| abstract |
Claim 1: A compound of formula (1), wherein R¹ and R² are, independently of each other, H, C₁₋₈ alkyl, C₁₋₈ haloalkyl, C₁₋₈carbonyl alkyl or C₁₋₈carbonyl alkoxy; R³ is hydrogen, C₁₋₄ alkoxy or halogen; and R⁴ and R⁵i) are, independently of each other, hydrogen, hydroxyl or halogen; or ii) they form a carboxyl or thiocarboxyl group, except when R³ is fluorine. |