1.2- dimethoxy-methane

All solvents used for general applications were of reagent grade. For special purposes, purification of solvents was effected using standard procedures. All other reagents were used as supplied commercially except as noted. A solution of chloromethyl methyl ether (6 mmole/mL) in methyl acetate was prepared by adding acetyl chloride (141.2 g, 1.96 mol) to a mixture of dimethoxy methane (180 mL, 2.02 mol) and anhydrous methanol (5.0 mL, 0.12 mol).20 The solution was diluted with 300 mL of 1,1,2,2-tetrachloroethane and used as a stock solution for the chloromethylation experiments. 

Formaldehyde dimethyl acetal (dimethoxy methane, methylal, formal) [109-87-5] M 76.1,... 

Formaldehyde dimethyl acetal (dimethoxy methane, methylal, formal) [109-87-5] M 76.1, m -108 , b 41-42 /736mm, 41-43 /atm, 42-46 /atm, d ° 0.8608, n2D° 1.35335. It is a volatile flammable liquid which is soluble in three parts of H2O. It is readily hydrolysed by acids. Purify by drying... 

Experimental Procedure Aerosol Fluorination of Dimethoxy methane [29]... 

Zinc enolates can be prepared in solvents of greatly different polarity, including THF, DME, Et20, 1,4-dioxane, benzene, toluene, dimethoxy-methane, DMF, B(OMe)3, DMSO, and mixtures thereof, just to mention the most frequently used ones.1-3 Reformatsky reactions in the absence of a solvent have also been described.7 The reagent is dimeric in the crystal state and in solution except for the most polar media.5,8... 

Its major success seems, or at least seemed, to be its ability to rationalise the shortening of the C(l)—0(5) bond, and lengthening of the C(l)—X bond in the equatorial, but not the axial case. Thus Jeffrey et al. (1978) examined the crystal structures of a wide range of carbohydrates and compared them with the results of ab initio calculations on dimethoxy-methane (RHF/4-31G basis set). They found excellent agreement between experiment and theory, in particular finding that in a-glycosides both the... 

Sometimes the effects of solvent may not be very great. 3-t-Butyl-6-dimethylaminopyridazine reacted with methyl iodide in acetonitrile to give a 63 37 ratio of 1- and 2-methiodides. The results in hexane, benzene, carbon tetrachloride, and acetone were similar, and only in ethers [dimethoxy-methane, 79 21 tetrahydrofuran (THF), 84 16] did the product ratios vary to any extent, perhaps because the methylating agent in ethers is an oxonium salt (73ACS383). 

A mild procedure for the appendage of MOM groups to acid-sensitive substrates is illustrated by the protection of the allylic alcohol in Avermectin derivative 259.1 using [(methoxymethyl)thio]-2-pyridine (259 2) sitver(I) Inflate and sodium acetate in THF at room temperature [Scheme 4.259],479 Primary secondary and tertiary alcohols and phenols are methoxymethylated in good yield though phenols are slower to react. Reagent 259.2 (bp 66 °C/0.088 kPa) is easily prepared in 75% yield by the reaction of pyridine-2-thiol with dimethoxy-methane activated by trifluoroborane etherate. 

Methoxymethyl methyl sulfate (3). To a stirred solution o( dimethoxy methane 1 (6 08 g, 80 mrrwl) in CHjCIa at 60°C was added (reshly distilled SO3 2 (6 40 g, 80 mmol) to give a solution of 3... 

Fig. 26.—Interactions of Lone-pair Orbitals on Oxygen Atoms with (a) Antibonding Orbitals of CHj Group and (b) Antibonding Orbital of Adjacent C - O Bond, for (ap, ap) and (ap, og) Conformations of Dimethoxy methane. [For the sake of simplicity, only one of two perpendicular antibonding orbitals of the CH2 group and the antibonding orbital of one C - O bond are shown.]...

Dialkylamino-dimethoxy-methane allgemeine Arheitsvorschrift199 Zu 204 ml einer 30%igen Natriummetha-nolat-L6sung(Fluka)gibtmanallmahlich unter Rtihren bei 0-20° 1 mol Dialkylamino-methoxy-acetonitril... 

Bis-[alkylthio]-dialkylamlno-mcthanc allgcmeine Arbeitsvorschrift483 Zu 0,5 mol Dialkylamino-dimethoxy-methan gibt man 1 mol Alkanthiol, erhitzt an einer Fullkorperkolonne zum Sieden und nimmt das Methanol liber Kopf ab. Die Bis-[alkylthio]-dialkylamino-methane werden i. Vak. destilliert. Bei der Umsetzung mit niedrig siedenden Alkanthiolen erhitzt man vor der fraktionierenden Destination 4 Stdn. unter Riick-fluB. 

Protection of ethyl L-lactate with a MOM group (377) can be effected in high yield with either chloromethyl methyl ether in the presence of Hunig s base [100,119] or with dimethoxy-methane and phosphorus pentoxide [120]. 

PC = propylene carbonate DN = 1,3-dioxolane EC = ethylene carbonate 3-MeS-3 = methyl sulfolane DME = dimethoxy ethane THE = tetrahydrofuran S = sulfolane DMSO = dimethyl sulfoxide, DEE = diethyl ether, 2-Me-F = 2 methyl furan 2-MeDN = 2-methyl 1,3-dioxolane MA = methylacetate DMM = dimethoxy methane 2-MeOTHF = 2 methoxytetrahydrofuran BL = y-butyrolactone NM = nitromethane AN = acetonitrile MF = methyl formate DEC = diethyl carbonate DMC = dimethyl carbonate. 

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