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The synthesis and structure-activity relationship (SAR) of novel and highly potent positive allosteric modulators of AMPA receptors, 3-biphenyl-4-yl-4-cyano-5-ethyl-1-methyl-1H-pyrrole-2-carboxylic acid, are described. These studies indicated that higher potency was achieved with ortho substitution of the distal (D) phenyl of the 3-biphenyl ring and resulted in the discovery of a potent pyrrole LY2059346 (23q), that was selected for further evaluation in in vitro native tissue assays and in vivo experiments.

The synthesis of (2Z,4RS)-5-acetamido-4-guanidino-2-benzamidopent-2-enoic acid (sodium salt) 5 is reported. Wittig–Horner olefination of diamino protected propionaldehyde 8 with phosphonoglycine trimethyl ester 11 provided (Z)-olefin methyl ester 12. The methyl ester was converted to allyl ester 15 by initial hydrolysis with lithium hydroxide followed by reaction with allyl bromide. Target compound 5 was prepared from allyl ester 15 by initial formation of bis(Boc)guanidino ester 16 followed by treatment with tetrakis(triphenylphosphine)palladium(0). The product was evaluated for activity against influenza neuraminidase and was found to be weakly active.

Entry of influenza virus into the host cell is dependent on the fusion of the viral envelope with the endosomal membrane and is mediated by a low-pH-induced change of the viral hemagglutinin (HA) to a conformation that is fusogenic. A compound related to podocarpic acid (180299) was identified that inhibits multicycle replication of influenza A/Kawasaki/86 (H1N1) virus in culture. Treatment of Madin-Darby canine kidney (MDCK) cells with 180299 at 1 h before infection resulted in the inhibition of viral protein synthesis. Addition of 20 microgram of 180299/ml at 1 h p.i. had no effect, indicating that 180299 affects an early step of the influenza viral replication cycle. Genetic analysis of reassortants between sensitive and resistant viruses demonstrated that hemagglutinin (HA) conferred the 180299-resistant (180299(r)) phenotype. Twelve independent isolates of influenza A/Kawasaki/86 were selected for resistance to 180299, and sequence analysis revealed that each of these viruses contained amino acid substitutions in the HA. These mutations are dispersed throughout the HA primary amino acid sequence and cluster in one of two regions: the interface between HA1 and HA2 and in a region near the fusion domain of HA2. When compared with the parent virus, the pH-of-inactivation of the resistant mutants was increased by 0.3 to 0.6 pH unit, suggesting that the mutant HAs undergo the conformational change at an elevated pH. Fusion of human erythrocytes to MDCK cells infected with parent influenza A/Kawasaki/86 was inhibited by 180299 (0.1-10 microgram/ml) in a concentration-dependent manner, whereas fusion of erythrocytes to MDCK cells infected with 180299(r) mutants was not affected. These results suggest that 180299 interacts with the neutral pH conformation of influenza A HA and prevents the low-pH-induced change of HA to its fusogenic conformation.

Novel noncoded D-amino acids have been combined with decahydroisoquinoline, octahydrothienopyridine, and urea hydroxyethylamine isosteres to provide potent HIV-1 protease inhibitors with excellent HIV-1 antiviral activity. LY314613 shows a promising combination of potency and oral bioavailability. Trends in the SAR and comparisons to other isostere derivatives will be discussed.

Using the hydroxyethylamine isosteres 1 and 2 containing the novel cis-octahydrothienopyridine moiety, substantial enhancement of binding potencies for HIV-1 protease inhibitors which incorporate carbamate linked heterocyclic P2 ligands has been realized. This increase in binding has led to a very potent antiviral compound (LY326188). The pharmacokinetics of selected derivatives are detailed in this report.

Replacement of the decahydroisoquinoline group contained in Ro 31-8959 by a cis -octahydrothienopyridine moiety has provided a high affinity hydroxyethylamine isostere for use in HIV-1 protease inhibitors. Further gains in potency have been realized by incorporation of a sulfur atom into the P 1 benzyl group. Modification by a key P 2 ligand provided LY316440, a potent, orally absorbed inhibitor of HIV-1 protease.

The synthesis and microbiological evaluation of a new series of 3-thiazol-4-yl-carba-1-dethiacephalosporins is described. Structure activity relationship was achieved by changing substitution at the 2-position of the thiazole moiety. The result was a marked variance of microbiological activity in the C7 side-chain derivatives. ATMO derivatives possess potent activity against both Gram-positive and Gram-negative bacteria. For example, MICs (microgram/ml) of LY215226 against representative organisms are as follows: S. aureus 0.25, S. pneumoniae 0.008, H. influenzae 0.008, E. coli 0.25, K. pneumoniae 0.008, E. cloacae 0.5, S. typhi 0.25, and M. morganii 0.25.

The synthesis and microbiological evaluation of a new series of 3-thiazol-4-yl-carba-1-dethiacephalosporins is described. Structure activity relationship was achieved by changing substitution at the 2-position of the thiazole moiety. The result was a marked variance of microbiological activity in the C7 side-chain derivatives. ATMO derivatives possess potent activity against both Gram-positive and Gram-negative bacteria. For example, MICs (microgram/ml) of LY215226 against representative organisms are as follows: S. aureus 0.25, S. pneumoniae 0.008, H. influenzae 0.008, E. coli 0.25, K. pneumoniae 0.008, E. cloacae 0.5, S. typhi 0.25, and M. morganii 0.25.

Using the hydroxyethylamine isosteres 1 and 2 containing the novel cis-octahydrothienopyridine moiety, substantial enhancement of binding potencies for HIV-1 protease inhibitors which incorporate carbamate linked heterocyclic P2 ligands has been realized. This increase in binding has led to a very potent antiviral compound (LY326188). The pharmacokinetics of selected derivatives are detailed in this report.

Replacement of the decahydroisoquinoline group contained in Ro 31-8959 by a cis -octahydrothienopyridine moiety has provided a high affinity hydroxyethylamine isostere for use in HIV-1 protease inhibitors. Further gains in potency have been realized by incorporation of a sulfur atom into the P 1 benzyl group. Modification by a key P 2 ligand provided LY316440, a potent, orally absorbed inhibitor of HIV-1 protease.

Novel noncoded D-amino acids have been combined with decahydroisoquinoline, octahydrothienopyridine, and urea hydroxyethylamine isosteres to provide potent HIV-1 protease inhibitors with excellent HIV-1 antiviral activity. LY314613 shows a promising combination of potency and oral bioavailability. Trends in the SAR and comparisons to other isostere derivatives will be discussed.

The enhanced stability of the carbacephem nucleus over the corresponding cephalosporin nucleus has allowed the synthesis of 7-arylglycyl-3-trifluoromethyl-carbacephems. These unique carbacephems possess broad spectrum activity and high stability to both plasmid and chromosomally mediated s-lactamases.

Bacterial peptidoglycan is composed of a network of beta-[1,4]-linked glyan strands that are cross-linked through pendant peptide chains. The final product, the murein sacculus, is a single, covalently closed macromolecule that precisely defines the size and shape of the bacterial cell. The recent increase in bacterial resistance to cell wall active agents has led to a resurgence of activity directed toward improving our understanding of the resistance mechanisms at the molecular level. The biosynthetic enzymes and their natural substrates can be invaluable tools in this endeavor. While modern experimental techniques have led to isolation and purification of the biosynthetic enzymes utilized in peptidoglycan biosynthesis, securing useful quantities of their requisite substrates from natural substrates has remained problematic. In an effort to address this issue, we report the first total synthesis of lipid II (4), the final monomeric intermediate utilized by Gram positive bacteria for peptidoglycan biosynthesis.

To increase subtype selectivity and provide a novel means to alter receptor function, we discovered and characterization potentiators for the metabotropic glutamate 2 receptor (mGlu2). A class of 3-pyridylmethylsulfonamides (e.g., 3-MPPTS; 2,2,2-trifluoro-N-[3-(2-methoxyphenoxy)phenyl]-N-(3-pyridinylmethyl)-ethanesulfonamide) were found to be potent, subtype-selective potentiators of human and rat mGlu2. The sulfonamides increased agonist potency in functional assays but did not displace orthosteric radiolabeled antagonist or agonist binding to cloned mGlu2 receptors. Rather, the modulators increased the affinity of most of the orthosteric agonists including glutamate, DCG-IV (2S,2′R,3′R)-2-(2′,3′-dicarboxylcyclopropyl)glycine), and LY354740 (1S,2S,5R,6S-2-aminobicyclo[3.1.0]hexane-2,6-bicaroxylate monohydrate). In striatal brain slices, LY354740 inhibited evoked excitatory postsynaptic potentials (EPSPs) equally well following either a low- (0.06 Hz) or high (4 Hz)-frequency stimulation of corticostriatal afferents. In contrast, the mGlu2 potentiator cyPPTS (2,2,2-trifluoro-N-[3-(cyclopentyloxy)phenyl]-N-(3-pyridinylmethyl)-ethanesulfonamide) inhibited striatal EPSPs only at higher frequencies of stimulation (2 and 4 Hz). Several sulfonamides including 4-MPPTS, 4-APPES (N-[4-(4-carboxamidophenoxy)phenyl]-N-(3-pyridinylmethyl)-ethanesulfonamide hydrochloride monohydrate) and/or CBiPES N-[4′-cyano-biphenyl-3-yl)-N-(3-pyridinylmethyl)-ethanesulfonamide hydrochloride) were tested in mGlu2/3 agonist-sensitive rodent model(s) of anxiety and psychosis. As seen with LY354740, both 4-MPPTS and 4-APPES were efficacious in a rat fear-potentiated startle paradigm. Likewise in mice, CBiPES attenuated a stress-induced hyperthermia and PCP-induced hyperlocomotor activity. Furthermore, CBiPES mediated alteration in PCP-induced hyperlocomotor activity was sensitive to mGlu2/3 antagonist pretreatment. Taken together, the data indicate mGlu2 receptor potentiators have a unique use-dependent effect on presynaptic glutamate release, and show efficacy in several mGlu2/3-sensitive animal models of psychiatric disorders.

Bacterial peptidoglycan is composed of a network of beta-[1,4]-linked glyan strands that are cross-linked through pendant peptide chains. The final product, the murein sacculus, is a single, covalently closed macromolecule that precisely defines the size and shape of the bacterial cell. The recent increase in bacterial resistance to cell wall active agents has led to a resurgence of activity directed toward improving our understanding of the resistance mechanisms at the molecular level. The biosynthetic enzymes and their natural substrates can be invaluable tools in this endeavor. While modern experimental techniques have led to isolation and purification of the biosynthetic enzymes utilized in peptidoglycan biosynthesis, securing useful quantities of their requisite substrates from natural substrates has remained problematic. In an effort to address this issue, we report the first total synthesis of lipid II (4), the final monomeric intermediate utilized by Gram positive bacteria for peptidoglycan biosynthesis.

[reaction: see text]. A synthesis of stereochemically pure and orthogonally protected N-acetyl-(2-deoxy-2-aminoglucopyranosyl)-beta-[1,4]-N-acetylmuramyl (NAG-NAM) monopeptide (2), the glycopeptide core of lipid II and of the bacterial cell wall repeating unit, is reported.

The enhanced stability of the carbacephem nucleus over the corresponding cephalosporin nucleus has allowed the synthesis of 7-arylglycyl-3-trifluoromethyl-carbacephems. These unique carbacephems possess broad spectrum activity and high stability to both plasmid and chromosomally mediated s-lactamases.

Computational chemistry made possible the prediction of the three-dimensional structures of γ-lactam analogues of penems and carbapenems before the analogues were made. Molecular superpositioning showed that these novel structures with a 7β-acylamino side-chain present the pharmacophoric groups in close spatial similarity to the groups in biologically active cephalosporin and penicillin antibiotics. This suggests that 8-oxo-7-acylamino-1-azabicyclo[3.3.0]-oct-2-ene-2-carboxylates and the 4-thia-analogues can be accommodated in the same active sites of essential bacterial penicillin-binding proteins where cephalosporins and penicillins are recognized. The syntheses of these compounds are reported. The γ-lactams exhibit low, but detectable levels of antibacterial activity and suggest promise that substantial activity can be achieved with other γ-lactams.

γ-Lactam analogues of carbapenems have been synthesized using a [3+2] cyclization approach. Slight antibiotic activity was observed in one case.

We report the selection and characterization of influenza A/NWS-G70c and B/HK/8/73 (HG) viruses which are resistant to the potent influenza neuraminidase inhibitor, 4-guanidino-Neu5Ac2en. Viruses were selected which replicated in MDCK cells in the presence of 20 micrograms/ml inhibitor. The neuraminidase of resistant viruses was > 200-fold more resistant to 4-guanidino-Neu5Ac2en than was the neuraminidase of the parent viruses. Although amounts of neuraminidase protein were similar in resistant and parent viruses, the enzyme activity of the resistant neuraminidase heads was reduced by > 95% for the substrates used. Relative to parent viruses, the resistant viruses replicated to equal or greater titers in tissue culture and in embryonated chicken eggs. Sequence analysis revealed a single nucleotide mutation in the neuraminidase gene of each virus resulting in the change of the conserved Glu 119 (which lies in a pocket beneath the active site of the enzyme) to Gly thus eliminating an electrostatic interaction with the C-4 guanidinium moiety of the inhibitor. Mutations (Asn-->Ser) at amino acids 145 and 150 were also found in the hemagglutinin gene of the B/HK/8/73 (HG) virus resistant to 4-guanidino-Neu5Ac2en. No changes were found in the hemagglutinin gene of the resistant A/NWS-G70c virus.

Obtention de phenoxyacetamido-7 carbacepheme-3- et cepheme-3 carboxylates-4 et de phenoxyacetamido-7 carbacepheme-3 dicarboxylates-3,4