With the aim of finding newrenininhibitors with improved bioavailability properties, two angiotensinogen transition state analogues 1a and 1b, containing a novel unnaturalaminoacid at the P(2) position, namely the (2R,3S)- and (2S,3S)-2-amino-3-(1,3-dithiolan-2-yl)-3-hydroxypropanoic acid (ADHPA), have been synthesized and tested for humanrenin inhibitory activity and for chemical and enzymatic