Isolation and characterization of isomers of pyrrole-hydrazones with possible tuberculostatic activity. Comparison of methods for separation

personАвтори: A. Bijev, I. Nencheva, M. Georgieva


Hydrazones are a big class of organic compounds, possessing diverse biological activity. Due to the presence of a double bond in their structure, geometrical isomerism is very characteristic for them. Development of a suitable method for separation of geometric isomers thereof will be of essence for future investigations. Two methods for separation of the geometrical isomers of a previously reported hydrazone 11о were compared: preparative TLC chromatography and fractional recrystallization, taking into account their simplicity and expeditiousness. TLC was performed on 2 mm Silica gel/Glass plaque. In order to assure better separation, a gradient elution was applied. Both isomeric forms of hydrazone 11o were successfully separated by TLC preparative chromatography and further characterized and proved by IR and 1H-NMR spectral analysis. The attempt to isolate the isomers of hydrazone 11o by the second method was unsuccessful. Thus more effective and more applicable appears to be the separation with preparative TLC chromatography.

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