Dimethoxy methanol

The oxidative reaction of furan with bromine in methanol solution or an electrochemical process using sodium bromide produces 2,5-dimethoxy-2,5-dihydrofuran (19), which is a cycHc acetal of maleic dialdehyde. The double bond in (19) can be easily hydrogenated to produce the corresponding succindialdehyde derivative. Both products find appHcation in photography and as embalming materials, as well as other uses. 

Thiophenecarboxaldehyde [498-62-4] has been commercially available (35) via carbonylation of 2,5-dimethoxy-2,5-dihydrofuran, followed by treatment with hydrogen sulfide, which introduces the sulfur atom with loss of methanol, inducing aromaticity and producing 3-thiophenecarboxaldehyde directly. 

Dissolve 0.5 g blue tetrazolium (3,3 -(3,3 -dimethoxy-4,4 -biphenylylene)-bis(2,5-diphenyl-2H-tetrazolium)-chloride) in 100 ml methanol. 

This with potassium hydroxide in methanol forms de-OiV-dimethylarmepavine, m.p. 86-7°, (B. HCl, m.p. 229-30°) of which the methiodide, m.p. 233-4°, on treatment with alkali decomposes into trimetHylamine and a -p-anisyl-/3-(3 4-dimethoxy- 6 - vinylphenyl) -ethylene, m.p. 79°. The latter is oxidised by permanganate in acetone to anisic and m-hemipinic acids. With ethyl sulphate and alkali, armepavine gives 0-ethylarmepavine, an oil, which permanganate oxidises to p-ethoxybenzoic acid. Armepavine is similarly oxidised to p-hydroxybenzoic acid and l-keto-6 7-dimethoxy-2-methyl-1 2 3 4-tetiahydrowoquinoline and is therefore 6 7-dimethoxy-l-p-hydroxybenzyI-2-methyI-l 2 3 4-tetrahydrowoquinoline, i.e., it is laudanosine (p. 187) with MeO. at C replaced by H and MeO at C changed to HO. ... 

A solution of 1.0 g of 3,17-androstandione in 50 ml of methanol and containing 1 g of selenium dioxide, was allowed to remain in an ice-chest overnight. The formed 3,3-dimethoxy-androstan-17-one was not separated. 1 g of solid potassium hydroxide and 2.5 g of sodium borohydride in 2.5 ml of water were added and the mixture allowed to react at room temperature for 24 hours. The solution was then poured into a large excess of water, extracted... 

There have been very few examples of PTV derivatives substituted at the vinylene position. One example poly(2,5-thienylene-1,2-dimethoxy-ethenylene) 102 has been documented by Geise and co-workers and its synthesis is outlined in Scheme 1-32 [133]. Thiophene-2,5-dicarboxaldehyde 99 is polymerized using a benzoin condensation the polyacyloin precursor 100 was treated with base to obtain polydianion 101. Subsequent treatment with dimethyl sulfate affords 102, which is soluble in solvents such as chloroform, methanol, and DMF. The molar mass of the polymer obtained is rather low (M = 1010) and its band gap ( ,.=2.13 eV) is substantially blue-shifted relative to PTV itself. Despite the low effective conjugation, the material is reasonably conductive when doped with l2 (cr=0.4 S cm 1). 

However, under the same conditions, 6-azidoquinazoline (32) yields the acid-sensitive 5.7-dimethoxy-8,9-dihydro-5//-pyrimido[5,4-c]azcpine (34 16%) by a 1,4-addition of methanol to the initially formed 7-methoxy-9//-pyrimido[5,4-c]azepine (33).153... 

An elegant extension of these ring expansions involving diazidonaphthalenes has been reported. Early results on the photolysis of 1,8-diazidonaphthalene (14) indicated the formation of benz[t d]indazole (17).176 However, it has since been found that photolysis of the diazide in sodium methoxide-methanol/dioxane solution for a short period (20 -40 min) yields, in addition to the benz[c,d]indazole (17, 40%), a mixture of 9-azido-l-methoxy-5//-2-benzazepine (15 15-20%) and l,10-dimethoxy-5,5a-dihydroazepino[3,4-c]azepine (16 10-15%).117... 

Azidoquinoline (4c) can be irradiated in the presence of sodium methoxide to give 2,3-dimethoxy-2,3-dihydro-l//-l,4-benzodiazcpine (7). which undergoes elimination of methanol on heating lo provide 3-methoxy-3//-l,4-benzodiazepine (6c).218... 

Dimethoxy-2- 1 -[2-(tetrahydropyran-2-yloxy)ethyl]vinyl -l, 3.6-oxadiazepine (4 vide supra) isomerizes to an imidazole 1 or 2 in aqueous methanol.320... 

A solution of 1.3 equiv of alkyllithium in hexane is added to a mixture of 1 cquiv of the enimine and 1.4equiv of (1 R,2R)-l,2-dimethoxy-1,2-diphenylethane8 in toluene at — 78°C. The solution is stirred at either — 78 CC or — 45 °C (see table above) for 1 -13 h and then treated with an acetate buffer (pH 4.5) for 12 h. The usual workup gives the aldehyde, which is then reduced with NaBH4 in methanol to give the alcohol. 

The three-necked flask is charged with 750 ml. of formamide, 25 ml. of water, and 50 g. of ammonium chloride (Note 2). The mixture is heated to 180-190° in an oil bath, and 400 g. (3.02 moles) of 4,4-dimethoxy-2-butanone (Note 3) is added dropwise with stirring over the course of 6 hours (Note 4). The flow of cooling water in the reflux condenser should be adjusted to a rate such that the methanol and methyl formate formed during the reaction distil out (Note 5). After all the acetal has been added, heating is continued for 1 hour (Note 6). The mixture is allowed to cool and is poured into 1 1. of IN sodium hydroxide. The resultant solution is extracted with chloroform in a liquid-liquid extractor for 24 hours. The chloroform is separated, dried over sodium sulfate, and removed by distillation through a short column on a steam bath. 

Bromine, reaction with furan in methanol to yield 2,5-dimethoxy-2,5-dihydrofuran, 40, 29... 

Perchlor-styrol kann elektrolytisch in Methanol/l,2-Dimethoxy-athan (1 1) zu (Pen-tachlor-phenyl)-acetylen dechloriert werden. Daneben treten, je nach pH und Elektro-denmaterial, verschiedene Nebenprodukte in wechselnden Ausbeuten auf2 ... 

Bis zu 96% d.Th. 2,3-Diphenyl-butandiol-(2,3) werden bei der Reduktion von Aceto-phenon erhalten in Methanol/Lithiumbromid unterZusatz von (S,S)-(+)-l,4-Bis-[dime-thylamino]-2,3-dimethoxy-butan mit optischen Ausbeuten von bis zu 6,4% (Ammonium-salze fiihren zu vollstandiger Racemisicrung)7. 

Giacomelli et al. constructed 3-propylisoxazole-5-yl-methanol via a [3-1-2] cycioaddition (Fig. 15) [158]. Nitrobutane was converted to nitrile oxide in the presence of 4-(4,6-dimethoxy [1,3,5]triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) and catalytic 4-dimethylaminopyridine (DMAP). Trityl chloride resin-bound propargyl alcohol was employed as the dipolarophile to trap the nitrile oxide, forming the cyclo adduct isoxazole ring under unusually mild conditions (i.e., microwave irradiation at 80 °C for five times 1 min). Disappearance of the starting material was monitored by FT-IR. 

Dissolve SOO mg fast black salt K (Echtschwarzsalz K, diazotized 4-amino-2,5-dimethoxy-4 -nitroazobenzene zinc double salt) in 100 ml water with heating. Filter off any undissolved components. Dilute the filtrate with methanol (l-l-l). 

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. 

KHC03, NaOAc, K2HP04, Na3P04, triethyl amine) and finally sodium carbonate was selected as the base of choice. Fluoride initiated Suzuki coupling with KF was unsuccessful. Dimethoxy ether was selected as the solvent after screening a variety of solvents (acetone, tetrahydrofuran, methanol, isopropyl alcohol, and methyl-i-butyl ether). 

Intermediates generated at an electrode surface may react while still near the electrode. If so, one side of the intermediate may be wholly or partly shielded from attack by other reactants by the electrode itself. Such behavior is particularly common in the electrochemical oxidation of aromatic compounds since, as we have already seen with coumarin, aromatic compounds are generally tightly adsorbed parallel to the electrode surface at potentials positive of the p.z.c. For example, electrochemical oxidation of the stilbenes in alkaline methanol affords a mixture of dl and meso-1,2 dimethoxy-1,2-diphenylethane (1) 10>. It is found that c/s-stilbene affords a mixture of isomers of 1 in which the... 

Figure 11.1 Py/methylation GC/MS chromatograms of lead white pigmented linseed oil paint after 610 °C Curie point pyrolysis assisted with on line methylation using 2.5% methanolic TMAH (the sample and TMAH solution was applied onto a rotating Curie point wire pyrolysis time 6 s, interface 180°C). 1, heptenoic acid, methyl ester 2, heptanoic acid, methyl ester 3, butenedioic acid, dimethyl ester 4, butanedioic acid, dimethyl ester 5, octenoic acid, methyl ester 6, octanoic acid, methyl ester 7, pentenedioic acid, dimethyl ester 8, pentanedioic acid, dimethyl ester 9, nonanoic acid, methyl ester 10, hexanedioic acid, dimethyl ester 11, decanoic acid, methyl ester 12, heptanedioic acid, dimethyl ester 13, octanedioic acid, dimethyl ester 14, 1,2 benzenedicarboxylic acid, dimethyl ester 15, a methyl octanedioic acid, dimethyl ester 16, nonanedioic acid, dimethyl ester 17, a methoxy octanedioic acid, dimethyl ester 18, a methyl nonanedioic acid, dimethyl ester 19, a,a dimethyl nonenedioic acid, dimethyl ester 20a, a methyl nonenedioic acid, dimethyl ester 20b, a,a dimethyl nonanedioic acid, dimethyl ester 21, decanedioic acid, dimethyl ester 22, a methoxy nonanedioic acid, dimethyl ester 23, a methyl decan edioic acid, dimethyl ester 24, undecanedioic acid, dimethyl ester 25, a methoxy decan edioic acid, dimethyl ester 26, pentadecanoic acid, methyl ester 27, dodecanedioic acid, dimethyl ester 28, hexadecanoic acid, methyl ester 29, heptadecanoic acid, methyl ester 30, octadecanoic acid, methyl ester 31,8 methoxy 9 octadecenoic acid, methyl ester 32, 11 methoxy 9 octadecenoic acid, methyl ester 33, 9 methoxy 10 octadecenoic acid and 10 methoxy 8 octadecenoic acid 34, 9 oxo octadecanoic acid, 10 oxo octadecanoic acid 35, 9 epoxy octadecanoic acid 36, eicosanoic acid, methyl ester 37, 9,10 dimethoxy octadecanoic acid, methyl ester 38, docosanoic acid, methyl ester. Reprinted from J. Anal. Appl. Pyrol., 61, 1 2, van den Berg and Boon, 19, Copyright 2001, with permission from Elsevier...

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