Patent ID: 8202511

Claim:
Compounds of formula (I) and salts or optical active isomers thereof, wherein each R 1 independently are the same or different and denotes a hydrogen atom or a C 1 to C 4 straight or branched alkyl group which is optionally substituted by 1 to 4 —OH groups; each of R 2 independently are the same or different and denote a hydrogen atom or a C 1 to C 4 straight or branched alkyl group; each R 3 independently are the same or different and denotes a hydrogen atom or a C 1 to C 4 straight or branched alkyl group which is optionally substituted by 1 to 4 —OH groups; each R 4 independently are the same or different and denote C 1 to C 6 straight or branched alkyl moieties substituted by up to 6 —OH groups; and each R 5 independently are the same or different and denote C 1 to C 6 straight or branched alkyl moieties substituted by up to 6 —OH groups; and X denotes a 1,4-cyclohexylene group, or X together with the adjacent —NR 1 groups forms a 1,4-piperazine group or a 4-aminopiperidine group.