1: in acetonitrile T=0 - 5°C; 3 h; 2: With hydrogenchloride; water in toluene; acetonitrile pH=3; 3: With sodium hydrogencarbonate in water; toluene

hydrogenchloride in acetonitrile T=0°C; Desilylation; 0.0833333 h;

1: in acetonitrile T=5°C; 1.16667 h; 2: With hydrogenchloride; water in ethyl acetate pH=3; 3: With sodium hydrogencarbonate in water; ethyl acetate

hydrogenchloride in acetonitrile T=0°C; Desilylation; 0.5 h;

hydrogenchloride in acetonitrile T=0°C; Desilylation; 0.5 h;

1: Et3N / dimethylformamide / 18 h / 20 °C 2: oxalyl chloride; DMF / CH2Cl2 / 2 h / 20 °C 3: Et3N / CH2Cl2 / 0.5 h / -20 °C 4: toluene / 0.5 h / 20 °C 5: 1,3,5-trimethyl-benzene / 3 h / Heating 6: 88 percent / 1N aq. HCl / acetonitrile / 0.08 h / 0 °C View Scheme

1.1: CDI / acetonitrile / 1 h / 20 °C 1.2: 86 percent / acetonitrile / 15 h / 20 °C 2.1: 90 percent / boron trifluoride diethyl etherate / acetonitrile / 3 h / 20 °C 3.1: 89 percent / Et3N / dimethylformamide / 2 h / 0 °C 4.1: Et3N / CH2Cl2 / 0.25 h / 0 °C 5.1: Et3N / CH2Cl2 / 0.5 h / -20 °C 6.1: toluene / 0.5 h / 20 °C 7.1: 1,3,5-trimethyl-benzene / 3 h / Heating 8.1: 88 percent / 1N aq. HCl / acetonitrile / 0.08 h / 0 °C View Scheme

1: 89 percent / Et3N / dimethylformamide / 2 h / 0 °C 2: Et3N / CH2Cl2 / 0.25 h / 0 °C 3: Et3N / CH2Cl2 / 0.5 h / -20 °C 4: toluene / 0.5 h / 20 °C 5: 1,3,5-trimethyl-benzene / 3 h / Heating 6: 88 percent / 1N aq. HCl / acetonitrile / 0.08 h / 0 °C View Scheme

1: toluene / 0.5 h / 20 °C 2: 1,3,5-trimethyl-benzene / 3 h / Heating 3: 88 percent / 1N aq. HCl / acetonitrile / 0.08 h / 0 °C View Scheme

1: 1,3,5-trimethyl-benzene / 3 h / Heating 2: 88 percent / 1N aq. HCl / acetonitrile / 0.08 h / 0 °C View Scheme