Development of (E)-2-((1,4-Dimethylpiperazin-2-ylidene)amino)-5-nitro-N-phenylbenzamide, ML336: Novel 2-Amidinophenylbenzamides as Potent Inhibitors of Venezuelan Equine Encephalitis Virus

Abstract

Venezuelan equine encephalitis virus (VEEV) is an emerging pathogenic alphavirus that can cause significant disease in humans. Given the absence of therapeutic options available and the significance of VEEV as a weaponized agent, an optimization effort was initiated around a quinazolinone screening hit 1 with promising cellular antiviral activity (EC50 = 0.8 μM), limited cytotoxic liability (CC50 > 50 μM), and modest in vitro efficacy in reducing viral progeny (63-fold at 5 μM). Scaffold optimization revealed a novel rearrangement affording amidines, specifically compound 45, which was found to potently inhibit several VEEV strains in the low nanomolar range without cytotoxicity (EC50 = 0.02–0.04 μM, CC50 > 50 μM) while limiting in vitro viral replication (EC90 = 0.17 μM). Brain exposure was observed in mice with 45. Significant protection was observed in VEEV-infected mice at 5 mg kg–1 day–1 and viral replication appeared to be inhibited through interference of viral nonstructural proteins.

β- d - N 4 -Hydroxycytidine Is a Potent Anti-alphavirus Compound That Induces a High Level of Mutations in the Viral Genome

“…In one study, the identified CID15997213 compound demonstrated a strong inhibitory effect on VEEV replication in vitro and in a small animal model via its targeting of the nsP2 protein and ultimately viral RNA replication (14). Some other quinazolinone-derived molecules also exhibited antiviral activity against VEEV (15,16). For example, compound ML336 inhibited several VEEV strains in the nanomolar range in vitro and also protected mice from a lethal VEEV infection.…”

Discovery of a Broad-Spectrum Antiviral Compound That Inhibits Pyrimidine Biosynthesis and Establishes a Type 1 Interferon-Independent Antiviral State

“…VEEV is an RNA virus that causes encephalitis in humans and equids, and effective therapeutics for the disease have not yet been developed. We screened a library of 348,000 small-molecule compounds with a cell-based assay that measured the protection of cells from VEEV-induced cytopathic effect (strain TC-83) and discovered five active compounds (hits) with 50% effective concentrations (EC 50 s) that were better than 15 M. One of these hits and the resulting optimized lead, ML336, turned out to be a DAA that inhibits viral RNA synthesis by targeting the amino terminal domains of viral nonstructural proteins 2 and 4 (8,9).…”

Divergent 2‐Chloroquinazolin‐4(3H)‐one Rearrangement: Twisted‐Cyclic Guanidine Formation or Ring‐Fused N‐Acylguanidines via a Domino Process

“…The utility of this method was further demonstrated for each of the two accessible guanidine structural classes. Plasma stability is one optimization parameter in our antiviral medicinal chemistry program . Mouse plasma stability of around 65 % has been generally observed for a series of benzamidines, and we questioned the stability of the benzamidine functionality towards enzymatic hydrolysis in vivo.…”