1: 1) 1H-tetrazole, 2) 85percent m-chloroperoxybenzoic acid / 1) THF, 20 deg C, 20 min, 2) 20 deg C, 10 min 2: 75 percent / sodium dithionite, sodium carbonate / acetonitrile; H2O / 1 h / 50 °C View Scheme