The Absolute Configuration of Pyrazidole

The absolute configuration of 8-methyl-3-(-S-α-phenylethyl)-2,3,3a-S,4,5,6-hexahydro-1H-pyrazino-[3,2,1-jk]carbazole has been established on the basis of the stereospecificity of its ¹H and ¹³C NMR parameters, which, taking into account the synthetic scheme, provides evidence for an S-configuration of the aymmetric C-3a atom in the original ( + )-pyrazidole.