1. S. S. Novikov, L. I. Khmel'nitskii, O. V. Lebedev, L. V. Epishina, L. I. Suvorova, L. V. Lapshina, V. D. Krylov, I. V. Zaikonnikova, I. E. Chasovskaya-Zimakova, V. S. Chudnovskii, and V. A. Babichev, Inventor's Certificate No. 366709, 10/28/1972; Byull. Izobr., No. 15 (1978).
2. H. Petersen, Synthesis,5, 243 (1973).
3. J. Tafel and P. A. Houseman, Ber.,40, 3743 (1907).
4. H. Blitz, Ber.,41, 1880 (1908).
5. K. Keiko and U. Jo, Chem. Pharm. Bull., (Tokyo)19, 110 (1971).