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2-Methoxyethoxymethyl chloride, is used as selectively cleaved under aprotic conditions in the presence of a wide range of OH-protected reagents. It is used as an OH-protecting reagent. An examples of the target molecule MEM Chloride is the side chain of roxithromycin. It is also used in the protection of the OH groups in serine and threonine during peptide synthesis. Some of the other applications include have the ability to coordinate to metals, which is thought to accelerate the cleavage by Lewis acids. The chelating ability of the MEM ether also makes it useful as a stereodirecting group in organometallic reactions, first noted in the stereo controlled addition of ?-methoxyvinyllithium to a carbonyl in the synthesis of taxusin.
JH Rigby.; JAZ Wilson. Removal of methoxyethoxymethyl ethers with trimethylsilyl chloride-sodium iodide. Tetrahedron letters. 198425(14) , 1429-1432.
RS Gross.; DS Watt. A Lewis acid-catalyzed procedure for the conversion of 2-methoxyethoxymethyl ethers to carboxylic esters. Synthetic Communications. 198717(15) , 1749-1760.
Reagent for the protection of OH groups, in the presence of a base, e.g. NaH in THF or N-Ethyldiisopropylamine, A11801. The MEM-group is more readily and cleanly introduced than methoxymethyl (MOM) and is stable to a wide range of conditions. The MEM group is selectively cleaved by mild Lewis acids, e.g. ZnBr2 or TiCl4: Tetrahedron Lett., 809, 4701, 4705 (1976); 24, 3969 (1983), PPTS: Synth. Commun., 13, 1021 (1983), in situ generated TMS iodide: Tetrahedron Lett., 25, 1429 (1984), or CeCl3: Org. Lett., 3, 1149 (2001).
For use in the protection of the OH groups in serine and threonine during peptide synthesis, see: Int. J. Pept. Prot. Res., 25, 544 (1985). See also Appendix 6.
MEM ethers have the ability to coordinate to metals, which is thought to accelerate the cleavage by Lewis acids. The chelating ability of the MEM ether also makes it useful as a stereodirecting group in organometallic reactions, first noted in the stereocontrolled addition of ɑ-methoxyvinyllithium to a carbonyl in the synthesis of taxusin: J. Am. Chem. Soc., 110, 6558 (1988), and subsequently in the addition of MeLi to an ɑß-unsaturated sulfone: J. Am. Chem. Soc., 113, 3085 (1991); see 2,2,2-Trifluoroethanol, A10788, for another example.
For cleavage by PPTS, see: Synth. Commun., 1021 (1983). For cleavage by TMS chloride/ NaI or, less effectively, by preformed TMS iodide, see: Tetrahedron Lett., 25, 1429 (1984).
Dichiarazioni di rischio (UE): H226-H315-H319-H350-H335
Flammable liquid and vapour. Causes skin irritation. Causes serious eye irritation. May cause cancer. May cause respiratory irritation.
Dichiarazioni precauzionali: P260-P201-P280a-P304+P340-P405-P501a
Do not breathe dust/fume/gas/mist/vapours/spray. Obtain special instructions before use. Wear protective gloves and eye/face protection. IF INHALED: Remove to fresh air and keep at rest in a position comfortable for breathing. Store locked up. Dispose of contents/container in accordance with local/regional/national/international regulations.