Chemiluminescent probes for diagnostics and in vivo imaging

A compound of the formula IIa or IIb:

• wherein
• R1 is selected from the group consisting of a linear or branched (C1-C15)alkyl, and (C3-C7)cycloalkyl;
• R2 and R3 each independently is selected from the group consisting of a branched (C3-C15)alkyl and (C3-C7)cycloalkyl, or R2 and R3 together with the carbon atom to which they are attached form a fused, spiro or bridged cyclic or polycyclic ring;
• R4 is a protecting group:
• L is absent or is a linker of the formula L1, L2 or L3, optionally substituted at the aromatic ring with one or more substituents each independently selected from the group consisting of (C1-C18)alkyl and (C3-C7)cycloalkyl, wherein M is absent or is —O— or —NH—, and the asterisk represents the point of attachment to the group Y, provided that M is —O— or —NH— unless R4 is 4,4,5,5-tetramethyl-1,3,2-dioxaborolanyl or —B(OH)2;
• Y is absent or is —O—, provided that Y is —O— unless R4 is 4,4,5,5-tetramethyl-1,3,2-dioxaborolanyl or —B(OH)2, and L is absent;
• R7, R8 and R9 each independently is H, or an electron acceptor group selected from the group consisting of halogen, —NO2, —CN, —COOR10, —C(═O)R10 and —SO2R10;
• R10 each independently is H or —(C1-C18)alkyl;
• X is a linker of the formula —X1-X2—, wherein X1 is selected from the group consisting of (C1-C18)alkylene, (C2-C18)alkenylene, (C2-C18)alkynylene, (C3-C7)cycloalkylene, (C3-C7)cycloalkenylene, (C6-C14)arylene-diyl, (C1-C18)alkylene-(C6-C14)arylene-diyl, heteroarylenediyl, and (C1-C18)alkylene-heteroarylenediyl, said (C1-C18)alkylene, (C2-C18)alkenylene, (C2-C18)alkynylene, (C3-C7)cycloalkylene, (C3-C7)cycloalkenylene, (C6-C14)arylene-diyl, or heteroarylenediyl being optionally substituted by one or more groups each independently selected from the group consisting of halogen, —COR10, —COOR10, —OCOOOR10, —OCON(R10)2, —CN, —NO2, —SR10, —OR10, —N(R10)2, —CON(R10)2, —SO2R10, —SO3H, —S(═O)R10, (C6-C10)aryl, (C1-C4)alkylene-(C6-C10)aryl, heteroaryl, and (C1-C4)alkylene-heteroaryl, and said (C1-C18)alkylene, (C2-C18)alkenylene, or (C2-C18)alkynylene being further optionally interrupted by one or more identical or different heteroatoms selected from the group consisting of S, O and N, and/or at least one group each independently selected from the group consisting of —NH—CO—, —CO—NH—, —N(C1-C8alkyl)-, —N(C6-C10aryl)-, (C6-C10)arylene-diyl, and heteroarylenediyl;
• and λ2 is absent or is —C(O)—;
• and
• R14 is a reactive group such as —O—(C1-C18)alkyl, —N3, —C—CH, N-succinimidyloxy, 3-sulfo-N-succinimidyloxy, pentafluorophenyloxy, 4-nitrophenyloxy, N-imidazolyl, and N-1H-benzo[d][1,2,3]triazoloxy.