Studies on the dependence of optical activity on chemical constitution

Summary

The rotatory dispersion ofd-camphor-β-sulphonyl phenylamide,d-camphor,-β-sulphonyl tolyl (o-, m- andp-) amides andd-camphor-β-sulphonyl naphthylamides (α- and β-) have been determined in 7 solvents for 13 wavelengths (λ=6708 Å to λ=4358 Å) in the visible region of the spectrum. It is found to be ‘simple’ as it can be expressed by theone-term Drude’s equation, [a]_λ =k/γ² - γ₀ ². It is controlled generally by a low frequency corresponding to the ketonic group of camphor and sometimes by a high frequency ‘characteristic’ of saturated molecules. In solvents oflow dielectric constants such as ethyl acetate, chloroform and benzene, the high frequency corresponding to the saturated molecules sometimes replaces the low frequency pertaining to the ketonic group. The effect of position isomerism and the influence of the solvent on the rotatory power have been also discussed.

d-Camphor-β-sulphonyl-phenylamide exists in dimorphic form (α and β). This is established by the identity of their rotatory dispersions and their mutual transformation. A new method for the determination of Transformation (Transition) Temperature of the dimorphic forms, based on Roozeboom’s mixed melting point-composition diagram, has been developed. By the application of this method the temperature of Transformation of α-into β-form, in this case, is found to be 118–8° C.