Isomeric methoxyphenols

Two other alkoxyphenols are the isomeric 4-allyl- and 4-(l-propenyl)-2-methoxyphenols with the ancient enthalpies of combustion of 5384.4 and 5346.8 kJ mol. We are automatically troubled by these values. The 38 kJ mol derived difference between the enthalpies of formation of the two isomers is rather much larger than the ca 22 kJ mol derived for their oxygen-defunctionaUzed counterparts allyl and 1-propenylbenzene. 

The literature value given for the mp of 2-methyl-4-methoxyphenol is 70-71 deg C. The literature value given for the mp of the isomeric 3-methyl-4-methoxyphenol is 44-46 deg C. This phenol, on ethylation, gives 2-ethoxy-5-methoxytoluene, which leads directly to the 2-carbon 2CD-5ETO (one of the Tweetios) and the 3-carbon Classic Lady IRIS. 

A new synthesis of ( )-lycoramine (40) (dihydrogalanthamine) has been reported by Schultz and co-workers (Scheme 4). The epoxide (33) was obtained from cyclohexane-1,3-dione enol ether (32) in five high-yield stages. The aryl ring was then introduced by base-catalysed reaction of the epoxide with 5-carbo-methoxy-2-methoxyphenol two isomeric enones (36) and (37) were formed,... 

Methoxy-2,2-dimethylchromene (23.6) and benzofuran 23.2 were also synthesized by alkylation of 4-methoxyphenol to 2-(3-methyl-2-butenyl)-4-methoxyphenol (22.1) followed by acid catalyzed cyclization of the corresponding epoxide 22.2 to a mixture of isomeric compounds 23.3 and 23.7. Dehydration of alcohol 23.7 with / -TsOH gave 23.6, while NBS dehydrogenation of 23.3 afforded 23.2 140). 

Methoxy derivatives of divalent phenols such as guaiacol react like simple monovalent phenols, forming methylol and methylene derivatives. Euler and co-workers- isolated vanillyl alcohol (methjdolguaiacol) and a di-methylol derivative of a methylene-bis-methoxyphenol from the products obtained by reacting guaiacol with formaldehyde under alkaline conditions. Under acidic conditions tw o isomeric methylene-bis-methoxyphenols were obtained. 

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