Patent ID: 7265247

Claim:
A compound of the formula (I): in which R 1a and R 1b are independently a hydrogen atom or a primary or secondary alkyl group having from one to eight carbon atoms; R 2a and R 2b are independently a hydrogen atom or a primary, secondary, or tertiary alkyl group having from one to eight carbon atoms; and R 3 is a hydrogen atom, a halogen atom, or a primary, secondary, or tertiary alkyl group having from one to eight carbon atoms; wherein, when R 3 is a hydrogen atom, at least two of R 1a , R 1b , R 2a , and R 2b are primary, secondary, or tertiary alkyl groups having from one to eight carbon atoms and the others are a hydrogen atom, and wherein, when R 3 is a primary alkyl group having from one to eight carbon atoms, at least one of R 1a , R 1b , R 2a , and R 2b is a primary, secondary, or tertiary alkyl group having from one to eight carbon atoms and the others are a hydrogen atom, and wherein when at least two of R 2a , R 2b , and R 3 are tertiary alkyl groups, the tertiary alkyl groups are non-adjacent.