; phenyl-phosphonic acid; dihydrogen peroxide; [Me(n-C8H17)3N]HSO4 / toluene; water; acetic acid n-butyl ester / 12.5 h / 50 °C 3: sulfuryl dichloride / acetonitrile / 1.5 h / 0 - 5 °C 4: 2-methyl-5-ethyl-pyridine / acetonitrile / 1.25 h / 50 °C View Scheme

1: sodium hydroxide / toluene / 1.75 h / 35 - 40 °C 2: Na2WO4·2H2O; phenyl-phosphonic acid; dihydrogen peroxide; [Me(n-C8H17)3N]HSO4 / toluene; water; acetic acid n-butyl ester / 12.5 h / 50 °C View Scheme