NTION by the general formulai wherein: R is hydrogen, lower alkyl such as methyl or ethyl or halogen; R is hydrogen, lower alkyl such as methyl or ethyl, cyano or halogen; R is lower alkyl, or lower cycloalkyl; R and R are each hydrogen, lower alkyl, or lower cycloalkyl; R and/or R, and/or may be c hen ically joined to form a ring structure; and, x is a positive integer greater than l.