3-Methoxyphenol ether

In the first synthesis of T, the diphenyl ether was formed from -methoxyphenol and 3,4,5-triiodonitrobenzene. The nitro group was replaced by a nitril which was then built up into the alanyl side chain by a series of steps (10). 

Methoxyphenol. This ether is prepared by methylating 1,2-dihydroxybenzene. It is useful as an antioxidant for fats, oils, and vitamins, and as a polymerization inhibitor. 2-Methoxyphenol is effective as an antioxidant and inhibitor at levels of 10—100 ppm. 

Polymerization inhibitors are key additives which prevent premature gelation of the adhesive. The foimulator must carefully balance shelf stability and the required cure on demand. Due to its high propagation rate, MMA is difficult to inhibit. Some comments on specific inhibitors follow. The most common inhibitor to be found in component monomers is 4-methoxyphenol, which is also called the methyl ether of hydroquinone. This inhibitor is effective only in the presence of oxygen. A mechanism has been proposed, and is illustrated in Scheme 13 [128]. 

It should be noted that one of these diols, the hydroquinone, did not provide any oligomer in the first step. This was due to the formation of the quinone structure which made it impossible to use hydroquinone directly in the substitution reaction. An alternate method was used to overcome this problem which involved the use of 4-methoxyphenol to obtain the sulfone product, followed by cleavage of the methyl ether to the diol (VIII) with boron tribromide. This set of reactions is outlined in Figure 5. 

Dimethoxy 4-ethoxybenzene. To a solution of 4-ethoxy-3-methoxyphenol (14 g) in 20 ml of MeOH is added a solution of 5.3 g of KOH in MeOH (100 ml), followed by 11.9 g of Mel. The mixture is then refluxed for two hours, then quenched with 3 volumes of H2O, and made strongly basic with 5% NaOH. Extract with ether and evaporate the pooled extracts to get the title ether as a clear oil. Yield 9.7 g. 

As normally supplied, acrylic esters are inhibited to enhance the shelf life. Aside from dissolved oxygen, inhibitors that are deliberately added include phenolic compounds such as hydroquinone (HQ) and p-methoxyphenol (MEHQ, i.e., methyl ether of hydroquinone ). These inhibitors are usually present in concentrations of 50 to 100 parts per million (ppm) by weight. Oxidation products of the phenolic inhibitors may also be present. 

Dimethylthexylsilyl trifluorometh-anesulfonate, 74 using other methods Allyl chloroformate, 9 Benzyl trichloroacetimidate, 32 Bromodimethylborane, 47 Chloromethyl ethyl ether, 75 2,3-Dihydro-1,4-dioxin, 112 p-Methoxyphenol, 181 of aldehydes and ketones as acetals or dithioacetals... 

A unique feature of this procedure is the selective monode-methylation of the dimethyl ether. The scope of this reaction is illustrated6 in part by the preparation in high yield of p-methoxyphenol, guaiacol, and phloroglucinol dimethyl ether from the respective fully O-methylated compounds. An exception is pyrogallol trimethyl ether which affords pyrogallol 1-monomethyl ether in high yield.6... 

A solution of 14 g of the distilled, solid 4-ethoxy-3-methoxyphenol in 20 mL MeOH was treated with a solution of 5.3 g KOH in 100 mL hot MeOH. There was then added 11.9 g methyl iodide, and the mixture was held at reflux temperature for 2 h. The reaction was quenched with 3 volumes H.O, made strongly basic by the addition of 1 volume of 5% NaOH, and extracted with 2x150 mL E O. Pooling the extracts and removal of the solvent under vacuum gave 9.7 g of 2.4-dimethoxy-1-ethoxybenzene as a clear, off-white oil that showed a single peak by GC. An acceptable alternate synthesis of this ether i s the ethylation of 2,4-dimethoxyphenol, whichisdescribedintherecipeforTMA-4. The index of refraction was nD25 = 1.5210. 

A suspension of 106 g 3-iodo-5-nitro-4-hydroxybenzaldehyde in 370 ml dry pyridine was stirred with 70 g benzenesulfonyl chloride for 2 hours at 20°C, whereupon 90 g 4-methoxyphenol was added and boiled for 1 hour. Pyridine was distilled off in vacuum and 2 N HCI was added to the residue and 3 times extracted with ether. The reminder was washed with 2 N NaOH, water and recrystallized from butyl ether. Yield 98 g MP 101°C. 

A general route to phenoxathiins 85 (Z = O, Z = S) utilizes the reaction of diphenyl ethers with sulfur. One route to thianthrene 85 (Z, Z = S) involves reaction of sulfur monochloride with benzene over aluminum chloride. Likewise, tf-methoxyphenol reacts with sulfur dichloride to give, depending on the rate of addition of the reactant, 2,8-dihydroxy-3,7-dimethoxythianthrene 89 or l,6-dichloro-2,7-dihydroxy-3,8-dimethoxythianthrene 90 <1997JCM272>. 

SYNS HYDROQUINONE MONOMETHYL ETHER MEQUINOL p-METHOXYPHENOL MME MONOMETHYL ETHER HTOROQLTNONE L SAF AN-7... 

SYNS m-GUAIACOL m-HYDROXYANISOLE 3-HYDROXYANISOLE m-METHOXYPHENOL 3-METHOXYPHENOL RESORCINOL METHYL ETHER... 

In an analogous fashion, use of the 7r-bonds of vinyl ethers, vinyl sulfides, and electron-rich styrenes as nucleophiles has been developed as a surprisingly versatile anodic C-C bond-forming reaction, particularly for the synthesis of complex neolignan structures. Early controlled-potential electrolysis studies on pam-methoxyphenol and vinyl ethers gave the corresponding dihydrobenzofuran acetals in what is formally a [3 2]-... 

An alternate strategy involved anodic oxidation of /> 7ra-methoxyphenol TBDPS ether derivatives (LXXVIII). The resulting mixed 0-silyl 0-methyl bisketals (LXXIX) underwent selective monohydrolysis of the dimethyl ketal moiety [87]. Alternatively, desi-lylation of LXXIX with B114NF gave dimethyl monoketals of the opposite regiochemistry [Eq. (37)]. This work was in contrast to earlier studies on similar silyl ethers systems, wherein O-Si bond cleavage predominated during electrolysis [88]. 

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