1.1: N-ethyl-N,N-diisopropylamine / dichloromethane / 0 - 5 °C 1.2: pH 3.5 1.3: 20 °C 2.1: ammonium molibdate; tetrabutylammomium bromide; dihydrogen peroxide / dichloromethane / 10 h / 0 - 5 °C 3.1: sodium methylate / tetrahydrofuran / -15 - 10 °C View Scheme