<jats:title>Abstract</jats:title><jats:p>Using a biological screening with a HIV‐1/MT‐4 cell assay indicating antiviral activity and cell toxicity, we detected and isolated a new inhibiting metabolite from gliding bacteria, thiangazole (<jats:bold>1</jats:bold>). The structure of <jats:bold>1</jats:bold> was determined by spectroscopic methods to be a tris(thiazoline) derivative, showing a remarkable similarity to tantazole B (<jats:bold>2</jats:bold>). Chemical degradation and comparison with a synthetically prepared reference compound as well as with the degradation product from <jats:bold>2</jats:bold> furnished the (5<jats:italic>R</jats:italic>,8<jats:italic>S</jats:italic>,11<jats:italic>S</jats:italic>) configuration of the asymmetric centers in <jats:bold>1</jats:bold>.