phosphoric acid; dimethyl sulfoxide; dicyclohexyl-carbodiimide 1.5 h; Ambient temperature;

1: 1) p-nitrobenzoyl chloride, 2) AgNO3 / 1) CHCl3, -7 to -5 deg C, 2) -10 to 55 deg C 2: 30 percent / PCl3 / CHCl3 / Ambient temperature 3: 60 percent 4: 71 percent / DMSO, N,N'-dicyclohexylcarbodiimide, H3PO4 / 1.5 h / Ambient temperature View Scheme

1: 30 percent / PCl3 / CHCl3 / Ambient temperature 2: 60 percent 3: 71 percent / DMSO, N,N'-dicyclohexylcarbodiimide, H3PO4 / 1.5 h / Ambient temperature View Scheme

pyridine; p-toluenesulfonyl chloride 1. dimethylformamide, -5 deg C 2. DMF, 2h; Yield given. Multistep reaction;