X-Ray Investigation of Crystal and Molecular Structures in the Caryophyllene Series

Todd, George (1952) X-Ray Investigation of Crystal and Molecular Structures in the Caryophyllene Series. PhD thesis, University of Glasgow.

Abstract

With a view to establishing directly the molecular constitution of the sesquiterpene, beta-caryophyllene, an x-ray study has been made of certain of its crystalline derivatives. beta-caryophyllene dihydrochloride. This is a dicyclic compound containing the structure of the parent, beta-caryophyllene, from which it is obtained by the addition of two molecules of HCl. The substance has been found to possess the space group P2(1) with two molecules per asymmetric unit. Attempts have been made to prepare the corresponding beta-caryophyllene dihydrobromide derivative in order to obtain the structure of the compound directly by means of the isomorphous replacement method. It has not so far been possible to prepare this derivative. beta-caryophyllene bromide and chloride. beta-caryophyllene may be acid ring-closed and hydrated to form a tricyclic derivative, beta-caryophyllene alcohol. This may be halogenated to yield isomorphous bromo and chloroderivatives without stereochemical or structural change. beta-caryophyllene bromide and chloride have been studied by the method of x-ray crystal analysis, and the structure of the molecule obtained directly by means of the isomorphous replacement method. The results confirm the structure recently suggested on the basis of organic chemical degradation evidence : In addition, this work in establishing the structure of the chloride precludes all but the formulation shown for the parent compound---beta-caryophyllene. Additional stereochemical information obtained from the x-ray analysis is as follows: a) the six-membered ring possesses the trans-hexane skeleton. b) the seven-membered ring is cis-, with atoms 5, 6, and 12 on the same side. c) the union of the four-membered ring to the seven-membered ring is trans- with the hydrogen atoms on carbons 2 and 5 projecting in opposite directions.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Molecular chemistry, Organic chemistry
• Date of Award: 1952
• Depositing User: Enlighten Team
• Unique ID: glathesis:1952-78922
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 28 Feb 2020 12:09
• Last Modified: 28 Feb 2020 12:09
• URI: https://theses.gla.ac.uk/id/eprint/78922