Pyrrolobenzodiazepines

A compound with the formula I:

• wherein:
• R2 is of formula II′:
• where A is a C5-7 aryl group, X is selected from the group consisting of:
• OH, SH, CO2H, COH, N═C═O, NHNH2, CONHNH2,
• and NHRN, wherein RN is selected from H and C1-4 alkyl, and either:
• (i) Q1 is a single bond, and Q2 is selected from a single bond and —Z—(CH2)n—, where Z is selected from a single bond, O, S and NH and n is from 1 to 3;
• or
• (ii) Q1 is —CH═CH—, and Q2 is a single bond;
• R12 is selected from the group consisting of ═CH2, ═CHRD1 and ═CRD1RD2, where RD1 and RD2 are independently selected from R, CO2R, COR, CHO, CO2H, and halo;
• R6 and R9 are independently selected from the group consisting of:
• H, R, OH, OR, SH, SR, NH2, NHR, NRR′, nitro, Me3Sn and halo;
• R7 is selected from the group consisting of:
• H, R, OH, OR, SH, SR, NH2, NHR, NHRR′, 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;
• 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 is optionally interrupted by one or more heteroatoms, and/or aromatic rings;
• Y and Y′ are independently selected from the group consisting of O, S, and 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.