A compound of formula (I) or its enantiomers or diastereoisomers thereof: ##STR00001## wherein: A, X, W, R.sup.1, Y; R.sup.3; and R.sup.4 are as defined herein.The compounds of the invention may be used as inhibitors of the papilloma virus E1-E2-DNA complex. The invention further provides a method of treating or preventing human papilloma virus infection.