Four configurational isomers of 6-hydroxymethyl-3-isopropyl-4-tetradecylpiperazin-2-ones (4-7), which were designed based on information obtained from the biologically active conformation of teleocidins and benzolactams, were synthesized and evaluated for their ability to compete with [3H]phorbol 12,13-dibutyrate in a PKC8 binding assay. Among the compounds, the 3S,6S-isomer (5) showed moderate binding affinity, 8-30 fold more potent than for the other isomers. This indicates that the relative position of the hydrogen-bonding sites and hydrophobic regions of 5 fits into the cavity of PKC5 binding site. Compound 5 provides a conformationally constrained analogue of diacylglycerol. © 1997 Elsevier Science Ltd.