4.8- Dimethoxy-6-methyl-1 -naphthols

Naphthalenic compounds such as 4,8-dimethoxy-6-methyl-1-naphthol can be oxidatively coupled essentially by way of a cyclohexadienone. The naphthol... 

Thallium trinitrate oxidi2es naphthols and hydroquinone monoethers, respectively, to quinones and 4,4-diaIkoxycyclohexa-2,5-dienones, eg, 4,4-dimethoxy-2-methyl-2,5-cyclohexadienone [57197-11 -2] (108) (111,112). The yield of (108) is 89%. Because the monoacetal is easily converted to the quinone, the yield of 5-hydroxy-l,4-naphthoquinone [481-39-0] is 64%. 

Various 3-methylcoumarilic acids substituted in the benzene ring by alkyl or methoxyl groups have been thus prepared, then decarboxylated to the corresponding benzofurans, ° ° e.g., 3-methyl-4,7-dimethoxy-benzofuran 2-naphthol leads to 3-methylnaphtho[2,l-6]furan (79), guaiacol to ethyl 7-methoxy-3-methyl coumarilate. ... 

Oxidation of 1-naphthol methyl ether A mixture of hydrogen peroxide solution (1.65 ml, containing 0.0165 mole of the peroxide) and formic acid (25 ml) is added during 90 min to a stirred solution of the ether (2.37 g, 0.015 mole) in 98-100% formic acid (75 ml) at 40°. After a few minutes the solution becomes red, and precipitation of crystals begins within 30 min. The mixture is stirred for 15 min after addition of the peroxide-formic acid solution and is then set aside at room temperature for 12 h. The crystals of 4,4/-dimethoxy-l,l/-bi-naphthalene are collected and washed with a little ethanol, then having m.p. 256-257° (l-35g). Concentrating the mother-liquor gives a small further batch (0.3 g). The total yield is 70%. 

The (S) enantiomer of l,l -bis-2-naphthol (9) 2,2 -dimethoxy-l,T-binaph-thyl, and l,T-binaphthyl-2,2 -diyl hydrogen phosphate were preferentially included by heptakis(2,3,6 tri-0-methyl)-/ -CD [82]. Addition of CD to the (S)-enantiomer caused fluorescence enhancement higher than that observed for the (J )-enantiomer. Moreover, the complex between the trimethyl- -CD and (S)-9 was found to have a stoichiometry of 2 1 while the complex with (J )-g has 1 1 stoichiometry. Unsubstituted jS-CD did not give enantioselec-tive complexation. 

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