1.1: 1-methyl-pyrrolidin-2-one / 50 - 100 °C 2.1: triethylamine / N,N-dimethyl-formamide / 0.25 h / -5 °C 2.2: 3 h / -5 °C 3.1: N,N-dimethyl-formamide / 1.83 h / -5 °C View Scheme

in 1-methyl-pyrrolidin-2-one T=50 - 100°C;