Influence of substituents and solvents on the optical rotary power of the L-menthyl ethers

Abstract

(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 no regularity.

(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..