| 摘要 |
A compound of the formula (I): <IMAGE> (I) wherein: X is O, S or H; Y is -CH2-CH-, -CH=CH- or -C=C-; n is 1 to 7; R1 is C1-4 alkyl; R3 is hydroxy or protected hydroxy; R4 is C1-9 alkyl, C3-8 cycloalkyl or C3-8 cycloalkyl-C1-6 alkyl; or R2 and R4 taken with the carbon atom to which they are joined represent a C5-8 cycloalkyl group; and R5 is hydrogen or C1-6 alkyl; and salts thereof has useful pharmaceutical activity including bronchodilator activity. |
