wherein Z1 is a suitable leaving group, such as halogen or Y1SO2O???; (b) for compounds of formula I in which q is 0 and R6 and R7 both represent H, reduction of a compound of formula IV, using a suitable reducing agent; (c) for compounds of formula I in which q is 0 and R9 and R10 both represent H, reduction of a compound of formula V, using a suitable reducing agent; (d) for compounds of formula