Journal of the American Chemical Society, , vol. 70, p. 2115,2116 Org.Synth.Coll.Vol., , vol. IV, p. 588 Chemicke Listy, , vol. 37, p. 208,211 Chem.Abstr., , p. 2113 Zeitschrift fuer Naturforschung, , vol. 2b, p. 186