wherein: A is a ???(CH 2)m???, ???(CH 2)n ???X??? or ???(CH 2)v ???O??? group wherein m is an integer of 1 to 4, n is zero or an integer of 1 to 4, X is ???S??? or ???NH???, and v is zero or an integer of 1 to 5; s is 1 or 2; R is a phenyl ring optionally substituted by one or two substituents independently selected from halogen, cyano, C 1-C 4 alkyl, C 1-C 4 alkoxy and trifluoromethyl; R 1 is hyd