Derivatization for Enhanced Isolation: Permethyl Ethers and Acetates

In a number of cases, isolation is accomplished after derivatization, because of instability of the parent compounds, into permethyl ethers or acetates followed by column chromatography. The isolation is the main subject of this sentence. The verb 'is accomplished' indicates the action, and the phrase 'after derivatization' serves as the object, detailing the method used for isolation.