Alkylated photoremovable protecting groups and uses thereof

1. A compound of the formula A-G or A-L-G, wherein:

G is an organic or inorganic compound photoreleasably linked to the moiety A, wherein G is photoreleasable from moiety A at wavelengths of >500 nm, wherein L, when present, is a linking group; and

A is of the formula I:

and salts thereof;

wherein:

the wavy line represents the attachment point of the moiety A to the moiety G or L-G at a heteroatom in G or L-G that is N, O, or Cl;

R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 are each, independently, hydrogen, optionally substituted C 1 -C 6 -alkyl, optionally substituted C 2 -C 6 -alkenyl or (C 6 -C 14 -aryl)-(C 2 -C 6 -alkenyl-), wherein the (C 6 -C 14 -aryl)-(C 2 -C 6 -alkenyl-) is optionally substituted on the C 2 -C 6 -alkenyl or the C 6 -C 14 -aryl; and

R 7 and R 8 are each, independently, optionally substituted C 1 -C 6 -alkyl, optionally substituted C 2 -C 6 -alkenyl or optionally substituted C 6 -C 14 -aryl; or

A is of formula II:

and salts thereof,

wherein:

the wavy line represents the attachment point of the moiety A to the moiety G or L-G at a heteroatom in G or L-G that is N, O, or Cl; R 1a , R 2a , R 3a , R 4a , R 5a , and R 6a are each, independently, hydrogen, acyl, carboxy, optionally substituted C 1 -C 6 -alkyl, optionally substituted C 1 -C 6 -alkoxy, amino, optionally substituted C 2 -C 6 -alkenyl, optionally substituted C 6 -C 14 -aryl, optionally substituted C 2 -C 8 -heterocyclyl, or optionally substituted C 2 -C 8 -heterocyclyl-(C 2 -C 6 -alkenyl-), wherein the (C 2 -C 8 -heterocyclyl)-(C 2 -C 6 -alkenyl-) is optionally substituted on the C 2 -C 6 -alkenyl or the C 2 -C 8 -heterocyclyl, or R 1a and R 2a , R 2a and R 3a , R 4a and R 5a or R 5a and R 6a , together with the carbon atoms to which they are attached, form an optionally substituted C 2 -C 8 -heterocyclyl or an optionally substituted C 6 -C 14 -aryl, and R 7 and R 8 are each, independently, optionally substituted C 1 -C 6 -alkyl, optionally substituted C 2 -C 6 -alkenyl or optionally substituted C 6 -C 14 -aryl.

2. The compound of claim 1 , wherein A is of formula II, wherein R 1a and R 4a are each independently selected from an optionally substituted C 1 -C 6 -alkyl and an optionally substituted C 2 -C 6 -alkenyl.

3. The compound of claim 2 , wherein A is of formula II, wherein R 1a and R 4a are each methyl or —CH—CH-Ph-4-OMe.

4. The compound of claim 1 , wherein A is of formula II, wherein R 3a and R 6a are each, independently, an optionally substituted C 1 -C 6 -alkyl.

5. The compound of claim 4 , wherein A is of formula II, wherein R 3a and R 6a are each methyl.

6. The compound of claim 1 , wherein A is of formula II, wherein R 2a and R 5a are each hydrogen.

7. The compound of claim 1 , wherein A is of formula II, wherein R 7 and R 8 are each, independently, methyl or phenyl.

8. The compound of claim 1 , wherein A is of formula II, wherein at least one of R 1a , R 3a , R 4a , and R 6a is C 2 -C 8 -heterocyclyl-(C 2 -C 6 -alkenyl-).

9. The compound of claim 1 , wherein A is of formula II, wherein at least one of R 1a and R 4a is C 2 -C 8 -heterocyclyl.

10. The compound of claim 1 , wherein A is of formula II, wherein the moiety A is a moiety of the formula:

11. The compound of claim 1 , wherein A is of formula II, wherein the moiety A is a moiety of the formula:

wherein R 11 -R 14 are each independently H, halo, nitro, cyano, acyl, C 1 -C 6 -alkyl, C 1 -C 6 -alkoxy, amino or —[O—R 9 -] p O—R 10 , wherein R 9 is alkylenyl or cycloalkylenyl, R 10 is alkyl, and p is an integer from 1 to 10; and R 15 and R 16 are each H or C 1 -C 6 -alkyl.

12. The compound of claim 1 , wherein A is of formula II, wherein A is a moiety of formula:

wherein R 15 is H or C 1 -C 6 -alkyl.

13. The compound of claim 1 , wherein A is of formula II, wherein A is a moiety of formula:

wherein R 11 -R 14 are each independently H, halo, nitro, cyano, acyl, C 1 -C 6 -alkyl, C 1 -C 6 -alkoxy, amino or —[O—R 9 -] p O—R 10 , wherein R 9 is alkylenyl or cycloalkylenyl, R 10 is alkyl, and p is an integer from 1 to 10; and R 15 and R 16 are each H or C 1 -C 6 -alkyl.

14. The compound of claim 1 , wherein L is a linking group selected from the group consisting of acylalkylacyloxy, acylalkyloxy, (poly)alkylene glycol aminoalkylamino, aminoalkyloxy, and acylalkylamino, wherein the “alkyl” in acylalkylacyloxy, acylalkyloxy, (poly)alkylene glycol, aminoalkylamino, aminoalkyloxy, and acylalkylamino is optionally substituted.

15. The compound of claim 1 , wherein the compound of the formula A-G or A-L-G has a wavelength absorption maximum, λ max , between about 510 nm to about 1000 nm.

16. The compound of claim 1 , wherein the compound of the formula A-G or A-L-G has an extinction coefficient measured at the compound of formula A-G λ max or the compound of formula A-L-G λ max of from about 4.0×10 4 M −1 cm −1 to about 8.0×10 4 M −1 cm −1 .

17. The compound of claim 1 , wherein the moiety G comprises at least one of a protein, an oligopeptide, an amino acid, an oligonucleotide, an ion, and a small molecule.

18. The compound of claim 17 , wherein G comprises a protein and the protein comprised in the moiety G is selected from the group consisting of caspases, phosphatases, cholinesterases, esterases, transferases, restriction endonucleases, and hemoglobin.

19. The compound of claim 17 , wherein the small molecule comprised in the moiety G is at least one of a dye, fragrance, nucleoside, nucleotide, neurotransmitter, and pharmaceutical agent.

20. The compound of claim 19 , wherein G comprises a nucleoside and the nucleoside comprised in the moiety G is adenine, thymidine, cytosine, guanosine or uridine.

21. The compound of claim 19 , wherein G comprises a nucleotide and the nucleotide comprised in the moiety G is adenosine triphosphate (ATP) or guanosine triphosphate (GTP).

22. The compound of claim 19 , wherein G comprises a neurotransmitter and the neurotransmitter comprised in the moiety G is norepinephrine, glutamate, dopamine, gamma-aminobutyric acid, serotonin or an endorphin.

23. The compound of claim 1 , wherein the moiety G is a moiety of the formula —O-G′, wherein G′ is at least one of a protein, an oligonucleotide, a polynucleotide, an ion, and a small molecule.

24. A method for photoreleasing a moiety G, or a fragment thereof, from a compound of the formula A-G of claim 1 , comprising:

irradiating a composition comprising the compound of the formula A-G at a wavelength of >500 nm, so as to photorelease the moiety G, or a fragment thereof, from the moiety A.

25. A method for photoreleasing a moiety L-G, or a fragment thereof, from a compound of the formula A-L-G of claim 1 , the method comprising:

irradiating a composition comprising the compound of the formula A-L-G at a wavelength of >500 nm, so as to photorelease the moiety L-G, or a fragment thereof, from the moiety A;

wherein the moiety L-G, or fragment thereof, comprises an organic compound.

26. A compound of the formula A-G or A-L-G, wherein:

G is an organic or inorganic compound photoreleasably linked to the moiety A, wherein G is photoreleasable from moiety A at wavelengths of >500 nm, wherein L, when present, is a linking group; and

or salts thereof;

wherein:

the wavy line represents the attachment point of the moiety A to the moiety G or L-G at a heteroatom in G or L-G that is N, O, or Cl.