Abstract: Compounds of formula (I): ##STR1## wherein: R is halogen;Y is hydrogen, NH.sub.2, SH or OH;X is: ##STR2## wherein: either R.sub.1 or R.sub.2 is a bond, with the other being hydrogen;either R.sub.3 or R.sub.4 is hydrogen, with the other being hydrogen, OH, OAc or NHAc;R.sub.5 is OH or OAc;either R.sub.7 or R.sub.8 is hydrogen, with the other being OH or OAc;R.sub.9 is hydrogen, CH.sub.2 OH or CH.sub.2 OAc;with the proviso that when R.sub.4 is OH, OAc or NHAc then R.sub.8 is hydrogen;and enantiomers of such compounds, are disclosed. Pharmaceutical formulations comprising such compounds, their use in the treatment of various disease states, and methods of treatment employing the compounds are also provided.