1.1: acetic acid / N,N-dimethyl-formamide / 0.5 h / 45 °C 1.2: 4 h 2.1: potassium carbonate / 0 - 20 °C 3.1: triethylamine / dichloromethane / 0 °C 4.1: potassium formiate; formic acid / acetic anhydride / 100 °C View Scheme

1.1: acetic acid / N,N-dimethyl-formamide / 0.5 h / 45 °C 1.2: 4 h 2.1: potassium carbonate / 0 - 20 °C 3.1: triethylamine / dichloromethane / 0 °C 4.1: potassium formiate; formic acid / acetic anhydride / 100 °C 5.1: .alpha.,.alpha.,.alpha.-trichloroacetamide; dihydrogen peroxide; dipotassium hydrogenphosphate / dichloromethane / 10 - 20 °C View Scheme

1.1: acetic acid / N,N-dimethyl-formamide / 0.5 h / 45 °C 1.2: 4 h 2.1: potassium carbonate / 0 - 20 °C View Scheme