Tetramethoxymethane is a chemical compound which is formally formed by complete methylation of the hypothetical orthocarbonic acid .
Preparation The obvious synthetic route from the tetrahalomethanes does not yield the desired product, instead giving orthoformates and a halohydrin byproduct.R. H. De Wolfe, Carboxylic ortho acid derivatives: preparation and synthetic applications, Organic Chemistry, Vol. 14, Academic Press, Inc. New York – London, 1970, . The original preparation of the tetramethoxymethane was therefore based on chloropicrin:
Because of the extreme toxicity of chloropicrin, other tetrasubstituted reactive methane derivatives were investigated as starting material for tetramethoxymethane. For example, trichloromethanesulfenyl chloride (also used as a chemical warfare agent and easily accessible from carbon disulfide and chlorine) was used:H. Tieckelmann, H. W. Post, The preparation of methyl, ethyl, propyl, and butyl orthocarbonates, J. Org. Chem., 13 (2), 265-267 (1948), .US-Patent US 4,059,656, Processes for neutralizing 2,3-dibromopropanol phosphoric acid esters contained in tris(2,3-dibromo-1-propyl) phosphate, Erfinder: M. Demarcq, Anmelder: Produits Chimiques Ugine Kuhlmann, erteilt am 22. November 1974.
A less problematic synthesis is based on trichloroacetonitrile:US-Patent US 3,876,708, Orthocarbonic acid esters, Erfinder: R. Speh, W. Kantlehner, Anmelder: Akzo B.V., erteilt am 8. April 1975.US-Patent US 6,825,385 B2, Process for the preparation of orthocarbonates, Erfinder: G. Fries, J. Kirchhoff, Anmelder: Degussa AG, erteilt am 30. November 2004.
Thallium methoxide reacts with carbon disulfide to give tetramethoxymethane and thallium sulfide; likewise dimethyl dibutylstannate gives tetramethoxymethane and dibutyltin sulfide. Further preparative methods are described in the literature.W. Kantlehner et al., Die präparative Chemie der O- und N-funktionellen Orthokohlensäure-Derivate, Synthesis; 1977(2): 73-90, .
Synthesis from chloropicrin only yields about 50% product. Syntheses from trichloromethanesulfenyl chloride or trichloroacetonitrile or the thallium-sulfide route yield about 70-80% product, but the tin-sulfide synthesis has a 95% yield.
Properties Tetramethoxymethane is a clear, colorless, aromatic-smelling, low-viscosity liquid which is stable against peroxide formation.
Use In addition to its use as a solvent, tetramethoxymethane is also used as a fuel in polymer fuel cells,US-Patent US 6,864,001, Tetramethyl orthocarbonate fuel cells and systems and methods related thereto, Erfinder: J. Zhang, K. Colbow, Anmelder: Ballard Power Systems Inc., erteilt am 8. März 2005. as an alkylating agent at elevated temperatures (180-200 °C),M. Selva et al., Esters and Orthoesters as Alkylating Agents at High Temperature. Applications to Continuous-flow Processes, J. Chem. Soc., Perkin Trans. 2, 519 (1992), . as a transesterification reagent (but showing less reactivity than trimethoxymethane), and as a reagent for the synthesis of 2-aminobenzoxazoles, which are used as molecular building blocks in pharmaceutical active ingredients used in neuroleptics, sedatives, antiemetics, muscle relaxants, fungicides and others.C. L. Cioffi et al., Synthesis of 2-Aminobenzoxazoles Using Tetramethyl Orthocarbonate or 1,1-Dichloro-diphenoxymethane, J. Org. Chem., 75 (2), 7942-7945 (2010), .
Depending on the substituents, the one pot reaction proceeds in "modest to excellent" yields.
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