Methyl ethers, preparation

To a solution of 5 mmol of 1,3-diphcnyl 3-[(S )-2-mcthoxymethyl-l-pyrrolidinyl]-2-propenyl[lithium in 10 mL of tort-butyl methyl ether (prepared according to Section D. 1.1.1.2.2.3.) at 0°C. 6.25 mmol of the aldehyde (and eventually 6.25 mmol of lithium halogenide in 27 mL of leri-butyl methyl ether) are added dropwise. Stirring is continued for 2 h and 0.39 g (5.0 mmol) of acetyl chloride are added. After 2 h stirring at r.t., 10 mL of the solvent, 50 mL of diethyl ether and 10 mL of 2 N aq hydrochloric acid are added and stirring is continued for 2 h at 20 C. The organic layer is extracted with three 20 mL-portions of water and the aqueous solutions are reextracted with diethyl ether. The combined aqueous solutions are dried over Na,S04, concentrated in vacuum and the residue distilled to yield a mixture of xyn- and on/i-ketones >90% ee, determined by H-NMR with Pr(hfc)3. 

The infrared spectra of l,4-anhydro-3,5-0-methylene- and -2-0-methyl-DL-xylitol have been studied.60 The 2-methyl ether was obtained by converting l,4-anhydro-3,5-0-methylene-DL-xylitol into its monomethyl ether, and then hydrolyzing off the methylene group. A methyl ether prepared from the known l,4-anhydro-3,5-0-isopro-pylidene-2-O-methyl-DL-xylitol proved to be identical with this compound, thus establishing at the same time that the methylene group in the known acetal is attached to 0-3 and 0-5 of 1,4-anhydro-DL-xylitol. The methylene group, having a 1,3-dioxolane structure, was characterized by an absorption band at about 2800 cm 1. 

Isocodeine methyl ether, prepared from the methyl ether methiodide [411] or by methylating isocodeine-N-oxide and reducing the product [265], cannot be isomerized to thebainone methyl enolate by heating with sodium ethoxide [265]. On degradation it yields y-codeimethine methyl ether [411]. 

In a similar way [lxxxii, R = H] was reduced to [xcvxn], which converted by Wolf-Kishner reduction to [xoix],. which in turn was reduced with lithium aluminium hydride and methylated to give dZ-/3-dihydrodesoxycodoine-B methyl ether [c]. The product was compared, by means of the infra-red absorption spectra, with dihydro-desoxycodeine-B methyl ether prepared from dihydrothebainol-B [oi] and with /3-dihydrodesoxycodeine-B methyl ether prepared from /3-dihydrothobainol-B, which is the C-14 epimor of [oi]. The spootra of... 

K. Bock, C. Pedersen, and P. Rasmussen, Reactions of acylated pentoses and acylated methyl pentosides with dibromomethyl methyl ether. Preparation of bromo-deoxy-pentoses, J. Chem. Soc., Perkin I, (1973) 1456-1461. 

G- C] Codeine methyl ether (prepared from generally labelled morphine obtained biosynthetically by feeding to P. somniferum) (fed for 24 h)... 

This product ie a viscous liquid, someAvhat heavier than AA ater, AA hich distills at 97--99°C at approximately 13 mm pressure. Other polyhalo-methyl ethers prepar-ed by reactions of formaldehyde Avith polyhydroxyl compounds and hydrogen halides do not appear to have been reported. 

A solution of methylmagnesium bromide in 150 ml of diethyl ether, prepared from 0.5 mol of methyl bromide (see Chapter II, Exp. 5) was subsequently added in 20 min with cooling at about 20°C. After the addition the mixture was warmed for 2 h under reflux (the thermometer and gas outlet were replaced with a reflux condenser), a black slurry being formed on the bottom of the flask. The mixture was cooled in a bath of dry-ice and acetone and a solution of 30 g of ammonium chlori.de in 200 ml of water was added with vigorous stirring. The organic layer and four ethereal extracts were combined, dried over potassium carbonate and subsequently concentrated in a water-pump vacuum. Careful distillation of the residue through a 40-cm... 

Acid catalyzed addition of alcohols to alkenes is sometimes used Indeed before Its use as a gasoline additive was curtailed billions of pounds of tert butyl methyl ether (MTBE) was prepared by the reaction... 

Ethers are formed under conditions of the Williamson ether synthesis Methyl ethers of carbohydrates are efficiently prepared by alkylation with methyl iodide m the presence of silver oxide... 

Difluoroethanol is prepared by the mercuric oxide cataly2ed hydrolysis of 2-bromo-l,l-difluoroethane with carboxyHc acid esters and alkaH metal hydroxides ia water (27). Its chemical reactions are similar to those of most alcohols. It can be oxidi2ed to difluoroacetic acid [381-73-7] (28) it forms alkoxides with alkaH and alkaline-earth metals (29) with alkoxides of other alcohols it forms mixed ethers such as 2,2-difluoroethyl methyl ether [461-57-4], bp 47°C, or 2,2-difluoroethyl ethyl ether [82907-09-3], bp 66°C (29). 2,2-Difluoroethyl difluoromethyl ether [32778-16-8], made from the alcohol and chlorodifluoromethane ia aqueous base, has been iavestigated as an inhalation anesthetic (30,31) as have several ethers made by addition of the alcohol to various fluoroalkenes (32,33). Methacrylate esters of the alcohol are useful as a sheathing material for polymers ia optical appHcations (34). The alcohol has also been reported to be useful as a working fluid ia heat pumps (35). The alcohol is available ia research quantities for ca 6/g (1992). 

Hydroxybenzaldehyde has an agreeable aromatic odor, but is not itself a fragrance. It is, however, a useful intermediate in the synthesis of fragrances. The methyl ether of -hydroxybenzaldehyde, ie, -anisaldehyde, is a commercially important fragrance. Anisaldehyde can be made in a simple one-step synthesis from hydroxybenzaldehyde and methyl chloride. Another important fragrance, 4-(p-hydroxyphenyl)butanone, commonly referred to as raspberry ketone, can be prepared from the reaction of -hydroxybenzaldehyde and acetone, followed by reduction (see Flavors and spices). 

Mel, K2CO3, acetone, reflux, 6 h. This is a veiy common and often veiy efficient method for the preparation of phenolic methyl ethers it is also applicable to the. formation of phenolic benzyl ethers. 

The cyclohexylidene ketal, prepared from a catechol and cyclohexanone (AI2O3/ TsOH, CH2CI2, reflux, 36 h), is stable to metalation conditions (RX/BuLi) that cleave aiyl methyl ethers. The ketal is cleaved by acidic hydrolysis (coned. HCl/ EtOH, reflux, 1.5 h, 20°, 12 h) it is stable to milder acidic hydrolysis that cleaves tetrahydropyranyl ethers (1 AHCl/EtOH, reflux, 5 h, 91% yield). ... 

CH3OCH2OCH3, Zn/BrCH2C02Et, 0° CH3COCI, 0-20°, 2 h, 75-85%. A number of methoxymethyl esters were prepared by this method, which avoids the use of the carcinogen chloromethyl methyl ether. 

Bischloromethyl ether has been prepared by saturation of formalin with dry hydrogen chloride by the reaction of paraformaldehyde with phosphorus trichloride or phosphorus oxychloride, by solution of paraformaldehyde in concentrated sulfuric acid and treatment with ammonium chloride or dry hydrogen chloride, and by suspension of paraformaldehyde in seventy or eighty percent sulfuric acid and treatment with chlorosulfonic acid. It is formed together with the asymmetrical isomer when methyl ether is chlorinated and when paraformaldehyde is treated with chlorosulfonic acid. The present method has been published. ... 

Reference may also be made to the synthesis of various alkylated laudanosolines by Schopf, Jackh and Perrey, e.g., laudanosoline 6 7 3 -tribenzyl-4 -methyl ether and laudanosoline 4 -methyl ether, to the preparation of the 3 7-dimethyl ether by Schopf and Thierfelder (1939), and to Robinson and Sugasawa s synthesis of proiosinomenine (4 7-dimethyl ether of laudanosoline). 

Codeine, C18H21O3N. This alkaloid was isolated from opium by Robiquet in 1833. It occurs in opium to the extent of 0-1 to 3 per cent., and is isolated therefrom as the hydrochloride along with morphine hydrochloride in the first stage of Gregory s process. It is a methyl ether of morphine and is usually made from the latter by methylation, for which there are numerous patents. An extensive series of ethers of morphine and its isomerides, including ethers of the alcoholic hydroxyl group (Aeterocodeines) has been prepared by Faris and SmaU. ... 

The 4-methyl ether is a liquid, but all attempts to prepare dimethyl ethers of the two known dihydrothebainols failed the relationship... 

Oxyacanthine contains three methoxyl groups, and one phenolic hj droxyl group is indicated by the preparation of an 0-benzoyl derivative, a potassium derivative and a methyl ether (identical with trilobamine methyl ether, p. 357) yielding a hydroehloride,. 2HC1, m.p. 

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