1: LiBr, H2O / dimethylformamide / 6 h / Heating 2: 1 h / subtilisin, pH 7 buffer 3: 20 h / kidney acylase I, pH 7 buffer 4: Na2CO3 / tetrahydrofuran; H2O 5: 60 percent / NBS, H2O / dimethylformamide 6: 80 percent / tetrahydrofuran View Scheme

1: LiBr, H2O / dimethylformamide / 6 h / Heating 2: 1 h / subtilisin, pH 7 buffer 3: 20 h / kidney acylase I, pH 7 buffer 4: Na2CO3 / tetrahydrofuran; H2O View Scheme

1: LiBr, H2O / dimethylformamide / 6 h / Heating 2: 1 h / subtilisin, pH 7 buffer 3: 20 h / kidney acylase I, pH 7 buffer View Scheme

1: LiBr, H2O / dimethylformamide / 6 h / Heating 2: 1 h / subtilisin, pH 7 buffer 3: 20 h / kidney acylase I, pH 7 buffer 4: Na2CO3 / tetrahydrofuran; H2O 5: 78 percent / SO2Cl2 6: 92 percent / Bu3SnH, AIBN / toluene View Scheme