... x X' Y Y' P. Herdewijn, R. Pauwels, M. Baba, J. Balzarini, and E. De Clercq* Rega Institute for Medical Research, Katholieke Uniuersiteit Leuven, B-3000 Leuuen, Belgium. Received May 1 I, 1987 ... Page 2. 2132 Journal of Medicinal Chemistry, 1987, Vol. 30, No. 11 ...