Koi Michele Morris

Design and synthesis of aminohydantoins as potent and selective human β-secretase (BACE1) inhibitors with enhanced brain permeability.

The identification of small molecule aminohydantoins as potent and selective human β-secretase inhibitors is reported. These analogs exhibit good brain permeability (40-70%), low nanomolar potency for BACE1, and demonstrate >100-fold selectivity for the structurally related aspartyl proteases cathepsin D, renin and pepsin. Alkyl and alkoxy groups at the meta-position of the P1 phenyl, which extend toward the S3 region of the enzyme, have contributed to the ligands reduced affinity for the efflux transporter protein P-gp, and decreased topological polar surface area, thus resulting in enhanced brain permeability. A fluorine substitution at the para-position of the P1 phenyl has contributed to 100-fold decrease of CYP3A4 inhibition and enhancement of compound metabolic stability. The plasma and brain protein binding properties of these new analogs are affected by substitutions at the P1 phenyl moiety. Higher compound protein binding was observed in the brain than in the plasma. Two structurally diverse potent BACE1 inhibitors (84 and 89) reduced 30% plasma Aβ40 in the Tg2576 mice in vivo model at 30 mg/kg p.o..

Naphthyl tetronic acids as multi-target inhibitors of bacterial peptidoglycan biosynthesis.

Since the discovery of penicillin in 1929, many important antibiotic agents have made significant contributions to the prevention and treatment of infections caused by bacteria. Despite these remarkable achievements, infections are still the second-leading cause of death worldwide and remain a major public health problem. Clearly, there is great need for novel antibacterial agents to address resistance problems associated with current antibiotics. Toward this end, three broad strategies have been recently employed in the search for new leads: high-throughput screening of large compound libraries, genomics, and combinatorial biosynthesis. Although some limitations of the former approach to targets in bacterial peptidoglycan biosynthesis have been reported, the peptidoglycan biosynthetic pathway remains an attractive target, validated in the clinic with fosfomycin and vancomycin. Peptidoglycan biosynthesis is a complex process, which involves three main stages: a) cytoplasmic soluble enzymes that include MurA–F, b) membrane-bound enzymes that include MraY and MurG, and finally c) transglycosylases and transpeptidases, which act external to the cytoplasmic membrane. The Mur enzymes are unique to bacteria and are involved in essential functions of both Gram-positive and Gram-negative organisms. Another attractive aspect of Mur enzyme inhibitors is the potential to be bactericidal, leading to cell lysis and bacterial death. Inhibitors of peptidoglycan biosynthesis initiate a complex process of gene expression resulting in the induction of MurA and Mur I in Gram-positive bacteria to compensate for the slower rate of peptidoglycan biosynthesis. Several classes of natural products or their semisynthetic derivatives represented by liposidomycins, amphomycins, and muraymycins are inhibitors of MraY, whereas nisin, ramoplanin, and mersacidin are lipid II inhibitors. In the last decade a few small-molecule inhibitors of the Mur enzymes have been reported, including sesquiterpene lactones, 5-sulfonoxyanthranilic acids T6361 and T6362, UDP-MurNAc (MurA), imidazolinones, 4-thiazolidinones, thienopyrazoles, phosphinates (MurB), peptidosulfonamides, 3-cyanothiophenes (MurF), and d-glutamic acid analogues (Mur I). Despite the discovery of small-molecule inhibitors of various Mur enzymes, many limitations have been noted, including poor antibacterial activities in cells. In parallel, a number of new assay formats for the identification of Mur enzyme inhibitors have been described based on different platforms such as ultra-efficient affinity HTS, LC– MS, TLC, HPLC, and solid-support TLC. Our efforts in identifying Mur enzyme inhibitors were based on an initial pathway screen searching for inhibitors of multiple enzymes, MurA–F. Hits in this assay were evaluated against the individual Mur enzymes for lead optimization. Using this strategy, we identified two classes of inhibitors : 3,5-dioxopyrazolidines and pulvinones, with activities against several of the Mur enzymes. Inhibitors of multiple Mur enzymes are attractive given the essential role of each Mur enzyme in peptidoglycan biosynthesis. This strategy may prevent the development of drug resistance through the multi-target hypothesis. Herein we report on the SAR of the naphthyl tetronic acids and highlight their binding to the E. coli enzyme MurB. The target naphthylfuran-2-ones 5a–k were prepared by a three-step process starting from 3-bromo-4-methoxy-5H-furan2-one (1) and the appropriately substituted aldehydes 2 (Scheme 1). Bromofuranone 1 was acquired by bromination of the commercially available 4-methoxy-5H-furan-2-one with Nbromosuccinimide in carbon tetrachloride at reflux. Deprotonation of 2 at C5 with lithium isopropylcyclohexylamide (LICA) followed by an aldol reaction with substituted aldehydes 2 mediated by anhydrous ZnCl2 afforded diastereomeric alcohols, which were converted into their mesylate or chloride derivatives in situ followed by elimination to generate the exocyclic double bond of 3 in the thermodynamically more stable Z configuration. The key step involved a Suzuki cross-coupling of 3 with aryl boronic acids catalyzed by either [PdACHTUNGTRENNUNG(PPh3)4] or [PdCl2ACHTUNGTRENNUNG(dppf)2] to afford the methoxyfuranones 4a–k. Demethylation of methoxyfuranones 4a–k with lithium bromide in the final step afforded the desired naphthylfuran-2ones 5a–k. Purification by silica gel column chromatography was followed by an acid wash of the collected fractions to restore the acidic functionality. A panel of nine enzymes was used to assess the abilities of the naphthylfuranones to inhibit the Mur enzymes, and thus to define SAR trends for multiple enzyme inhibition (Table 1). The four isomeric bis-naphthyl compounds (Entries 1–4) were evaluated to determine whether there is a preference for aor blinked naphthyl groups at either C3 or C5. The trend seems to favor C3 b and C5 a substitution. Replacement of naphthyl with p-chlorophenyl (Entries 5–8) gave compounds 5e–h with good broad-spectrum activity against the Mur enzymes, thus confirming the desired SAR trend. Further optimization of the C5 a methylidene naphthyl derivative 5h by changing the p[a] Dr. T. S. Mansour, Dr. B. Rasmussen, Dr. G. Krishnamurthy, C. Smeltzer, Dr. Y. Yang, Dr. A. Severin, P. J. Petersen, Dr. G. Singh Medicinal Chemistry, Wyeth Research 401 North Middletown Road, Pearl River, NY 10965 (USA) Fax: (+1)845-602-5580 E-mail : mansout@wyeth.com [b] Dr. C. E. Caufield, K. M. Morris, S. Naughton, S. Antane, Dr. D. Quagliato Wyeth Research, CN 8000, Princeton, NJ 08543 (USA) [c] Dr. R. Chopra, K. Svenson, Dr. J. Bard Wyeth Research, Cambridge, MA 02140 (USA)

Synthesis and structure―activity relationship of a novel series of heterocyclic sulfonamide γ-secretase inhibitors

gamma-Secretase inhibitors have been shown to reduce the production of beta-amyloid, a component of the plaques that are found in brains of patients with Alzheimers disease. A novel series of heterocyclic sulfonamide gamma-secretase inhibitors that reduce beta-amyloid levels in cells is reported. Several examples of compounds within this series demonstrate a higher propensity to inhibit the processing of amyloid precursor protein compared to Notch, an alternative gamma-secretase substrate.