Kaolinitic clay in tetrachloromethane 4 h; Heating;

1: aluminum isopropoxide / toluene; butanone / Reflux 2: hydroxylamine hydrochloride; pyridine / ethanol / 20 °C / Inert atmosphere 3: thionyl chloride / tetrahydrofuran / 0 - 20 °C 4: hydrogenchloride; water / tetrahydrofuran / 1 h / 25 °C View Scheme

CrO3/NHPI on activated clay in dichloromethane T=20°C;