Pyrrolobenzodiazepines

A compound with the formula I:

• 36
• wherein:
• R10 is a therapeutically removable nitrogen protecting group;
• R2 and R3 are independently selected from:
• H, R, OH, OR, ═O, ═CH—R, ═CH2, CH2—CO2R, CH2—CO2H, CH2—SO2R, O—SO2—R, CO2R, COR and CN;
• R6, R7 and R9 are independently selected from H, R, OH, OR, halo, amino, nitro, Me3Sn;
• or R7 and R8 together form a group —O—(CH2)—O—, where p is 1 or 2.
• X is S, O or NH;
• R11 is either H or R;
• where R is a lower alkyl group having 1 to 10 carbon atoms, or an aralkyl group, of up to 12 carbon atoms, whereof the alkyl group optionally contains one or more carbon-carbon double or triple bonds, which may form part of a conjugated system, or an aryl group, of up to 12 carbon atoms;
• and is optionally substituted by one or more halo, hydroxy, amino, or nitro groups, and optionally contains one or more hetero atoms, which may form part of, or be, a functional group;
• and where there is optionally a double bond between C1 and C2 or C2 and C3;
• and R8 is selected from H, R, OH, OR, halo, amino, nitro, Me3Sn, where R is as defined above, or the compound is a dimer with each monomer being the same or different and being of formula I, where the R8 groups of the monomers form together a bridge having the formula -T-R′-T- linking the monomers, where R′ is an alkylene chain containing from 3 to 12 carbon atoms, which chain may be interrupted by one or more hetero atoms and/or aromatic rings, and may contain one or more carbon-carbon double or triple bonds, and each T is independently selected from O, S or N.