1: 2N HCl / acetic acid 2: 1.) 4-hydroxy-3-nitrobenzophenone fixed to a polystyrene matrix, 2.) triethylamine / 2.) DMF, 30 min 3: 85 percent / 2N HCl / acetic acid / 0.5 h View Scheme

1: 2N HCl / acetic acid 2: 1.) 4-hydroxy-3-nitrobenzophenone fixed to a polystyrene matrix, 2.) triethylamine / 2.) DMF, 30 min View Scheme

di-tert-butyl sulfide in water; trifluoroacetic acid 0.75 h; Ambient temperature;