Jens Schamberger

Rendezvous in chemical space? Comparing the small molecule compound libraries of Bayer and Schering

Here, we compare the entire compound collections of Bayer HealthCare and Schering AG with respect to structural identities, similarities and physico-chemical properties. We discuss possible consequences stemming from unexpected findings in light of new collaborative models in pharmaceutical research.

Total Synthesis and Initial Structure―Activity Relationships of Longicatenamycin A

Natural products have provided the majority of lead structures for marketed antibacterials. In addition, they are biological guide principles to new therapies. Nevertheless, numerous “old” classes of antibiotics such as the longicatenamycins have never been explored by chemical postevolution. Longicatenamycin A is the first defined longicatenamycin congener that has been totally synthesized and tested in pure form. This venture required the de novo syntheses of the non‐proteinogenic amino acids (2S,3R)‐β‐hydroxyglutamic acid (HyGlu), 5‐chloro‐D‐tryptophan (D‐ClTrp), and (S)‐2‐amino‐6‐methylheptanoic acid (hhLeu). In the key step, the sensitive HyGlu building block was coupled as a pentafluorophenyl active ester to the unprotected H‐D‐ClTrp‐Glu‐hhLeu‐D‐Val‐D‐(Cbz)Orn‐OH fragment. This first total synthesis of longicatenamycin A provided new congeners of the natural product (deacetyllongicatenamycin, dechlorolongicatenamycin, and longicatenamycin‐A‐amide).

Potent and Selective Human Neutrophil Elastase Inhibitors with Novel Equatorial Ring Topology: In Vivo Efficacy of the Polar Pyrimidopyridazine Bay-8040 in a Pulmonary Arterial Hypertension Rat Model.

Human neutrophil elastase (HNE) is a key driver of inflammation in many cardiopulmonary and systemic inflammatory and autoimmune conditions. Overshooting high HNE activity is the consequence of a disrupted protease–antiprotease balance. Accordingly, there has been an intensive search for potent and selective HNE inhibitors with suitable pharmacokinetics that would allowing oral administration in patients. Based on the chemical probe BAY‐678 and the clinical candidate BAY 85‐8501 we explored further ring topologies along the equator of the parent pyrimidinone lead series. Novel ring systems were annulated in the east, yielding imidazolo‐, triazolo‐, and tetrazolopyrimidines in order to ensure additional inhibitor–HNE contacts beyond the S1 and the S2 pocket of HNE. The western annulation of pyridazines led to the polar pyrimidopyridazine BAY‐8040, which combines excellent potency and selectivity with a promising pharmacokinetic profile. In vivo efficacy with regard to decreasing cardiac remodeling and amelioration of cardiac function was shown in a monocrotaline‐induced rat model for pulmonary arterial hypertension. This demonstrated in vivo proof of concept in animals.