A compound of the formula(see formula I)or a pharmaceutically acceptable salt thereof;whereinY is-CO2(CH2)2OH or (see formula II)A is -(CH2)6-, cis-CH2CH=CH-(CH2)3-, or -CH2C.ident.C-(CH2)3-, wherein 1 or 2carbon atoms maybe replaced by S or O; or A is -(CH2)m-Ar-(CH2)o- wherein Ar is interaryleneorheterointerarylene, the sum of m and o is 1, 2, 3, or 4, and wherein 1 -CH2-may be replaced by Sor O, and 1-CH2-CH2 may be replaced by -CH=CH- or C.ident.C; andB is aryl or heteroaryl.