2.5- dimethoxybenzyl alcohol

Dimethoxybenzyl esters prepared from the acid chloride and the benzyl alcohol are readily cleaved oxidatively by DDQ (CH2CI2, H2O, rt, 18 h, 90-95% yield). A 4-methoxybenzyl ester was found not to be cleaved by DDQ. The authors have also explored the oxidative cleavage (ceric ammonium nitrate, CH3CN, H2O, 0°, 4 h, 65-97% yield) of a variety of 4-hydroxy- and 4-amino-substituted phenolic esters. ... 

Another iron porphyrin complex with 5,10,15,20-tetrakis(2, 6 -dichloro-3 -sulfonatophenyl)porphyrin was applied in ionic liquids and oxidized veratryl alcohol (3,4-dimethoxybenzyl alcohol) with hydrogen peroxide in yields up to 83% to the aldehyde as the major product [145]. In addition, TEMPO was incorporated via... 

Reduce 3,5-dimethoxybenzoic acid with lithium aluminum hydride to 3,5-dimethoxybenzyl alcohol (I), to 10.5 g (I) in 100 ml methylene chloride at 0° C add 15 g PBr3 warm to room temperature and stir for one hour. Add a little ice water and then more methylene chloride. Separate and then dry, evaporate in vacuum the methylene chloride. Add petroleum ether to precipitate about 11.5 g of the benzyl bromide (II). To 9.25 g (II), 15 g Cul, 800 ml ether at 0° C, add butyl (or other alkyl)-Li (16% in hexane), and stir for four hours at 0° C. Add saturated NH4C1 and extract with ether. Dry and evaporate in vacuum the ether (can distill 100/0.001) to get about 4.5 g olivetol dimethyl ether (HI) or analog. Distill water from a mixture of 90 ml pyridine, 100 ml concentrated HC1 until temperature is 210° C. Cool to 140 0 C and add 4.4 g (III) reflux two hours under N2. Cool and pour into water. Extract with ether and wash with NaHC03. Make pH 7 and dry, evaporate in vacuum to get 3.8 g olivetol which can be chromatographed on 200 g silica gel (elute with CHC13) or distill (130/0.001) to purify. 

Add with stirring 22.5 g S0C12 in 100 ml ether in 20 ml portions to a solution of 15 g 3,5-dimethoxybenzyl alcohol, 1 ml pyridine and 200 ml ether. Let stand and wash with 2X100 ml cold water separate and dry, evaporate in vacuum the ether to get 16 g 3,5-dimethoxybenzyl chloride (I). Recrystallize from petroleum ether. 16 g (I), 300 ml ethanol, 30 g NaCN, 75 ml water reflux three hours and pour onto 400 g ice. After ice melts, filter and recrystallize precipitate from petroleum ether to get about 14 g 3,5-dimethoxybenzyl CN (II). 5 g 50% NaH in mineral oil wash three times with pentane or hexane fill flask with N2 or argon and add dimethoxyethane or dimethylformamide (freshly distilled from K if possible). Stir and add 9 ml methyl iodide. Carefully add 8 g (II) and stir twelve hours. Add ice water and neutralize with NaHC03 to pH 7-8. Extract with ether and dry, evaporate in vacuum the ether (can distill 170/0.1) to get about 9 g alpha, alpha-dimethyl-3,5-... 

Add 78.5 g of the above benzoate in 300 ml of ether to a stirred suspension of 19 g lithium aluminum hydride in 200 ml of ether at such a rate as to give gentle reflux. After the addition, reflux for 2V2 hours, then cool. Add 50 ml of wet ether and 100 ml dilute sulfuric acid. Evaporate the ether extract in vacuo to get about 60 g of 3,5-dimethoxybenzyl alcohol and recrystallize with ether-pentane. To a cooled, stirred slurry of CrOs and 250 ml pyridine, add 8.4 g of the above alcohol in 25 ml pyridine and after the addition let stand at room temp for 1 hour. Add 60 ml of methanol, let stand 2 hours, and dilute with 500 ml of 5% NaOH and 500 ml ether. Extract the aqueous layer with ether and wash the combined ether layers with water (500 ml), then three 500 ml of 5% sulfuric acid, again with 500 ml water, and then 200 ml saturated NaCl. Dry and evaporate in vacuo to get 7 g 3,5-dimethoxybenzaldehyde. (This benzaldehyde is not much more suspicious to the DEA than the LAH used to make it. It may be cheaper for you to buy than to make.)... 

Olivetol. 3,5-Dimethoxybenzyl alcohol. (This can be made by reducing 3,5-dimethoxybenzoic acid, or it can be purchased.) (10 g) in 100 ml of methylene chloride is cooled to 0° and 15 g of PBrs is added. Warm to room temp and stir for 1 hour, then add a little ice water followed by more methylene chloride. Add petroleum ether to precipitate the benzyl bromide, which is separated off. 9.3 g of the benzyl bromide is put in a flask with 800 ml of dry ether and then add 15 g of copper iodine at 0°. Add butyl lithium (16% in hexane) and stir for four hours at 0°. Add saturated NH4CI and extract with ether. The ether is removed by evaporating in vacuo to give the olivetol dimethyl ether which must be demethylated by one of the methods given in the above formulas. Yield A little over 4 g. Taken from HCA, 52, 1132. 

Lithcoa and standardized by titration against 2, 5-dimethoxybenzyl alcohol... 

Figure 3. Self-condensation of vanillyl alcohol ( 4 ) and 3,4-dimethoxybenzyl alcohol ( 8 ) in acid (11).

Butyllithium in hexane (1.6 M), obtained from Aldrich Chemical Company, Inc., was titrated (using 2,5-dimethoxybenzyl alcohol as the indicator2) just prior to use. 

The Parikh-Doering oxidation provides a very high regioselectivity for the oxidation of alcohols. Oxidation-sensitive functionalities, like indoles,99a,c sulfides,109 and selenides 110 as well as oxidation-sensitive protecting groups, like dithioacetals,111 PMB104 and dimethoxybenzyl ethers109b, do not react. 

Nomially, dry solvents are employed in the oxidation of unsaturated alcohols with DDQ. This is done because DDQ is decomposed by water.94c On the other hand, the use of wet solvents may not be deleterious, as a mixture of CH2CI2 and water is routinely employed for the deprotection of p-methoxybenzyl (PMB)10S and 3, 4-dimethoxybenzyl (DMPM)106 ethers with DDQ, and, when this deprotection leads to an unsaturated alcohol, a prolonged reaction allows a successful oxidation of the alcohol to a ketone.107... 

Hydroxy - 3,5 - dimethoxyphenol. 2,6 - Dimethoxyphenol was converted to 4-hydroxy-3,5-dimethoxybenzyl alcohol by reaction with... 

Olah and co-workers219 have applied Nafion-H in the benzylation of benzene with benzyl alcohols [Eq. (5.83)] and also reported the reaction of benzyl alcohol with substituted aromatics (toluene, xylenes, mesitylene) to yield diphenylmethanes. The reaction is performed under mild conditions and produces the corresponding dibenzyl ethers as byproducts (2-22%). The substrate and positional selectivity in competitive benzylation of benzene and toluene (1 1 molar ratio) was found to be almost the same as observed in solution-phase Friedel-Crafts benzylation with benzyl chloride (AICI3-CH3NO2). Cyclic products 56 and 57 resulting from cyclialkylation were isolated when Nafion-H-catalyzed benzylation was applied to 2-(hydroxymethyl) diphenylmethane and 3,4-dimethoxybenzyl alcohol, respectively. 

Even pentachlorophenol can be degraded with this catalytic system. Another reaction relevant to the paper industry is the degradation of 3,4-dimethoxybenzyl alcohol. This aromatic compound is a model for the lignin fraction, which must be removed to produce white paper. Supported... 

LiP catalyzes the oxidation of 3,4-dimethoxybenzyl alcohol (veratryl alcohol) to veratryl aldehyde. Since this reaction can be easily followed at 310 nm, it is the basis for the standard assay for this enzyme (26,27). The enzyme exhibits normal saturation kinetics for both veratryl alcohol and H202 (28,43). Steady-state kinetic results Indicate a ping-pong mechanism in which H202 first oxidizes the enzyme and the oxidized intermediate reacts with veratryl alcohol (43). The enzyme has an extremely low pH optimum ( 2.5) for a peroxidase (43,44) however, the rate of formation of compound I (kx, Fig. 2) exhibits no pH dependence from 3.0-7.0 (45,46). Addition of excess veratryl alcohol at pH 3.0 results in the rapid conversion of... 

The synthesis of bufotenine itself followed closely upon the proof of its structure. Hoshino and Shimodaira reduced the ethyl ester of 5-ethoxy-indole-3-acetic acid by the Bouveault-Blanc procedure to the corresponding primary alcohol, which was treated with phosphorus tribromide and then dimethylamine, to give the ethyl ether of bufotenine, which was demethylated with aluminum chloride (130). In a later synthesis, 2,5-dimethoxybenzyl cyanide (XXIII) was alkylated by Eisleb s method with dimethylaminoethyl chloride in the presence of sodamide to give l-(2,5-dimethoxyphenyl)-3-dimethylaminopropyl cyanide (XXIV), which was then hydrogenated over Haney nickel to yield 2-(2,5-di-methoxyphenyl)-4-dimethylaminobutylamine (XXV R = Me). De-methylation of this with hydrobromic acid, followed by oxidation of the product (XXV R = H) with potassium ferricyanide yielded bufotenine (XIX) via the related quinone (109). 

Protection of hydroxyl groups (11, 166).- 3.4-Dimethoxybcnzyl ethers are oxidized by DDQ more readily thanp-methoxybenzyl ethers. Moreover, the dimethoxybenzyl ethers of secondary alcohols can be selectively oxidized in the presence of the corresponding ethers of primary alcohols. Benzyl, p-methoxybenzyl, and 3,4-dimethoxybenzyl ethers all undergo hydrogenolysis catalyzed by Pt/C or Pd/C, but selective hydrogenolysis of benzyl ethers is possible with W-2 Raney Ni. 

SYN S 2-AMINO-l -(2,5-DIMETHOXYPHENYL)-l -PROPANOL HYDROCHLORIDE a-(l-AMINOETHYL)-2,5-DIMETHOXYBENZYL ALCOHOL HYDROCHLORIDE p-(2,5-DIMETHOX1THENYL)-p-HYDROXYISO-PROPYL.AMINE HYDROCHLORIDE p-HYDROXY-P-(2,5-DIMETHOXYPHENYL)-ISOPROPYLAi nNE HYDROCHLORIDE PRESSOMIN HYDROCHLORIDE VASO-XINE VASOXINE HYDROCHLORIDE VASOXYL HYDROCHLORIDE... 

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