Patent ID: 7741513

Claim:
A composition comprising a compound of formula I or a salt thereof, wherein R 1 , R 2 , and R 3 are each independently (C 1 -C 6 )alkyl, (C 3 -C 6 )cycloalkyl, (C 1 -C 6 )alkoxy, aryl, aryloxy, aryl(C 1 -C 3 )alkyl, aryl(C 1 -C 3 )alkoxy, wherein any cycloalkyl, alkyl, or aryl group is optionally substituted with one or more halo, oxo, hydroxy, methoxy, ethoxy, acetoxy, acetamido, cyano, nitro, nitroso, methylmercapto, ethylmercapto, carboxyl, sulfonate, or sulfinate groups; and wherein any cycloalkyl or aryl group is additionally optionally substituted with one or more methyl or ethyl; wherein none of R 1 , R 2 , and R 3 are identical to each other, and no two of R 1 , R 2 , and R 3 are linked together to form a cycloalkyl or aryl ring.