1: 1.) N-methylmorpholine, isobutyl chloroformate, 2.) N-hydroxy-2-thiopyridone, Et3N, 3.) t-butyl thiol 2: 87 percent / aq. LiOH / tetrahydrofuran / 1.5 h 3: 74 percent / 6M HCl / 3 h / Heating View Scheme