INVESTIGATIONS ON 1-AZABICYCLIC COMPOUNDS. 25. STEREOCHEMISTRY, HYDROGEN BONDS, AND GAS-LIQUID CHROMATOGRAPHY OF PYRROLIZIDINE ALCOHOLS

Abstract

Data have been summarized of several studies on the separation of isomeric pyrrolizidine alcohols by GLC using liquid polar stationary phases. It was shown that the order of emergence of isomers from the chromatographic column is determined to a significant extent by competition of intermolecular hydrogen bonds formed in the sorbate–sorbent systems and intramolecular hydrogen bonds in the molecules of the same pyrrolizidine alcohols. The preference for one or other type of hydrogen bond depends on the stereochemistry of the pyrrolizidine alcohols. Analysis of the geometric conditions for the formation of intramolecular hydrogen bonds in the investigated compounds in conjunction with chromatographic resolution data enables their configurations to be assigned. The anomalously short retention times of highly strained 5-hydroxyalkyl-3-methylpyrrolizidines are explained by the existence in them of a bicyclic conformation predominantly with a trans linkage and with favorable geometric conditions for forming intramolecular hydrogen bonds in them.

How to Cite
Skvortsov, I. M. Chem. Heterocycl. Compd. 2003, 39, 493. [Khim. Geterotsikl. Soedin. 2003, 574.]

For this article in the English edition, see DOI https://doi.org/10.1023/A:1024769531168