nsaturated ring in combination therewith, wherein the ring may be substituted or not substituted, R14 represents the alkyl group with or without substituent, aryl group with or without substituent, alkoxy group with or without substituent, or a group of ##STR308## wherein R12 and R13 are the same as defined above, R15 is a hydrogen atom, or alkyl group, aryl group or alkoxy group each of which may