Patent ID: 8692000

Claim:
A compound of formula (I): wherein each of R 1 and R 8 , independently, is C 1 -C 10 alkyl, C 3 -C 20 cycloalkyl, C 3 -C 20 heterocycloalkyl, aryl, or heteroaryl; or R 1 and R 8 form C 1 -C 10 alkyl, C 3 -C 20 cycloalkyl, C 3 -C 20 heterocycloalkyl, aryl, or heteroaryl; each of R 2 , R 3 , R 6 , and R 7 , independently, is H, C 1 -C 10 alkyl, C 3 -C 20 cycloalkyl, C 3 -C 20 heterocycloalkyl, aryl, or heteroaryl; or R 2 and R 3 , together with the two carbon atoms to which they are attached, form C 4 -C 20 cycloalkyl, C 4 -C 20 heterocycloalkyl, aryl, or heteroaryl; or R 6 and R 7 , together with the two carbon atoms to which they are attached, form C 4 -C 20 cycloalkyl, C 4 -C 20 heterocycloalkyl, aryl, or heteroaryl; each of R 4 and R 5 , independently, is C 1 -C 10 alkyl, C 3 -C 20 cycloalkyl, C 3 -C 20 heterocycloalkyl, aryl, or heteroaryl; X − is a halide ion, a hydroxide ion, a tetrafluoroboric acid ion, a nitric acid ion, a hexaflorophosphoric acid ion, a tetrakis(3,5-bis(trifluoromethyl)phenyl)boronic acid ion, a sulfuric acid ion, a phosphoric acid ion, a citric acid ion, a methanesulfonic acid ion, a trifluoroacetic acid ion, a malic acid ion, a tartaric acid ion, a fumaric acid ion, a glutamic acid ion, a glucuronic acid ion, a lactic acid ion, a glutaric acid ion, a maleic acid ion, an acetic acid ion, or a p-toluenesulfonic acid ion; and at least one of the four carbon atoms to which R 2 , R 3 , R 6 , and R 7 are attached has an R or S configuration.