abstract |
Compounds of the formula wherein R is a hydrogen atom or a lower alkyl group, R1 and R2 are each selected from a hydrogen atom or a lower alkyl group, R3, R4 and R6 are each selected from a hydrogen or halogen atom or a lower alkyl group, R5 A hydrogen atom, a hydroxy group, a halogen atom, a lower alkyl group, a lower alkoxy group, a lower mono- or dialkylamino group, NH 2 or NR 11 COR 12, R 7, R 8, R 9 and R 10 are each hydrogen atom, hydroxy group, lower alkyl group, lower one Alkoxy group, a lower mono- or di-alkylamino group, NH 2 or NR 11 COR 12, R 11 is a hydrogen atom or a lower alkyl group, R 12 is a lower alkyl group, provided that when R is a hydrogen atom, at least one of substituents R 1 to R 10 no hydrogen atom or a salt thereof is useful as an antioxidant, and e.g. was both in the medical and non-medical fields, and that when R in the formula (IA) is a hydrogen atom, a methyl or neopentyl group, at least one of the substituents R 1 to R 10 is not a hydrogen atom. Many of the compounds of formulas (IA) and (IB) are novel and various methods for their preparation are described. formula |