| 摘要 |
<p>Title cpds. of formula (I): (where R1-R5 are H or 1-40C hydrocarbon residues which may be linked with each other to form 5- or 7-membered rings opt. contg. O as a heteroatom, and R4 can additionally be 1-8C alkoxy), are of use of inters., esp. for plant-protection agents and perfumes. They are prepd. by treating a cpd. of formula (II): with an acidic agent (suitably a nonoxidising inorganic acid, an organic acid, an acidic salt, an acidic ion-exchanger or a Lewis acid) at -100 to +150 degrees C (pref. -20 to +60 degrees C).</p> |
