in acetonitrile T=15°C; 1 h; UV-irradiation;

1.1: 20 percent Spectr. / acetonitrile / 24 h / 15 °C / Irradiation 2.1: 89 percent / 4-N,N-dimethylaminopyridine; N,N'-dicyclohexylcarbodiimide / CHCl3 / 24 h / 60 °C 3.1: acetonitrile / 1 h / 15 °C / Irradiation 3.2: ethanol; benzene / 1 h 4.1: acetonitrile / 4 h / 15 °C / Irradiation 4.2: 85 percent / ethanol; benzene / 1 h View Scheme