2-Methoxyethoxymethyl chloride

2-Methoxyethoxymethyl chloride is an organic compound with formula CH₃OCH₂CH₂OCH₂Cl. A colorless liquid, it is classified as a chloroalkyl ether. It is used as an alkylating agent. In organic synthesis, it is used for introducing the methoxyethoxy ether (MEM) protecting group.^[2] MEM protecting groups are generally preferred to methoxymethyl (MOM) protecting groups, both in terms of formation and removal.

2-Methoxyethoxymethyl chloride

Identifiers
CAS Number	3970-21-6
3D model (JSmol)	Interactive image
ChemSpider	69995
ECHA InfoCard	100.021.446
EC Number	223-589-8
PubChem CID	77590
UNII	A5RRM67QUG
CompTox Dashboard (EPA)	DTXSID8063250
InChI InChI=1S/C4H9ClO2/c1-6-2-3-7-4-5/h2-4H2,1H3 Key: BIAAQBNMRITRDV-UHFFFAOYSA-N
SMILES COCCOCCl
Properties
Chemical formula	C4H9ClO2
Molar mass	124.56 g·mol−1
Appearance	colorless liquid
Density	1.094 g cm−3
Boiling point	50–52 °C (122–126 °F; 323–325 K) 13 mm Hg
Hazards
GHS labelling:[1]
Pictograms
Signal word	Danger
Hazard statements	H226, H302, H315, H319, H335
Precautionary statements	P203, P210, P233, P240, P241, P242, P243, P261, P264, P264+P265, P270, P271, P280, P301+P317, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P318, P319, P321, P330, P332+P317, P337+P317, P362+P364, P370+P378, P403+P233, P403+P235, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Typically, the alcohol to be protected is deprotonated with a non-nucleophilic base such as N,N-diisopropylethylamine (DIPEA, Hunig's base) in dichloromethane followed by addition of 2-methoxyethoxymethyl chloride.^{[3] [4]}

The MEM protecting group can be cleaved (deprotection) with a range of Lewis and Bronsted acids.^[5]

Safety

The closely related chloromethyl methyl ether is a known human carcinogen.^[6]

References

1. "2-Methoxyethoxymethyl chloride". pubchem.ncbi.nlm.nih.gov.
2. Wuts, Peter G. M. (2001). "2-Methoxyethoxymethyl Chloride". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rm100. ISBN 0471936235.
3. Corey, E. J.; Gras, Jean-Louis; Ulrich, Peter (1976-03-01). "A new general method for protection of the hydroxyl function". Tetrahedron Letters. 17 (11): 809–812. doi:10.1016/S0040-4039(00)92890-9.
4. Lee, Hong Myung; Nieto-Oberhuber, Cristina; Shair, Matthew D. (2008-12-17). "Enantioselective Synthesis of (+)-Cortistatin A, a Potent and Selective Inhibitor of Endothelial Cell Proliferation". Journal of the American Chemical Society. 130 (50): 16864–16866. doi:10.1021/ja8071918. ISSN 0002-7863. PMID 19053422. S2CID 207132632.
5. Amano, Seiji; Takemura, Noriaki; Ohtsuka, Masami; Ogawa, Seiichiro; Chida, Noritaka (1999-03-26). "Total synthesis of paniculide A from d-glucose". Tetrahedron. 55 (13): 3855–3870. doi:10.1016/S0040-4020(99)00096-4.
6. bis(Chloromethyl) Ether and Technical-Grade Chloromethyl Methyl Ether CAS Nos. 542-88-1 and 107-30-2 Report on carcinogens, eleventh edition