Disclosed is an isomer, enantiomer, diastereoisomer or tautomer of a compound represented by Formula I: ##STR00001## or a salt thereof, in which R.sup.1, R.sup.2, R.sup.100, R.sup.200, A, A.sup.1, B, B.sup.1, BG, n, Q and Q.sup.1 are substituents described. Also disclosed is the use of compounds of Formula 1 to treat proliferative disorders.