trifluoroacetic acid in various solvent(s) 1.) -30 deg C, 2.) -20 deg C, 20 min, 3.) -10 deg C, 20 min;

1: 1.) N-trichloroethoxycarbonylation, 2.) benzhydryl esterification 2: 1.) Na2CO3, 2.) H2O / 1.) dioxane, 5 deg C, then 20 deg C, 12 h, 2.) 1 h 3: 1.) PhN=C=NPh, 2.) N,N-dimethylaniline / 1.) CH2Cl2, 18 h, 0 deg C, 2.) CH2Cl2 4: 56 percent / CF3COOH / various solvent(s) / 1.) -30 deg C, 2.) -20 deg C, 20 min, 3.) -10 deg C, 20 min View Scheme

1: 1.) Na2CO3, 2.) H2O / 1.) dioxane, 5 deg C, then 20 deg C, 12 h, 2.) 1 h 2: 1.) PhN=C=NPh, 2.) N,N-dimethylaniline / 1.) CH2Cl2, 18 h, 0 deg C, 2.) CH2Cl2 3: 56 percent / CF3COOH / various solvent(s) / 1.) -30 deg C, 2.) -20 deg C, 20 min, 3.) -10 deg C, 20 min View Scheme

1: 1.) PhN=C=NPh, 2.) N,N-dimethylaniline / 1.) CH2Cl2, 18 h, 0 deg C, 2.) CH2Cl2 2: 56 percent / CF3COOH / various solvent(s) / 1.) -30 deg C, 2.) -20 deg C, 20 min, 3.) -10 deg C, 20 min View Scheme

1: 87 percent / H2O, conc. HCl / acetone / 72 h / Ambient temperature 2: 1.) PhN=C=NPh, 2.) N,N-dimethylaniline / 1.) CH2Cl2, 18 h, 0 deg C, 2.) CH2Cl2 3: 56 percent / CF3COOH / various solvent(s) / 1.) -30 deg C, 2.) -20 deg C, 20 min, 3.) -10 deg C, 20 min View Scheme

1: 61 percent / N,N-dimethylaniline / CH2Cl2 / 15 h / 0 °C 2: 56 percent / CF3COOH / various solvent(s) / 1.) -30 deg C, 2.) -20 deg C, 20 min, 3.) -10 deg C, 20 min View Scheme

1: 61 percent / N,N-dimethylaniline / CH2Cl2 / 15 h / 0 °C 2: 56 percent / CF3COOH / various solvent(s) / 1.) -30 deg C, 2.) -20 deg C, 20 min, 3.) -10 deg C, 20 min View Scheme