Molecular structure in the solid state (X-ray crystallography) and in solution (1H and 13C nuclear magnetic resonance spectroscopy) of 1,3-diazetidines and pentasubstituted biguanides. X-Ray molecular structure of 2,4-bis-(6-methyl-3-methylthio-5-oxo-4,5-dihydro-1,2,4-triazin-4-yl)-5,5-pentamethylene-1,3-diphenylbig anide and 1,3-bis-(p-chlorophenyl)-5-dimethylamino-2,4-bis-(6-methyl-3-methylthio-5-oxo-4,5-dihydro-1,2,4-triazin-4-yl)biguanide

Abstract

The molecular structures of a hexa- and a penta-substituted biguanide have been solved by X-ray crystallography: compound (9c) disubstituted at N(5) by (as) a piperidine ring, and compound (11b) monosubstituted at N(5) by a dimethylamino group. The X-ray structures can be used to explain the ¹H and ¹³C NMR behaviour observed for these and related compounds. Consideration of the intramolecular hydrogen bonds between the NH and CO groups is essential for the determination of the structure and spectroscopic properties of biguanides. In addition, the precursor diazetidines have also been studied by NMR sectroscopy: the Z,Z-isomer is always the most abundant, but minor qantities of the E,E-isomer can be observed.