クロラムフェニコール長鎖状エステルのPolymorphism (第2報)

その構造論的研究

抄録

From the consideration of X-ray diffraction, infrared absorption spectra, and various transition conditions of long-chain esters of chloramphenicol, and some assumptions were made on their crystal structure.
1) According to X-ray diffraction, all-trans configuration for the long-chain portion of the β-form molecule results in good agreement between the molecular models and the long axis by X-ray measurement. In the case of α-form, the long axis of the crystal cannot be explained unless the molecule is assumed to have some cis linkages or the long chain part is a trans structure but deeply twined with each other.
2) Infrared absorption spectra suggest that the α-form is closely resembled to a solution state and crystals with a cis configuration, having distorted molecule, may be assumed. The β-form is considered to have a higher order molecular arrangement as a crystal and it is convenient to assume an all-trans configuration by X-ray measurement.
3) Stability of the β-form can be assumed form the measurement of melting point and specific gravity. On the other hand, similarity to the α-form and solution state (or amorphous state) as found from transition conditions and these agree well with the above two measurements.