Pyrrolobenzodiazepines

A compound with the formula I:

• wherein:
• R2 is of formula II:
• where X is selected from the group comprising:
• OH, SH, CO2H, COH, N═C═O, NHNH2, CONHNH2,
• NHRN, wherein RN is selected from the group comprising H and C1-4 alkyl;
• RC1, RC2 and RC3 are independently selected from H and unsubstituted C1-2 alkyl;
• R12 is selected from the group consisting of:
• (ia) C5-10 aryl group, optionally substituted by one or more substituents selected from the group comprising:
• halo, nitro, cyano, ether, C1-7 alkyl, C3-7 heterocyclyl and bis-oxy-C1-3 alkylene;
• (ib) C1-5 saturated aliphatic alkyl;
• (ic) C3-6 saturated cycloalkyl;
• (id),
• wherein each of R21, R22 and R23 are independently selected from H, C1-3 saturated alkyl, C2-3 alkenyl, C2-3 alkynyl and cyclopropyl, where the total number of carbon atoms in the R12 group is no more than 5;
• (ie)
• wherein one of R25a and R25b is H and the other is selected from:
• phenyl, which phenyl is optionally substituted by a group selected from halo, methyl, methoxy;
• pyridyl;
• and thiophenyl;
• and
• (if)
• where R24 is selected from:
• H;
• C1-3 saturated alkyl;
• C2-3 alkenyl;
• C2-3 alkynyl;
• cyclopropyl;
• phenyl, which phenyl is optionally substituted by a group selected from halo, methyl, methoxy;
• pyridyl;
• and thiophenyl;
• R6 and R9 are independently selected from H, R, OH, OR, SH, SR, NH2, NHR, NRR′, nitro, Me3Sn and halo;
• where R and R′ are independently selected from optionally substituted C1-12 alkyl, C3-20 heterocyclyl and C5-20 aryl groups;
• R7 is selected from H, R, OH, OR, SH, SR, NH2, NHR, NHRR′, nitro, Me3Sn and halo;
• either:
• (a) R10 is H, and R11 is OH, ORA, where RA is C1-4 alkyl;
• (b) R10 and R11 form a nitrogen-carbon double bond between the nitrogen and carbon atoms to which they are bound;
• or
• (c) R10 is H and R11 is SOZM, where z is 2 or 3 and M is a monovalent pharmaceutically acceptable cation;
• R″ is a C3-12 alkylene group, which chain may be interrupted by one or more heteroatoms, and/or aromatic rings;
• Y and Y′ are selected from O, S, or NH;
• R6′, R7′, R9′ are selected from the same groups as R6, R7 and R9 respectively and R10′ and R11′ are the same as R10 and R11, wherein if R11 and R11′ are SOZM, M may represent a divalent pharmaceutically acceptable cation.

A compound of formula II:

• wherein:
• R2 is of formula II:
• where X is selected from the group comprising:
• OH, SH, CO2H, COH, N═C═O, NHNH2, CONHNH2,
• NHRN, wherein RN is selected from the group comprising H and C1-4 alkyl;
• RC1, RC2 and RC3 are independently selected from H and unsubstituted C1-2 alkyl;
• R12 is selected from the group consisting of:
• (ia) C5-10 aryl group, optionally substituted by one or more substituents selected from the group comprising:
• halo, nitro, cyano, ether, C1-7 alkyl, C3-7 heterocyclyl and bis-oxy-C1-3 alkylene;
• (ib) C1-5 saturated aliphatic alkyl;
• (ic) C3-6 saturated cycloalkyl;
• (id)
• wherein each of R21, R22 and R23 are independently selected from H, C1-3 saturated alkyl, C2-3 alkenyl, C2-3 alkynyl and cyclopropyl, where the total number of carbon atoms in the R12 group is no more than 5;
• (ie)
• wherein one of R25a and R25b is H and the other is selected from:
• phenyl, which phenyl is optionally substituted by a group selected from halo, methyl, methoxy;
• pyridyl;
• and thiophenyl;
• and
• (if)
• where R24 is selected from:
• H;
• C1-3 saturated alkyl;
• C2-3 alkenyl;
• C2-3 alkynyl;
• cyclopropyl;
• phenyl, which phenyl is optionally substituted by a group selected from halo, methyl, methoxy;
• pyridyl;
• and thiophenyl;
• R6 and R9 are independently selected from H, R, OH, OR, SH, SR, NH2, NHR, NRR′, nitro, Me3Sn and halo;
• where R and R′ are independently selected from optionally substituted C1-12 alkyl, C3-20 heterocyclyl and C5-20 aryl groups;
• R7 is selected from H, R, OH, OR, SH, SR, NH2, NHR, NHRR′, nitro, Me3Sn and halo;
• R″ is a C3-12 alkylene group, which chain may be interrupted by one or more heteroatoms, and/or aromatic rings;
• Y and Y′ are selected from O, S, or NH;
• R6′, R7′, R9′ are selected from the same groups as R6, R7 and R9 respectively;
• and either:
• (a) R10 is carbamate nitrogen protecting group, and R11 is O-ProtO, wherein ProtO is an oxygen protecting group;
• (b) R10 is a hemi-aminal nitrogen protecting group and R11 is an oxo group;
• and R10′ and R11′ are the same as R10 and R11.