Hydroxyazole scaffold-based Plasmodium falciparum dihydroorotate dehydrogenase inhibitors : Synthesis, biological evaluation and X-ray structural studies

• Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH) has been clinically validated as a target for antimalarial drug discovery, as a triazolopyrimidine class inhibitor (DSM265) is currently undergoing clinical development. Here, we have identified new hydroxyazole scaffold-based PfDHODH inhibitors belonging to two different chemical series. The first series was designed by a scaffold hopping strategy that exploits the use of hydroxylated azoles. Within this series, the hydroxythiadiazole 3 was identified as the best selective PfDHODH inhibitor (IC50 12.0 μM). The second series was designed by modulating four different positions of the hydroxypyrazole scaffold. In particular, hydroxypyrazoles 7e and 7f were shown to be active in the low μM range (IC50 2.8 and 5.3 μM, respectively). All three compounds, 3, 7e and 7f showed clear selectivity over human DHODH (IC50 > 200 μM), low cytotoxicity, and retained micromolar activity in P. falciparum-infected erythrocytes. The crystallographic structures of PfDHODH in complex with compounds 3 and 7e proved their binding mode, supplying essential data for future optimization of these scaffolds.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Läkemedelskemi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Medicinal Chemistry (hsv//eng)

NATURVETENSKAP  -- Biologi -- Strukturbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Structural Biology (hsv//eng)

NATURVETENSKAP  -- Kemi -- Organisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Organic Chemistry (hsv//eng)

Nyckelord

Bioisosterism

Dihydroorotate dehydrogenase (DHODH) inhibitors

Malaria

Plasmodium falciparum

Pyrazole

Scaffold hopping

X-ray-crystallography

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