Chemiluminescent probes for diagnostics and in vivo imaging

1. A compound of the formula IVa or IVb:

wherein

R 1 is selected from the group consisting of a linear or branched (C 1 -C 18 )alkyl, and (C 3 -C 7 )cycloalkyl;

R 2 and R 3 each independently is selected from the group consisting of a branched (C 3 -C 18 )alkyl and (C 3 -C 7 )cycloalkyl, or R 2 and R 3 together with the carbon atom to which they are attached form a fused, spiro or bridged cyclic or polycyclic ring;

R 4 is H, or a caging 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 (C 1 -C 18 )alkyl and (C 3 -C 7 )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 R 4 is 4,4,5,5-tetramethyl-1,3,2-dioxaborolanyl or —B(OH) 2 , and when R 4 is H, L is absent;

Y is absent or is —O—, provided that Y is —O— unless R 4 is 4,4,5,5-tetramethyl-1,3,2-dioxaborolanyl or —B(OH) 2 , and L is absent;

R 7 is H, or represents at least one electron acceptor group selected from the group consisting of halogen, —NO 2 , —CN, —COOR 10 , —C(═O)R 10 and —SO 2 R 10 , each independently attached either ortho or para to the —Y-L-R 4 group;

R 10 each independently is H or —(C 1 -C 18 )alkyl; and

A is a π* acceptor group of the formula —CH═CH-E, attached either ortho or para to the —Y-L-R 4 group, wherein E is —CN, —COOH, —COO(C 1 -C 18 )alkyl, 4-pyridinyl, methylpyridinium-4-yl, 3,3-dimethyl-3H-indolyl, or 1,3,3-trimethyl-3H-indol-1-ium-2-yl.

2. The compound of claim 1 , wherein:

(i) R 1 is a linear or branched (C 1 -C 8 )alkyl; or

(ii) R 2 and R 3 together with the carbon atom to which they are attached form a fused, spiro or bridged polycyclic ring; or

(iii) said caging group is selected from the group consisting of:

wherein Pep is a peptide consisting of at least two amino acid residues and linked via a carboxylic group thereof; or

(iv) R 7 is H, or an electron acceptor group selected from the group consisting of halogen and —CN, attached either ortho or para to the —Y-L-R 4 group; or

(v) A is —CH═CH-E attached ortho to the —Y-L-R 4 group, wherein E is —CN, —COOH, —COO(C 1 -C 8 )alkyl, 4-pyridinyl, methylpyridinium-4-yl, 3,3-dimethyl-3H-indolyl, or 1,3,3-trimethyl-3H-indol-1-ium-2-yl.

3. The compound of claim 2 , wherein R 2 and R 3 together with the carbon atom to which they are attached form adamantyl.

4. The compound of claim 2 , wherein R 7 is halogen or —CN, attached ortho to the —Y-L-R 4 group.

5. The compound of claim 2 , wherein E is —CN, —COOH, or —COO(C 1 -C 4 )alkyl.

6. The compound of claim 1 , wherein:

R 1 is a linear or branched (C 1 -C 8 )alkyl;

R 2 and R 3 together with the carbon atom to which they are attached form a fused, spiro or bridged polycyclic ring;

R 7 is H, or an electron acceptor group selected from the group consisting of halogen and —CN, attached either ortho or para to the —Y-L-R 4 group; and

A is —CH═CH-E attached ortho to the —Y-L-R 4 group, wherein E is —CN, —COOH, —COO(C 1 -C 8 )alkyl, 4-pyridinyl, methylpyridinium-4-yl, 3,3-dimethyl-3H-indolyl, or 1,3,3-trimethyl-3H-indol-1-ium-2-yl.

7. The compound of claim 6 , wherein R 1 is methyl; R 2 and R 3 together with the carbon atom to which they are attached form adamantyl; R 7 is H, or is an electron acceptor group selected from the group consisting of halogen and —CN, attached ortho to the —Y-L-R 4 group; and E is —CN, —COOH, or —COO(C 1 -C 4 )alkyl.

8. The compound of claim 7 , wherein E is —CN, —COOH, —COOCH 3 , or —COOC(CH 3 ) 3 .

9. The compound claim 1 , wherein (i) Y is —O—; L is absent; and R 4 is H; (ii) Y is —O—; L is absent; and R 4 is phosphonate; (iii) Y is —O—, L is absent or a linker of the formula L1, L2 or L3, wherein M is —O— or —NH—, and R 4 is a caging group; or (iv) Y is absent, L is absent, and R 4 is 4,4,5,5-tetramethyl-1,3,2-dioxaborolanyl or —B(OH) 2 .

10. The compound of claim 9 , wherein R 1 is methyl; R 2 and R 3 together with the carbon atom to which they are attached form adamantyl; R 7 is H, or Cl attached ortho to the —Y-L-R 4 group; A is —CH═CH-E attached ortho to the —Y-L-R 4 group; and:

(i) E is —COOC(CH 3 ) 3 ; Y is —O—; L is absent; and R 4 is galactosyl;

(ii) E is —COOCH 3 or —CN; Y is —O—; L is absent; and R 4 is H;

(iii) E is —COOCH 3 or —CN; Y is —O—; L is L1 wherein M is —O—; and R 4 is galactosyl;

(iv) E is —COOCH 3 ; Y is —O—; L is L1 wherein M is —NH—; and R 4 is 2,4-dinitrobenzene sulfonate;

(v) E is —COOH; Y is absent; L is absent; and R 4 is 4,4,5,5-tetramethyl-1,3,2-dioxaborolanyl; or

(vi) E is —COOH; Y is —O—; L is absent; and R 4 is H or phosphonate.

11. The compound of claim 10 , selected from the group consisting of compounds IVa-1, IVa-2, IVa-3, IVa-4, IVa-5, IVa-6, IVa-7, IVa-8, IVa-9, IVa-10, IVa-11, IVa-12, IVa-13, IVa-14, IVa-15, IVa-16, IVb-1, IV-2, IVb-3, IV-4, IVb-5, IV-6, IVb-7, IVb-8, IVb-9, IV-10, IV-11, IV-12, IV-13, IV-14, IV-15, and IVb-16:

12. A composition comprising a carrier, and a compound according to claim 1 .

13. A method for diagnostics or in vivo imaging comprising:

applying a composition according to claim 12 to a biological tissue or administering a composition according to claim 12 to a subject, wherein R 4 of the compound of formula IVa/IVb is a caging group cleavable by an analyte, wherein upon exposure to said analyte, group R 4 is cleaved from the compound of formula IVa/IVb, thereby generating an unstable phenolate-dioxetane compound, which is then decomposed through a chemiexcitation process to produce an excited intermediate that decays to its ground-state through emission of light; and imaging to detect the emission of light.

14. The compound of claim 9 , wherein R 1 is methyl; R 2 and R 3 together with the carbon atom to which they are attached form adamantyl; R 7 is Cl attached ortho to the —Y-L-R 4 group; A is —CH═CH-E attached ortho to the —Y-L-R 4 group; E is —COOH; Y is —O—; L is absent; and R 4 is H, of the formula: