Alkoxymethyl

The mechanism of the alkylation reaction is similar to curing. The methylo1 group becomes protonated and dissociates to form a carbonium ion intermediate which may react with alcohol to produce an alkoxymethyl group or with water to revert to the starting material. The amount of water in the reaction mixture should be kept to a minimum since the relative amounts of alcohol and water determine the final equiHbrium. 

Imidazole, 4-acetyl-5-methyl-2-phenyl-synthesis, 5, 475 Imidazole, 1-acyl-reactions, 5, 452 rearrangement, 5, 379 Imidazole, 2-acyl-synthesis, 5, 392, 402, 408 Imidazole, 4-acyl-synthesis, 5, 468 Imidazole, C-acyl-UV spectra, 5, 356 Imidazole, N-acyl-hydrolysis rate constant, 5, 350 reactions, 5, 451-453 synthesis, 5, 54, 390-393 Imidazole, alkenyl-oxidation, 5, 437 polymerization, 5, 437 Imidazole, 1-alkoxycarbonyl-decarboxylation, 5, 453 Imidazole, 2-alkoxy-l-methyl-reactions, 5, 102 thermal rearrangement, 5, 443 Imidazole, 4-alkoxymethyl-synthesis, 5, 480 Imidazole, alkyl-oxidation, 5, 430 synthesis, 5, 484 UV spectra, 5, 355 Imidazole, 1-alkyl-alkylation, 5, 73 bromination, 5, 398, 399 HNMR, 5, 353 synthesis, 5, 383 thermal rearrangement, 5, 363 Imidazole, 2-alkyl-reactions, 5, 88 synthesis, 5, 469... 

Pyrylium salts, 3-acetyl-2,4,6-trimethyl-crystallography, 3, 625 Pyrylium salts, 3-alkoxymethyl-synthesis, 3, 865 Pyrylium salts, alkyl-deprotonation, 2, 51 reactions, 2, 50 Pyrylium salts, 2-amino-reactions, 2, 55 Pyrylium salts, 4-amino-deprotonation, 2, 55... 

S-Benzyl and substituted S-benzyl derivatives, readily cleaved with sodium/ammonia, are the most frequently used thioethers. n-Alkyl thioethers are difficult to cleave and have not been used as protective groups. Alkoxymethyl or alkylthio-... 

Treatment of a nylon with formaldehyde leads to the formation of A-methylol groups but the polymers are unstable. If, however, the nylon is dissolved in the solvent such as 90% formic acid and then treated with formaldehyde and an alcohol in the presence of an acidic catalyst such as phosphoric acid a process of alkoxymethylation occurs Figure 18.19). 

A study of the reductive cleavage of a series of alkoxymethyl ethers using the glucose backbone shows that, depending on the reagent, excellent selectivity can be obtained for deprotection vs. methyl ether formation for most of the common protective groups. ... 

Functionalized 5-alkoxymethyl- and 5-phenoxymethyl-2(5//)-furanones 44-46 were obtained starting from 3-alkoxy- and 3-phenoxy-2-hydroxy ketones 40 (98T1801). Condensation of the hydroxy ketones 40 with a slight excess of diethyl malonate 41 (Z = COOMe R = Me), ethyl cyanoacetate 42 (Z = CN R = Me),... 

An extensive survey has been carried out by McKervey and coworkers [7], who prepared the carbo-alkoxymethyl ethers of p-tert-h x y calix[4]arene, p-/< r/-butyl calix[6]arene, p-tert-bu y calix[8]arene, ca-lix[4]arene, calix[6Jarene, and calix[8]arene, and measured their abilities to extract cations from the aqueous phase into the nonaqueous phase. They concluded the following general aspects for the phase-transfer experiments (1) the calix[4]arene compounds show the greatest selectivity for Na (2) phase-transfer of Li is inefficient with all of the compounds (3) the calix[6]arene compounds show less affinity for Na than for K, with plateau selectivity for Rb" and Cs (4) the calix[8]ar-ene compounds are the least efficient of the cyclic oligomers, showing low levels of transport and low discrimination for all five cations (5) the calix[6]arene... 

A key transformation in Corey s prostaglandin synthesis is a Diels-Alder reaction between a 5-(alkoxymethyl)-l,3-cyclopenta-diene and a ketene equivalent such as 2-chloroacrylonitrile (16). As we have already witnessed in Scheme 3, it is possible to bring about a smooth [4+2] cycloaddition reaction between 5-substituted cyclopentadiene 15 and 2-chloroacrylonitrile (16) to give racemic 14 as a mixture of epimeric chloronitriles. Under these conditions, the diastereomeric chloronitriles are both produced in racemic form because one enantiotopic face of dienophile 16 will participate in a Diels-Alder reaction with the same facility as the other enantiotopic face. In subsequent work, Corey s group demonstrated that racemic hydroxy acid 11, derived in three steps from racemic 14 (see Scheme 3), could be resolved in a classical fashion with (+)-ephe-... 

Examples of the synthesis of 4,5-dialkoxy-, 4,5-di(alkoxymethyl)- and 4,5-dialkyl-substituted phthalonitriles are shown below. 

There have heen many studies on the polymerizability of a-substituted acrylic monomers.3jU35 33S It is established that the ceiling temperature for a-alkoxyacrylates decreases with the size of the alkoxy group. 35 However, it is of interest that polymerizations of a-(alkoxymethyl)acrylates (67)3 15 and a-(acyloxymethyl)acrylates (68)and captodative substituted monomers (69, 70) 39 appear to have much higher ceiling temperatures than the corresponding a-alkylacrylates methyl ethacrylate, MEA). For example, methyl a-... 

The mechanism of the nucleophilic substitution of a-halogenosulphoxides depends on structural factors and the nature of a nucleophile and may occur according to two competitive mechanisms a direct 8 2 substitution and an elimination-addition process . Thus, chloromethyl and bromomethyl sulphoxides react with alkoxide and mercaptide anions via an 8, 2 mechanism to give the corresponding a-alkoxy and a-alkylthiomethyl sulphoxides 502, respectively (equation 305). Optically active a-alkoxymethyl and a-alkylthiomethyl sulphoxides can also be obtained in this way - . 

Methyl-diethyl-alkoxymethyl ammonium methyl sulfate has high foam extinguishing properties [563],... 

Similar chelation effects are present in a-alkoxymethyl derivatives. Magnesium enolates give predominantly the Z-enolate as a result of this chelation. The corresponding trimethylsilyl ketene acetals give E,Z mixtures.248... 

Entry 11 involves generation and cyclization of an alkoxymethyl radical from a selenide. The cyclization mode is the anticipated 5-exo with a cis ring juncture. This is a case in which the electronic characteristics of the radical are not particularly favorable (ERG oxygen in the radical), but cyclization nevertheless proceeds readily. The reaction in Entry 12 was used to prepare a precursor of epibatidine. Entry 13 shows a 6-endo cyclization that is favored by steric factors. The 6-endo cyclization is also favored with a tetrahydropyranyloxy substituent in place of the ester, indicating that the electronic effect is not important. Entries 14 to 16 involve acyl radicals generated from selenides. The preferred 6-endo cyclization in Entry 15 is thought to be due to the preference for the less-substituted end of the double bond. Entry 17 is an example of a 5-exo-dig cyclization. 

The spectroscopically characterized iron methylene complex 63 is formed in a closely related reaction of an alkoxymethyl compound (92) ... 

We have delineated viable coordinated ligand reactions and their attendant intermediates for the stoichiometric conversion of CO ligands selectively to the C2 organics ethane, ethylene, methyl (or ethyl) acetate, and acetaldehyde. We now outline results from three lines of research (1) T -Alkoxymethyl iron complexes CpFe(C0)2CH20R (2) are available by reducing coordinated CO on CpFe(C0)3+ (1) [Cp = r -CsHs]. Compounds 2 then form t -alkoxyacetyl complexes via migratory-insertion (i,e. CO... 

We have demonstrated that NaBH3CN in alcohol reduces a CO ligand on CpFe(CO)3+ and generates an alkoxymethyl iron complex. Versatile alkoxyacetyl complexes CpFe(C0)L(C0CH20R)... 

Reductive nucleophilic cleavage of the l-alkoxymethyl-6,8-dioxabicyclo[3.2.11-octanes 44 catalysed by TiCl4 leads to the formation of the oxepane derivatives 45 (eg. R = Me) in good yield <00T1065>. 

Nucleophilic addition of furan to nitrone occurs upon treatment with trimethyl-silyl triflate (TMSOTf) (586, 587). Catalyzed TMSOTf stereoselective addition of 2-[(trimethylsilyl)oxy]furan to chiral nitrones was carried out in a short synthesis of [IS (la, 2[), 7f>, 8a, 8aa)]-l,2-di(t-butyldiphenylsilyloxy)-indolizidine-7,8-diol (588). Addition to N -gulosyl-C-alkoxymethyl nitrones led to the synthesis of the core intermediate of polyoxin C (218). 

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