Methoxymethylene

The 6-methoxymethylene penicillanic acid [93040-42-7] (31, R = CH OCH (2)-isomer, R" = R " = 3) designed to mimic the amino acrylate species found usiag clavulanic acid and sulbactam. Upon the reaction of this compound with the enzyme, the potential exists for further Michael addition to inactivate the enzyme. The compound is indeed a -lactamase inhibitor but no synergy data have been reported. The related imine stmcture... 

Reaction of the cisoid methoxymethylene ketone (36) with decomposing sodium chlorodifluoroacetate yields two epimeric adducts in 42 and 28 % yield, respectively, to which structure (37) has been assigned on the basis of NMR... 

Methoxymethylene, 231 Ethoxymethylene, 231 Dimethoxymethylene, 232 1 -Methoxyethylidene, 232 1 -Ethoxyethylidine, 232 Methylidene, 233 Phthalide, 233... 

Acetonide Derivative 11. Benzylidene Acetal 13. p-Methoxybenzylidene Acetal 18. Methoxymethylene Acetal 20. Dimethoxymethylenedioxy Derivative... 

Aldehydes can be prepared by the Wittig reaction using (methoxymethylene)-triphenylphosphorane as the Wittig reagent and then hydrolyzing the product with acid. For example,... 

The Wittig reaction can be applied to various functionalized ylides.246 Methoxymethylene and phenoxymethylene ylides lead to vinyl ethers, which can be hydrolyzed to aldehydes.247... 

In 1986, Kesselmayer and Sheridan reported the matrix isolation and IR spectrum of chloro-methoxymethylene. They were able to show that two isomeric forms were present, trans (12) and cis (13). This is in line with Schaefer s " finding that hydroxymethylene should exist in cis- and frons-forms. While Kesselmayer and Sheridan were able to assign several of the bands in the matrix mixture to the cis- and trans-forms, they were unable to assign the majority of the bands in the IR spectrum they obtained to the specific isomer. In order to further confirm their isolation of these alkoxy carbenes, as well as to help in the interpretation of the observed IR spectrum, we undertook the calculation of the IR spectra of 12 and 13. ... 

Reacting this with ethyl orthoformate gives a methoxymethylene derivative... 

Reactions of Cjq with metal carbene complexes also yield the [6,6] methano-fullerenes [392]. These adducts are probably not formed via a carbene addition, but via a formal [2-1-2] cycloaddition under formation of a metalla cyclobutane intermediate. The Fischer carbene complex [mefhyl(methoxymethylene)]pentacarbonyl chromium can be utilized to prepare l,2-mefhyl(methoxymethano)-fullerene in 20% yield [392]. A tungsten carbene complex was primarily used to initiate the formation of a polyacetylene polymer, but it was discovered that addition of to the complex-polymer-mixture improves the polymerization and dramatically increases the catalytic activity of the carbene complex [393]. can be integrated into the polymer via carbene addition. 

Flash vacuum pyrolysis (FVP) of the tetrahydro-l,3-oxazine derivative 171, derived from the condensation of spiro-oxazine 170 and methoxymethylene-substituted Meldmm acid, resulted in formation of pyrrolo[l,2-r ][l,3]oxazine 172, which in (CD3)2CO at —20°C proved to be a 47 53 mixture of the keto (A) and enol (B) tautomers (Scheme 28) <2002J(P1)548>. 

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