2: acetonitrile; H2O / 1) pH 9.5; 2) pH 6 3: 1) triethylamine, chloroformic acid ethylester / 1) CH2Cl2, -15 deg C; 2 h, 0 deg C; 2) -15 deg C View Scheme

1: acetonitrile; H2O / 1) pH 9.5; 2) pH 6 2: 1) triethylamine, chloroformic acid ethylester / 1) CH2Cl2, -15 deg C; 2 h, 0 deg C; 2) -15 deg C View Scheme

chloroformic acid ethyl ester; triethylamine 1) CH2Cl2, -15 deg C; 2 h, 0 deg C; 2) -15 deg C; Yield given. Multistep reaction;