| 摘要 |
<p>The present invention relates to compounds of formula (I) and the pharmaceutically acceptable salts thereof, wherein the dashed line represents an optional covalent bond; X is O, NH, S or a direct link; R3 is hydroxy when the dashed line does not represent a covalent bond and R3 is absent when the dashed line represents a covalent bond; R4 is (a), when X is O, a group of formula (i), (b), when X is O, NH or S, optionally substituted hydroxyphenyl, (c) an optionally substituted 4- to 7-membered heterocyclic ring, or (d), when X is NH, a group of formula (ii). The compounds are useful for the treatment of disease associated with the altered tone or motility of smooth muscle.</p> |
