Discovery of Arylsulfonamide Na1.7 Inhibitors: IVIVC, MPO Methods, and Optimization of Selectivity Profile.

The voltage-gated sodium channel Na1.7 continues to be a high-profile target for the treatment of various pain afflictions due to its strong human genetic validation. While isoform selective molecules have been discovered and advanced into the clinic, to date, this target has yet to bear fruit in the form of marketed therapeutics for the treatment of pain.

Selections and screenings of DNA-encoded chemical libraries against enzyme and cellular targets.

The use of DNA-encoded libraries (DELs) has increased greatly over the last decade, and today a majority of pharmaceutical companies employ the technology. The technology may be applied to most soluble and purified targets. However, standard DEL technology has limitations; some targets are challenging to purify, and it is not possible to directly screen for cellular or biochemical activity.

Synthesis of 1,2-Amino Alcohols by Photoredox-Mediated Decarboxylative Coupling of α-Amino Acids and DNA-Conjugated Carbonyls.

We report a DNA-compatible photoredox decarboxylative coupling of α-amino acids with carbonyl compounds to access DNA-encoded sp-rich 1,2-amino alcohols. The reaction proceeds efficiently for a wide range of DNA-conjugated aldehydes and ketones and provides the desired 1,2-amino alcohols with conversions generally >50%. Additional utility of the developed protocol is demonstrated by one-pot cyclization of DNA-conjugated 1,2-amino alcohols into oxazolidiones and morpholinones.

DNA-Compatible Copper-Catalyzed Oxidative Amidation of Aldehydes with Non-Nucleophilic Arylamines.

We report a DNA-compatible protocol for synthesizing amides from DNA-bound aldehydes and non-nucleophilic arylamines including aza-substituted anilines, 2-aminobenzimidazoles, and 3-aminopyrazoles. The reactions were carried out at room temperature and provided reasonable conversions and wide functional group compatibility. The reactions were also successful when employing aryl and aliphatic aldehydes.

Solution-Phase DNA-Compatible Pictet-Spengler Reaction Aided by Machine Learning Building Block Filtering.

The application of machine learning toward DNA encoded library (DEL) technology is lacking despite obvious synergy between these two advancing technologies. Herein, a machine learning algorithm has been developed that predicts the conversion rate for the DNA-compatible reaction of a building block with a model DNA-conjugate. We exemplify the value of this technique with a challenging reaction, the Pictet-Spengler, where acidic conditions are normally required to achieve the desired cyclization between tryptophan and aldehydes to provide tryptolines.

Copper-Mediated DNA-Compatible One-Pot Click Reactions of Alkynes with Aryl Borates and TMS-N.

We report a DNA-compatible copper-mediated efficient synthesis of 1,2,3-triazoles via a one-pot reaction of aryl borates with TMS-N followed by a click cycloaddition reaction. Employing the binuclear macrocyclic nanocatalyst Cu(II)-β-cyclodextrin, the reactions were performed under mild conditions with high conversions and wide functional group tolerance. We also demonstrate the reaction application toward a one-pot DNA-compatible intramolecular macrocyclization.

Palladium-mediated Suzuki-Miyaura Cross-Coupling Reaction of Potassium Boc-protected aminomethyltrifluoroborate with DNA-Conjugated aryl bromides for DNA-Encoded chemical library synthesis.

A mild reaction for DNA-compatible, palladium promoted Suzuki-Miyaura cross-coupling reaction of potassium Boc-protected aminomethyltrifluoroborate with DNA-conjugated aryl bromides has been developed efficiently. This novel DNA encoded chemistry reaction proceeded well with a wide range of functional group tolerance, including aryl bromides and heteroaryl bromides. Further, the utility our DNA conjugated aminomethylated arene products is demonstrated by reaction with various types of reagents (including amide formation with carboxylic acids, alkylation with aldehydes, and carbamoylation with amines) as would be desired for the production of a DNA encoded library.

DNA Compatible Intermolecular Wittig Olefination for the Construction of α, β-Unsaturated Carbonyl Compounds.

A robust DNA-compatible Wittig reaction mediated by PPhCH has been validated for DNA-conjugated α-chloroacetamides with aldehydes and, alternatively, DNA-conjugated aldehydes with α-halo acetamides or ketones. Further, 2-aminopyridines were acylated with α-chloroacetyl chloride and then reacted with DNA-conjugated aldehydes. Lastly, a pilot library employing our optimized Wittig reaction protocol was synthesized.

A Strategy for the Synthesis of Sulfonamides on DNA.

An efficient method is reported to synthesize sulfonamides on DNA from sulfinic acids or sodium sulfinates and amines in the presence of iodine under mild conditions. This method demonstrates a major expansion of scope of sulfonamide formation on DNA through the utilization of a novel sodium carbonate-sodium sulfinate bifunctional reagent class.

Development of a New Structural Class of Broadly Acting HCV Non-Nucleoside Inhibitors Leading to the Discovery of MK-8876.

Studies directed at developing a broadly acting non-nucleoside inhibitor of HCV NS5B led to the discovery of a novel structural class of 5-aryl benzofurans that simultaneously interact with both the palm I and palm II binding regions. An initial candidate was potent in vitro against HCV GT1a and GT1b replicons, and induced multi-log reductions in HCV viral load when orally dosed to chronic GT1 infected chimpanzees. However, in vitro potency losses against clinically relevant GT1a variants prompted a further effort to develop compounds with sustained potency across a broader array of HCV genotypes and mutants.

Discovery of selective, orally bioavailable, N-linked arylsulfonamide Na1.7 inhibitors with pain efficacy in mice.

The voltage-gated sodium channel Na1.7 is a genetically validated target for the treatment of pain with gain-of-function mutations in man eliciting a variety of painful disorders and loss-of-function mutations affording insensitivity to pain. Unfortunately, drugs thought to garner efficacy via Na1 inhibition have undesirable side effect profiles due to their lack of selectivity over channel isoforms.

Design, synthesis, and biological evaluation of anti-EV71 agents.

Enterovirus 71 (EV71) is a major causative agent of hand, foot and mouth disease (HFMD), which can spread its infections to the central nervous and other systems with severe consequences. In this article, design, chemical synthesis, and biological evaluation of various anti-EV71 agents which incorporate Michael acceptors are described. Further SAR study demonstrated that lactone type of Michael acceptor provided a new lead of anti-EV71 drug candidates with high anti-EV71 activity in cell-based assay and enhanced mouse plasma stability.

Fragment-wise design of inhibitors to 3C proteinase from enterovirus 71.

Background: Enterovirus 71 (EV71) is a causative agent of hand, foot and mouth disease (HFMD), which can spread its infection to central nervous and other systems with severe consequence. A key factor in the replication of EV71 is its 3C proteinase (3C(pro)), a significant drug target. Peptidomimetics were employed as inhibitors of this enzyme for developing antivirals.

Structure activity relationship of pyridoxazinone substituted RHS analogs of oxabicyclooctane-linked 1,5-naphthyridinyl novel bacterial topoisomerase inhibitors as broad-spectrum antibacterial agents (Part-6).

Oxabicyclooctane linked 1,5-naphthyridinyl-pyridoxazinones are novel broad-spectrum bacterial topoisomerase inhibitors (NBTIs) targeting bacterial DNA gyrase and topoisomerase IV at a site different than quinolones. Due to lack of cross-resistance to known antibiotics they present excellent opportunity to combat drug-resistant bacteria. A structure activity relationship of the pyridoxazinone moiety is described in this Letter.

Hydroxy tricyclic 1,5-naphthyridinone oxabicyclooctane-linked novel bacterial topoisomerase inhibitors as broad-spectrum antibacterial agents-SAR of RHS moiety (Part-3).

Novel bacterial topoisomerase inhibitors (NBTIs) are a new class of broad-spectrum antibacterial agents targeting bacterial Gyrase A and ParC and have potential utility in combating antibiotic resistance. (R)-Hydroxy-1,5-naphthyridinone left-hand side (LHS) oxabicyclooctane linked pyridoxazinone right-hand side (RHS) containing NBTIs showed a potent Gram-positive antibacterial profile. SAR around the RHS moiety, including substitutions around pyridooxazinone, pyridodioxane, and phenyl propenoids has been described.

Structure activity relationship of substituted 1,5-naphthyridine analogs of oxabicyclooctane-linked novel bacterial topoisomerase inhibitors as broad-spectrum antibacterial agents (Part-4).

Bacterial resistance is rapidly growing, necessitating the need to discover new agents. Novel bacterial topoisomerase inhibitors (NBTIs) are new class of broad-spectrum antibacterial agents targeting bacterial DNA gyrase and topoisomerase IV. This class of inhibitors binds to an alternative binding site relative to fluoroquinolones and shows no cross-resistance to quinolones.

Tricyclic 1,5-naphthyridinone oxabicyclooctane-linked novel bacterial topoisomerase inhibitors as broad-spectrum antibacterial agents-SAR of left-hand-side moiety (Part-2).

Novel bacterial topoisomerase inhibitors (NBTIs) represent a new class of broad-spectrum antibacterial agents targeting bacterial Gyrase A and ParC and have potential utility in combating antibiotic resistance. A series of novel oxabicyclooctane-linked NBTIs with new tricyclic-1,5-naphthyridinone left hand side moieties have been described. Compounds with a (R)-hydroxy-1,5-naphthyridinone moiety (7) showed potent antibacterial activity (e.

Structures of Enterovirus 71 3C proteinase (strain E2004104-TW-CDC) and its complex with rupintrivir.

The crystal structure of 3C proteinase (3C(pro)) from Enterovirus 71 (EV71) was determined in space group C2221 to 2.2 Å resolution. The fold was similar to that of 3C(pro) from other picornaviruses, but the difference in the β-ribbon reported in a previous structure was not observed.

Conformational plasticity of the 2A proteinase from enterovirus 71.

The 2A proteinase (2A(pro)) is an enterovirally encoded cysteine protease that plays essential roles in both the processing of viral precursor polyprotein and the hijacking of host cell translation and other processes in the virus life cycle. Crystallographic studies of 2A(pro) from enterovirus 71 (EV71) and its interaction with the substrate are reported here. EV71 2A(pro) was comprised of an N-terminal domain of a four-stranded antiparallel β sheet and a C-terminal domain of a six-stranded antiparallel β barrel with a tightly bound zinc atom.