1: 95 percent / 20percent HCl / 2 h / 85 - 90 °C 2: 1.) isobutyl chloroformate, 1,8-diazabicyclo<5,4,0>undec-7-ene (DBU) / 1.) CHCl3, r.t., 1 h, 2.) CHCl3, r.t., 3 h View Scheme

1: 95 percent / 20percent HCl / 2 h / 85 - 90 °C 2: 1.) isobutyl chloroformate, 1,8-diazabicyclo<5,4,0>undec-7-ene (DBU) / 1.) CHCl3, r.t., 1 h, 2.) CHCl3, r.t., 3 h View Scheme

hydrogenchloride T=85 - 90°C; 2 h;