Edinburgh Research Archive

The influence of substitution by the methoxy group on the optical rotatory powers of the menthyl naphthoates

Abstract

1. The introduction of a methoxy group into any position adjacent to the carboxyl residue of the menthyl naphthoates leads to diminution in rotatory power, as in the case of the corresponding benzoic esters of menthol and of sec.-(β-octyl alcohol.
2. A similar strong decrease in rotation is found when the methoxy group is in the peri posi­tion to the carboxy group.
3. A considerable increase in rotation results when the methoxy group occupies the deposi­tion in the L-naphthoic ester. This re­sembles the influence of para substitution in the benzoic esters.
4. An unexpected case of demethylation has been observed, namely the convention of L-methoxy-L-carboxy-diphenyl into the lactone of the corresponding hydroxy acid on treatment with thionyl chloride.
5. It has been found that the menthyl esters of 3-methoxy-2-naphthoic acid and of 8-methoxy-1-naphthoic acid exhibit triboluminescence, whilst the isomeric menthol 4-methgxp- and 2-methoxy-l-naphthoates do not show this property.

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