Design, synthesis, molecular modeling, and biological evaluation of acrylamide derivatives as potent inhibitors of human dihydroorotate dehydrogenase for the treatment of rheumatoid arthritis

Human dihydroorotate dehydrogenase(DHODH) is a viable target for the development of therapeutics to treat cancer and immunological diseases, such as rheumatoid arthritis(RA), psoriasis and multiple sclerosis(MS). Herein, a series of acrylamide-based novel DHODH inhibitors as potential RA treatment agents were designed and synthesized. 2-Acrylamidobenzoic acid analog 11 was identified as the lead compound for structureeactivity relationship(SAR) studies. The replacement of the phenyl group with naphthyl moieties improved inhibitory activity significantly to double-digit nanomolar range.Further structure optimization revealed that an acrylamide with small hydrophobic groups(Me, Cl or Br)at the 2-position was preferred. Moreover, adding a fluoro atom at the 5-position of the benzoic acid enhanced the potency. The optimization efforts led to potent compounds 42 and 53-55 with IC50 values of 41, 44, 32, and 42 nmol/L, respectively. The most potent compound 54 also displayed favorable pharmacokinetic(PK) profiles and encouraging in vivo anti-arthritic effects in a dose-dependent manner.

Novel and potent inhibitors targeting DHODH are broad-spectrum antivirals against RNA viruses including newly-emerged coronavirus SARS-CoV-2

Emerging and re-emerging RNA viruses occasionally cause epidemics and pandemics worldwide,such as the on-going outbreak of the novel coronavirus SARS-CoV-2.Herein,we identified two potent inhibitors of human DHODH,S312 and S416,with favorable drug-likeness and pharmacokinetic profiles,which all showed broad-spectrum antiviral effects against various RNA viruses,including influenza A virus,Zika virus,Ebola virus,and particularly against SARS-CoV-2.Notably,S416 is reported to be the most potent inhibitor so far with an EC5o of 17 nmol/L and an SI value of 10,505.88 in infec-ted cells.Our results are the first to validate that DHODH is an attractive host target through high antiviral efficacy in vivo and low virus replication in DHODH knock-out cells.This work demonstrates that both S312/S416 and old drugs(Leflunomide/Teriflunomide)with dual actions of antiviral and immuno-regulation may have clinical potentials to cure SARS-CoV-2 or other RNA viruses circulating worldwide,no matter such viruses are mutated or not.