Three new derivatives of 3-amino-1,2-propanediol have been synthesized. Full assignments of signals in their 1H- and 13C-NMR spectra are given. The influence of these compounds on the cardiovascular system in the anaesthetized rat was examined. In contrast to CGP 12177 which induced a strong increase in heart rate and a slight increase in blood pressure, compounds 1, 2 and 3 x HCl at doses up to 1 micromol/kg and compound 3 at doses of 0.01 and 0.1 micromol/kg did not change the cardiovascular parameters. The highest dose of compound 3-1 micromol/kg caused a very short-lasting decrease in heart rate (by 14%) and in blood pressure (by 25%).