Methylthiomethyl ether
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2007-11-25T01:13:21Z
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In [[organic chemistry]] a '''methylthiomethyl (MTM) [[ether]]''' is a [[protective group]] for [[Hydroxide|hydroxyl groups]]. Hydroxyl groups are present in many chemical compounds and they must be protected during [[oxidation]], [[acylation]], [[halogenation]], [[Dehydration reaction|dehydration]] and other reactions to which they are susceptible.
Many kinds of [[protective group]]s for hydroxyl groups have been developed and used in organic chemistry, but the number of protective groups for tertiary hydroxyl groups, which are susceptible to acid-catalyzed [[dehydration]], is still small because of their poor reactiveness. But they can be easily protected with MTM [[ether]]s and recovered in good yield.
To introduce an MTM [[ether]] to a hydroxyl group, two methods are mainly used. One is a typical [[Williamson ether synthesis]] using an MTM [[halide]] as an MTM resource and [[sodium hydride]] (NaH) as a base. The other is a special method, in which [[dimethyl sulfoxide]] (DMSO) and [[acetic anhydride]] (Ac<sub>2</sub>O) are used. In this case, the reaction proceeds with [[Pummerer rearrangement]]:
MTM [[ether]]s have another advantage. They are removed by neutral (but toxic) [[mercuric chloride]], to which most other ethers are stable. As a result, the selective deprotection of polyfunctional molecules becomes possible using MTM [[ether]]s as the [[protective group]]s for their hydroxyl groups.
[[Category:Thioethers]]
[[Category:Protecting groups]]