摘要 |
<p>Compounds of formula (I): <IMAGE> (I) [wherein X represents a hydrogen atom or a 2-methylbutyryl group, Y represents a hydrogen atom or a methyl group and R1 and R2 are the same or different and each represents an oxygen atom or a group of formula =N-OR3 (wherein R3 represents a hydrogen atom or an alkyl group)], the free hydroxy-carboxylic acids corresponding thereto and salts and esters of said acids may be prepared by oxidizing and, if necessary, oximating a corresponding ML-236A, ML-236B, MB-530A or MB-530B compound, and these compounds have valuable antihypercholesteraemic activity.</p> |