Fused cyclooctyne compounds and their use in metal-free click reactions

1. A compound of the Formula (IIa):

wherein:

n is 0 to 8;

p is 0 or 1;

R 3 is selected from the group consisting of [(L) p -Q], hydrogen, halogen, C 1 -C 24 alkyl groups, C 6 -C 24 (hetero)aryl groups, C 7 -C 24 alkyl(hetero)aryl groups and C 7 -C 24 (hetero)arylalkyl groups, the alkyl groups optionally being interrupted by one of more hetero-atoms selected from the group consisting of O, N and S, wherein the alkyl groups, (hetero)aryl groups, alkyl(hetero)aryl groups and (hetero)arylalkyl groups are independently optionally substituted with one or more substituents independently selected from the group consisting of C 1 -C 12 alkyl groups, C 2 -C 12 alkenyl groups, C 2 -C 12 alkynyl groups, C 3 -C 12 cycloalkyl groups, C 1 -C 12 alkoxy groups, C 2 -C 12 alkenyloxy groups, C 2 -C 12 alkynyloxy groups, C 3 -C 12 cycloalkyloxy groups, halogens, amino groups, oxo groups and silyl groups, wherein the alkyl groups, alkenyl groups, alkynyl groups, cycloalkyl groups, alkoxy groups, alkenyloxy groups, alkynyloxy groups and cycloalkyloxy groups are optionally substituted, the alkyl groups, the alkoxy groups, the cycloalkyl groups and the cycloalkoxy groups being optionally interrupted by one of more hetero-atoms selected from the group consisting of O, N and S, wherein the silyl groups are represented by the formula (R 4 ) 3 Si—, wherein R 4 is independently selected from the group consisting of C 1 -C 12 alkyl groups, C 2 -C 12 alkenyl groups, C 2 -C 12 alkynyl groups, C 3 -C 12 cycloalkyl groups, C 1 -C 12 alkoxy groups, C 2 -C 12 alkenyloxy groups, C 2 -C 12 alkynyloxy groups and C 3 -C 12 cycloalkyloxy groups, wherein the alkyl groups, alkenyl groups, alkynyl groups, cycloalkyl groups, alkoxy groups, alkenyloxy groups, alkynyloxy groups and cycloalkyloxy groups are optionally substituted, the alkyl groups, the alkoxy groups, the cycloalkyl groups and the cycloalkoxy groups being optionally interrupted by one of more hetero-atoms selected from the group consisting of O, N and S;

L is a linking group selected from linear or branched C 1 -C 24 alkylene groups, C 2 -C 24 alkenylene groups, C 2 -C 24 alkynylene groups, C 3 -C 24 cycloalkylene groups, C 5 -C 24 cycloalkenylene groups, C 8 -C 24 cycloalkynylene groups, C 7 -C 24 alkyl(hetero)arylene groups, C 7 -C 24 (hetero)arylalkylene groups, C 8 -C 24 (hetero)arylalkenylene groups, C 9 -C 24 (hetero)arylalkynylene groups, the alkylene groups, alkenylene groups, alkynylene groups, cycloalkylene groups, cycloalkenylene groups, cycloalkynylene groups, alkyl(hetero)arylene groups, (hetero)arylalkylene groups, (hetero)arylalkenylene groups and (hetero)arylalkynylene groups optionally being substituted with one or more substituents independently selected from the group consisting of C 1 -C 12 alkyl groups, C 2 -C 12 alkenyl groups, C 2 -C 12 alkynyl groups, C 3 -C 12 cycloalkyl groups, C 5 -C 12 cycloalkenyl groups, C 8 -C 12 cycloalkynyl groups, C 1 -C 12 alkoxy groups, C 2 -C 12 alkenyloxy groups, C 2 -C 12 alkynyloxy groups, C 3 -C 12 cycloalkyloxy groups, halogens, amino groups, oxo and silyl groups, wherein the silyl groups can be represented by the formula (R 4 ) 3 Si—, wherein R 4 is defined as above;

Q is a functional group selected from the group consisting of hydrogen, halogen, R 6 , —CH═C(R 6 ) 2 , —C≡CR 6 , —[C(R 6 ) 2 C(R 6 ) 2 O] q —R 6 , wherein q is in the range of 1 to 200, —CN, —N 3 , —NCX, —XCN, —XR 6 , —N(R 6 ) 2 , — + N(R 6 ) 3 , —C(X)N(R 6 ) 2 , —C(R 6 ) 2 XR 6 , —C(X)R 6 , —C(X)XR 6 , —S(O)R 6 , —S(O) 2 R 6 , —S(O)OR 6 , —S(O) 2 OR 6 , —S(O)N(R 6 ) 2 , —S(O) 2 N(R 6 ) 2 , —OS(O)R 6 , —OS(O) 2 R 6 , —OS(O)OR 6 , —OS(O) 2 OR 6 , —P(O)(R 6 )(OR 6 ), —P(O)(OR 6 ) 2 , —OP(O)(OR 6 ) 2 , —Si(R 6 ) 3 , —XC(X)R 6 , —XC(X)XR 6 , —XC(X)N(R 6 ) 2 , —N(R 6 )C(X)R 6 , —N(R 6 )C(X)XR 6 and —N(R 6 )C(X)N(R 6 ) 2 , wherein X is oxygen or sulphur and wherein R 6 is independently selected from the group consisting of hydrogen, halogen, C 1 -C 24 alkyl groups, C 6 -C 24 (hetero)aryl groups, C 7 -C 24 alkyl(hetero)aryl groups and C 7 -C 24 (hetero)arylalkyl groups;

R 1 is independently selected from the group consisting of hydrogen, C 1 -C 24 alkyl groups, C 6 -C 24 (hetero)aryl groups, C 7 -C 24 alkyl(hetero)aryl groups and C 7 -C 24 (hetero)arylalkyl groups; and

R 2 is independently selected from the group consisting of halogen, —OR 6 , —NO 2 , —CN, —S(O) 2 R 6 , C 1 -C 12 alkyl groups, C 1 -C 12 aryl groups, C 1 -C 12 alkylaryl groups and C 1 -C 12 arylalkyl groups, wherein R 6 is as defined above, and wherein the alkyl groups, aryl groups, alkylaryl groups and arylalkyl groups are optionally substituted.

2. The compound according to claim 1 , wherein n is 0.

3. The compound according to claim 1 , wherein p is 1 and L is CH 2 .

4. The compound according to claim 1 , wherein Q is selected from the group consisting of —OR 6 , —N(R 6 ) 2 , — + N(R 6 ) 3 , —C(O)N(R 6 ) 2 , —C(O)OR 6 , —OC(O)R 6 , —OC(O)OR 6 , —OC(O)N(R 6 ) 2 , —N(R 6 )C(O)R 6 , —N(R 6 )C(O)OR 6 and —N(R 6 )C(O)N(R 6 ) 2 , wherein R 6 is as defined in claim 1 .

5. The compound according to claim 1 , wherein Q is —OH.

6. The compound according to claim 1 , wherein R 1 is hydrogen.

7. The compound according to claim 1 , wherein R 3 is hydrogen or [(L) p -Q].

8. The compound according to claim 1 , wherein p is 1, L is CH 2 , Q is —OH, R 1 is hydrogen and R 3 is hydrogen or [(L) p -Q].

9. The compound according to claim 2 , wherein p is 1, L is CH 2 , Q is —OH, R 1 is hydrogen, and R 3 is hydrogen or [(L) p -Q].

10. A conjugate comprising a compound according to claim 1 conjugated to a label via a functional group Q, wherein the label is selected from the group comprising of fluorophores, biotin, polyethylene glycol chains, polypropylene glycol chains, mixed polyethylene/polypropylene glycol chains, radioactive isotopes, steroids, pharmaceutical compounds, lipids, peptides, glycans, nucleotides and peptide tags.

11. A method for preparing a compound according to claim 1 , the method comprising:

(a) Cyclopropanation of a cyclooctadiene of the Formula (VIIa):

wherein:

n=0 to 8;

R 1 is independently selected from the group consisting of hydrogen, C 1 -C 24 alkyl groups, C 6 -C 24 (hetero)aryl groups, C 7 -C 24 alkyl(hetero)aryl groups and C 7 -C 24 (hetero)arylalkyl groups; and

R 2 is independently selected from the group consisting of halogen, —OR 6 , —NO 2 , —CN, —S(O) 2 R 6 , C 1 -C 12 alkyl groups, C 1 -C 12 aryl groups, C 1 -C 12 alkylaryl groups and C 1 -C 12 arylalkyl groups, wherein the alkyl groups, aryl groups, alkylaryl groups and arylalkyl groups are optionally substituted, and wherein R 6 is independently selected from the group consisting of hydrogen, halogen, C 1 -C 24 alkyl groups, C 6 -C 24 (hetero)aryl groups, C 7 -C 24 alkyl(hetero)aryl groups and C 7 -C 24 (hetero)arylalkyl groups,

to form a bicyclic cyclooctene compound,

(b) Bromination of the obtained bicyclic cyclooctene compound to form a bicyclic cyclooctane compound, and

(c) Dehydrobromination of the obtained bicyclic cyclooctane compound to form a compound according to claim 1 .

12. A method for the modification of a target molecule, comprising reacting a conjugate according to claim 10 with a compound comprising a 1,3-dipole or a 1,3-(hetero)diene.

13. The method according to claim 12 , wherein the compound comprising a 1,3-dipole is an azide-comprising compound, a nitrone-comprising compound, or a nitrile oxide-comprising compound.

14. A composition comprising a conjugate according to claim 10 and a pharmaceutically acceptable carrier.

15. The compound according to claim 2 , wherein p is 1 and L is CH 2 .

16. The compound according to claim 2 , wherein Q is selected from the group consisting of —OR 6 , —N(R 6 ) 2 , — + N(R 6 ) 3 , —C(O)N(R 6 ) 2 , —C(O)OR 6 , —OC(O)R 6 , —OC(O)OR 6 , —OC(O)N(R 6 ) 2 , —N(R 6 )C(O)R 6 , —N(R 6 )C(O)OR 6 and —N(R 6 )C(O)N(R 6 ) 2 , wherein R 6 is independently selected from the group consisting of hydrogen, halogen, C 1 -C 24 alkyl groups, C 6 -C 24 (hetero)aryl groups, C 2 -C 24 alkyl(hetero)aryl groups and C 2 -C 24 (hetero)arylalkyl groups.

17. The compound according to claim 2 , wherein Q is —OH.

18. The compound according to claim 2 , wherein R 1 is hydrogen.

19. The compound according to claim 2 , wherein R 3 is hydrogen or [(L) p -Q].

20. The compound according to claim 18 , wherein R 3 is hydrogen or [(L) p -Q].

21. The compound according to claim 9 , wherein R 3 is hydrogen.

22. The compound according to claim 9 , wherein R 3 is [(L) p -Q] and wherein p is 1, L is CH 2 and Q is OH.

23. The compound according to claim 21 , wherein the compound is of the Formula (exo-IIa.2) or (endo-IIa.2):

24. The compound according to claim 22 , wherein the compound is of the Formula (IIa.7):