well as those groups specifically illustrated by the examples herein below among the preferred halo c 1 7 alkyl groups are difluoro or trifluoro methyl or ethyl the term u201c hydroxy c 1 7 alkyl u201d u201c c 1 7 hydroxyalkyl u201d or u201c c 1 7 alkyl optionally substituted with hydroxy u201d denotes a c 1 7 alkyl group as defined above wherein at least one of the hydrogen atoms of the alkyl group is replaced by a hydroxy group examples of hydroxy c 1 7 alkyl include but are not limited to methyl ethyl propyl isopropyl isobutyl sec butyl tert butyl pentyl or n hexyl substituted by one or more hydroxy group s in particular with one two or three hydroxy groups preferably with one hydroxy group as well as those groups specifically illustrated by the examples herein below the term u201c cyano c 1 7 alkyl u201d u201c c 1 7 cyanoalkyl u201d or u201c c 1 7 alkyl optionally substituted with cyano u201d denotes a c 1 7 alkyl group as defined above wherein at least one of the hydrogen atoms of the alkyl group is replaced by a cyano group examples of hydroxy c 1 7.