Retinoid derivatives with antitumor activity

A compound:

• (a) having the following formula (I):
• wherein:
• A is selected from the group consisting of:
• alkylene, alkenylene, alkynylene, and COalkylene, or A is absent,
• R1 is selected from the group consisting of:
• CONHOH, CH2OH, CH2SH, CH2SCOCH3, CH2NHOH, COOH, COO-alkyl, COCF3, CONHOalkyl, CONHO-oxacycloalkyl, CONHNH2, and CONH-aryl,
• wherein said aryl is optionally substituted with OH and/or NH2, or the aryl comprises CONHalkyl-S—S-alkyl, or CONHalkyl-S—S-alkyl-NH2, or the aryl comprises CONHalkyl-S—S-alkyl-NHCO—C(═NOH)alkylaryl,
• wherein said aryl is optionally substituted with OH and/or halogen, or the aryl comprises COalkylCONHalkyl-S—S-alkyl-NHCO—C(═NOH)alkylaryl,
• wherein said aryl is optionally substituted with OH and/or halogen,
• R2 is selected from the group consisting of:
• H, alkyl, OH, O-alkyl, O-alkenyl, halogen, CN, CHO, COalkyl, COOH, COOalkyl and CONH2,
• R3 is selected from the group consisting of:
• H, alkyl, alkenyl, oxo-alkenyl, hydroxyiminoalkenyl, OH, alkoxy, cycloalkyloxy, arylalcoxy, heterocycloalcoxy, carboxyalcoxy, CH2R6, COR7, CN, CH═NOH, CH═NOalkylCOOH, CH═NOaryl and CH═NOalkylaryl,
• wherein R6 is selected from the group consisting of:
• OH, alkoxy, NH2, NH-alkyl, N-dialkyl, NHCOOalkyl, NHCOalkyl, aryl, heterocycloalkyl, guanidino optionally substituted with an alkyl or a COOalkyl group, biguanido optionally substituted with an alkyl or an arylalkyl group, and NH—SO2-aryl,
• and wherein R7 is selected from the group consisting of:
• H, OH, O-alkyl, NH2, NHOH, NHaryl, and NHalkyl optionally terminally substituted with NH2 or CONHOH,
• R4 is selected from the group consisting of:
• OH, O-alkyl, NH2, NHaryl, NHalkyl, Ndialkyl, NHOH, NHNH2 and CF3, and
• R5 is selected from the group consisting of:
• H, alkyl, cycloalkyl, azacycloalkyl, oxacycloalkyl, aryl, heteroaryl, alkylamminomethyl, arylakylaminomethyl, heteroarylalkylaminomethyl, wherein each of said groups can be optionally substituted with one or more substituents selected from the group consisting of OH, alkyl, Oalkyl, halogen, NO2, NH2, NHalkyl, Ndialkyl, pyrrolidine, piperidine and morpholine, provided that when R5 is H R1 is CONHOH,
• R8 and R9 are H or together with the carbon atoms to which they are bound form a fused five- or six-membered aromatic or heteroaromatic ring,
• wherein alkyl is a C1-C20 linear or branched alkyl group,
• alkenyl is a C2-C20 linear or branched alkyl group,
• cycloalkyl is a saturated or partially unsaturated C3-C10 carbocyclic group comprising one or more condensed rings,
• aryl is an aromatic group comprising one or more condensed aromatic rings,
• heterocycloalkyl and heteroaryl are said cycloalkyl or aryl rings containing one or more heteroatoms selected from the group consisting of N, O and S,
• said cycloalkyl, heterocycloalkyl, aryl, heteroaryl, aromatic or heteroaromatic ring being optionally substituted on any position of the ring with one or more substituents selected from the group consisting of halogen, alkyl, linear or branched, O-alkyl, linear or branched, amino, cycloalkyl, heterocycloalkyl, carboxyl, NO2, NH2 and OH,
• amino is a group NR′R″ wherein each of R′ and R″ can independently be H or alkyl,
• (b) that is an enantiomer or a diastereoisomer of the compound of (a), or
• (c) that is a pharmaceutically acceptable salt, hydrate or solvate of a compound of (a) or (b).