u2014 c o or nh c 1 c 6 alkyl c o ar represents a moiety selected from the group consisting of c 1 c 6 alkyl c 1 c 6 fluorinated alkyl c 3 c 6 cycloalkyl tetrahydropyranyl camphoryl adamantyl cn u2014 n c 1 c 6 alkyl 2 phenyl pyridinyl pyrimidinyl furyl thienyl napthyl morpholinyl triazolyl pyrazolyl piperidinyl pyrrolidinyl imidazolyl piperizinyl thiazolidinyl thiomorpholinyl tetrazole indole benzoxazole benzofuran imidazolidine 2 thione 7 7 dimethyl bicyclo 2 2 1 heptan 2 one and pyrrolyl groups each optionally substituted by from 1 to 3 substituents independently selected from the group consisting of halogen u2014 cn u2014 cho u2014 cf 3 ocf 3 u2014 oh u2014 c 1 c 6 alkyl c 1 c 6 alkoxy u2014 nh 2 u2014 n c 1 c 6 2 u2014 nh c 1 c 6 u2014 n u2014 c o u2014 c 1 c 6 u2014 no 2 u2014 so 2 c 1 c 3 alkyl u2014 so 2 nh 2 u2014 so 2 nh c 1 c 3 alkyl u2014 so 2 n c 1 c 3 alkyl 2 u2014 cooh u2014 ch 2 u2014 cooh u2014 ch 2 u2014 n c 1 c 6 alkyl u2014 ch 2 u2014 n c 1 c 6 alkyl 2 u2014 ch 2 u2014 nh 2 pyridine r represents c 1 c 6 alkyl phenyl u2014 ch 2 o phenyl u2014 ch 2 o u2014 c 1 c 6 alkyl u2014 ch 2 phenyl u2014 ch 2 ch 2 phenyl or u2014 ch 2 phenyl cooz z represents h or c 1 c 6 alkyl and x represents a moiety selected from the group consisting of h f cl br c 1 c 10 alkyl c 3.