(i). The influence of polar substituents on
optical rotatory powers of L-menthyl derivatives lias
been extended to include the L-menthyl ethers of both
aliphatic and aromatic types.
(ii). The effect of ionlsation on the rotatory power
of ethers containing acidic, and probably also basic,
substituents is in agreement with prediction.
(lil). Improved methods are described for the preparation of L-menthoxyacetic acid, L-menthyl methyl
ether, and potassium and sodium aenthoxides.
(iv). In some cases the influence of solvents on the
rotatory power of the L-menthyl ethers is in agreement with the polarity of the solvent, highly polar
solvents tending to reverse the characteristic effect
of the substituents in the optically active molecule.
In other cases the solvent changes are small and show
(v). L-Menthyl 2:4-dinitrophenyl ether is found to
be definitely anomalous in solvents of low polarity
but its dispersion becomes normal, although complex
in solvents of high polarity. This change is
discussed in connection with the properties of other
ortho-substituted benzoic derivatives..