| 主权项 |
1. A compound having the structure of formula (I): In which: X is O or H2 R1 is a hydrogen atom, a straight-chain C1-C5 alkyl group, a branched C1-C5 alkyl group, a C3-C5 cycloalkyl group or a halogen atom; R2 is a hydrogen atom, a straight-chain C1-C5 alkyl group, a branched C1-C5 alkyl group, a C3-C5 cycloalkyl group or a halogen atom; or R1 and R2 together are a methylene group, R3 is a hydrogen atom, a straight-chain C1-C5 alkyl group, a branched C1-C5 alkyl group, a C3-C5 cycloalkyl group or a halogen atom; R4 is a hydrogen atom, a straight-chain C1-C5 alkyl group, a branched C1-C5 alkyl group, a C3-C5 cycloalkyl group or a halogen atom; or R3 and R4 together are an additional bond or a methylene group, R5 an N imidazolyl group that is optionally substituted by one or more alkyl groups R6 stands for a free, etherified or esterified hydroxyl group, R7 stands for a radical of formula CnFmHo whereby n is 2, 3, 4, 5 or 6 with m≧1 and m+o=2n+1 or 2n−1 or 2n−3 |
