Catechol dimethyl ether

Catechol diethyl ether Catechol dimethyl ether >240 153,328... 

Catechol dimethyl ether, AN62 Catechol monoethyl ether,... 

Alvarez-Manzaneda et al. [5] have developed a synthetic strategy toward the tetracyclic marine metabolite puupehenones involving a FC reaction with enone 25, a common enantiopure nordri-mane synthon utilized in terpenoid synthesis, as the electrophilic partner (Scheme 2.4). The reaction is carried out in the presence of the cationic resin Amberlyst A15 to afford ketone 27 in high yield and with complete diastereoselectivity. The reaction only works with highly activated arenes such as 26, as neither anisole nor catechol dimethyl ether reacted under identical conditions. Ketone 27 can be straightforwardly transformed into triflate 30, which is an intermediate in the synthesis of puupehenone-related metabolites such as puupehenol (31). 

Outline several syntheses of 50. Use aq clic starting materials. Use catechol dimethyl ether as a starting material. (Morphine-8)... 

The dimethyl ethers of hydroquiaones and 1,4-naphthalenediols can be oxidized with silver(II) oxide or ceric ammonium nitrate. Aqueous sodium hypochlorite under phase-transfer conditions has also produced efficient conversion of catechols and hydroquiaones to 1,2- and 1,4-benzoquiaones (116), eg, 4-/-butyl-l,2-ben2oquinone [1129-21-1] ia 92% yield. 

Equimolar quantities of benzhydrol and the phosphorane (3a) were also reacted in dimethyl sulphoxide solution. Apart from bis(benzhydryl) ether (18%) and catechol monobenzhydryl ether (39%), a small amount of benzophenone (17%) was obtained. It was shown that, in the absence of phosphorane, benzhydrol is not oxidised to benzophenone by dimethyl sulphoxide. Reaction similar to that outlined in Scheme 1 is a likely possibility. Again, the alcohol is activated by reaction with the phosphorane toward nucleophilic attack, in this case by dimethyl sulphoxide. Significantly, oxidation of alcohols by dimethyl sulphoxide is usually carried out using the Pfitzner-Moffatt reagent (dicyclohexyl carbodiimide and anhydrous phosphoric acid in dimethyl sulphoxide) (13) whereas the reaction using the phosphorane (3a) is carried out under neutral conditions. Unfortunately, however, attempts to improve the yield of benzophenone have hitherto failed. 

The reaction of ( + )-bulbocapnine methyl ether (42) with excess boron trichloride in methylene chloride containing 0.3% ethanol produces the catechol (43) together with the monophenol (44). However, with boron tribromide, it is the diphenol (45) which is produced. Both compounds (44) and (45) can be O-methylated with diazomethane to the dimethyl ether (46), and hydrolysis of (46) with dilute hydrochloric acid leads to (+)-corytuberine (47).43 Alternatively, methylation of (43), using diazomethane, affords (+)-corydine methyl ether (48). 

Pyrogallol-1,3-dimethyl ether (3 in Fig. 6.6.1) is demethylated to pyrogallol-l-methyl ether (4) which in turn is demethylated to pyrogallol (5) by the NE treatment. The rates for demethylating 3 to 4 and 4 to 5 (Fig. 6.6.1) were found to be greater than the rate for demethylating guaiacol to catechol, as shown... 

Fig.6.6.9. Gas chromatogram of NE products. 1 Guaiacol 2 catechol 3 pyrogallol-1,3-dimethyl ether 4 pyrogallol-l-methyl ether 5 pyrogallol 6 internal standard (bibenzyl) 7 diphenyl ether...

Applying the same GC separation conditions described above, calibration curves are made for guaiacol, catechol, pyrogallol-1,3-dimethyl ether, pyrogallol-l-methyl ether, and pyrogallol using the authentic compounds. For each compound, a linear relationship is established between (Wp/W ) and (Ap/A ), as shown in Eq. (1). 

The same intermediate (A) has led to the synthesis of urushiols by Japanese workers and with 3-(8-oxooctyl)veratrole has been employed firstly for the synthesis of the dimethyl ethers of 3-[(8Z,11Z,14)-pentadecatrienyl- and 3-[(8Z,11E,13E)-pentadecatrienylurushiol (ref.160). Secondly a related procedure (ref. 161), has been used for the free phenol, 8(Z),11(Z),14-urushiol by way of the diacetate of the ArCg intermediate employed earlier, (ref. 150, 151) namely 3-(8-oxooctyl)catechol diacetate. This was prepared by the modified synthetic route depicted rather than by semi-synthesis from a natural product. 

Using methyl ethers of di- and tri-hydric phenols, selective mono-demethylation occurs, e.g. resorcinol monomethyl ether is obtained from resorcinol dimethyl ether and sodium ethanethiolate in DMF. An exception is pyrogallol trimethyl ether which afforded pyrogaUol 1-monomethyl ether in high yield. Methylene ethers, such as methylenedioxybenzene, can be quantitatively converted to catechol, via the intermediate formation of ethyl o-hydroxyphenoxymethyl sulphide . 

Catechol monoethyl ether 4858 2-Chloro-h/, Af-dimethyl-10H- Chlorotrianisene 10695... 

Quinacetophenone is similarly monomethylated with methyl iodide-potassium carbonate, but the dimethyl ether is formed with excess dimethyl sulphate and caustic soda [8]. Methyl-ation of catechol groups can be prevented by carrying out the reaction in the presence of a borate salt. A useful preparation of 3-0-methylgallic acid (17) is based on this principle [33]. 

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