Also preferred for the group D of formulae (1), (8) and (9) are groups of the formula (i), (ii), (iii), (vii) and (viii) described as follows: ##STR7## wherein X is an oxygen or sulfur atom, R'1 to R'4 each are independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group or a halogen atom; ##STR8## wherein X is an oxygen or sulfur atom, R'5