Boron-containing small molecules
This invention relates to compounds useful for treating fungal infections, more specifically topical treatment of onychomycosis and/or cutaneous fungal infections. This invention is directed to compounds that are active against fungi and have properties that allow the compound, when placed in contact with a patient, to reach the particular part of the skin, nail, hair, claw or hoof infected by the fungus. In particular the present compounds have physiochemical properties that facilitate penetration of the nail plate.
1. A method of making a compound having a structure according to the following formula
wherein R 9a is H; R 10a is F; R 11a is H and R 12a is H; and R 1a is H;
said method comprising:
a) subjecting a first compound and a trialkyl borate to Grignard or organolithium conditions, said first compound having a structure according to the following formula:
b) quenching the product of step a) with water and an organic acid,
thereby forming said compound.
2. The method of claim 1 , wherein said organic acid is acetic acid.
3. The method of claim 1 , wherein said quenching step is essentially not contacted with a strong acid.
4. The method of claim 1 wherein said compound is purified by recrystallization from a recrystallization solvent, wherein said recrystallization solvent essentially does not contain acetonitrile.
5. The method of claim 4 , wherein said recrystallization solvent comprises toluene and heptane.
6. The method of claim 4 , wherein said recrystallization solvent contains a member selected from less than 2% acetonitrile, less than 1% acetonitrile, less than 0.5% acetonitrile, and less than 0.1% acetonitrile.
7. The method of claim 4 , wherein the recrystallization solvent contains toluene and a hydrocarbon solvent.
8. The method of claim 7 , wherein the recrystallization solvent contains a member selected from about 1:1 toluene:hydrocarbon solvent, about 2:1 toluene:hydrocarbon solvent, about 3:1 toluene:hydrocarbon solvent, and about 4:1 toluene:hydrocarbon solvent.
9. The method of claim 7 , wherein the hydrocarbon solvent is a member selected from heptane, octane, hexane, pentane and nonane.
10. The method of claim 5 , wherein the recrystallization solvent is 3:1 toluene:heptane.
11. The method of claim 1 wherein said trialkyl borate is a member selected from trimethyl borate, triisopropyl borate, and tributyl borate.
12. The method of claim 1 wherein said trialkyl borate is trimethyl borate.