. "If the Ar group of the Hydroxyiminopiperazine Compound wherein R4 is ???H is substituted with a hydroxyl or amino group or ???R3 is a hydroxyl or amino group, the hydroxyl or amino group is protected using a suitable protecting group, using methods well known to those skilled in the art, before being reacted with the isocyanate of formula R9???N???C???O, Suitable protecting groups include, but are" . . . . . .