1: With 1-chloroethyl chlorocarbonate; sodium carbonate in 1,2-dichloro-ethane 3 h; Heating; 2: With methanol T=20°C; Further stages.;

1.1: 1-chloroethyl chlorocarbonate / 1,2-dichloro-ethane / 6 h / Reflux 1.2: 4 h / Reflux 2.1: triethylamine / acetonitrile / 12 h / 20 °C View Scheme

1: 2 h / 120 °C 2: acetic acid; zinc / 16 h / 20 °C 3: triethylamine / acetonitrile / 5 h / 80 °C / |Inert atmosphere 4: dichloromethane / 20 h / 45 °C / |Inert atmosphere; |Cooling with ice 5: 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane; potassium fluoride / acetonitrile / 0.17 h / 80 °C / |Sealed tube View Scheme