1.1: subtilisin E; N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid / acetonitrile / 6 h / 25 °C 2.1: n-BuLi / tetrahydrofuran 2.2: 63 percent / tetrahydrofuran 3.1: subtilisin Carlsberg; N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid / acetonitrile / 24 h / 25 °C View Scheme

recombinant subtilisin E in water T=37°C; pH=8.0; 3 h;

1: (S)-(+)-p-toluenesulfinamide With n-butyllithium in tetrahydrofuran 2: chloroacetic acid anhydride in tetrahydrofuran

N,N-bis-2-(hydroxyethyl)-2-amino ethane sulfonic acid; subtilisin E in acetonitrile T=25°C; 6 h;