Patent ID: 7727979

Claim:
A compound of formula I wherein A is a three to six carbon atom chain, wherein (i) A does not comprise double bonds; and (ii) at least one of the carbon atoms of A is substituted by one or more: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 1,1-dimethylpropyl, allyl or cyclohex-1-enyl groups; or phenyl, O-tolyl, m-tolyl, p-tolyl, 2-ethylphenyl, 3-fluorophenyl, 4-fluorophenyl, 4-chlorophenyl, 4-cyanophenyl, 4-benzyloxyphenyl, 3-methoxyphenyl, 4-methoxyphenyl, 3,4-dimethoxyphenyl, 3,4-methylenedioxyphenyl or bis-3,5-trifluoromethylphenyl groups; or thiophene-2-yl or benzyl groups; or cyano or cyanoethyl groups; or pentamethylene groups linked at each end to a single carbon atom; or a pharmaceutically acceptable salt thereof.