Compounds of the formula (I), wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and p are as defined within and a pharmaceutically acceptable salts and in vivo hydrolysable esters are described. Also described are processes for their preparation and their use as medicaments, particularly medicaments for producing a cell cycle inhibitory (anti-cell-proliferation) effect in a warm-blooded animal, such as man. ##STR00001##