1: With boron trifluoride-tetrahydrofuran complex; triethylamine in acetonitrile T=20°C; 25 h; 2: With methanol 5 h; Reflux; 3: With sodium hydroxide in methanol; water T=20°C; pH=7; 16 h;

1: With boron trifluoride-tetrahydrofuran complex; triethylamine in acetonitrile T=20°C; 25 h; 2: With methanol 5 h; Reflux; 3: With sodium hydroxide in methanol; water T=20°C; pH=7; 16 h;