RESUMO
Bicycles are constrained bicyclic peptides formed through reaction of three cysteine residues within a linear sequence with a trivalent, symmetrical small molecule scaffold. Bicycles with high binding affinities to therapeutically important targets can be discovered using screening technologies such as phage display. Increasing the chemical diversity of Bicycles should improve the probability of finding hits to new targets and can be achieved by expanding the toolbox of Bicycle forming chemistries. Gold(III) S-arylation has recently been described as a method for the efficient bioconjugation of cysteine residues under conditions compatible with phage display. Herein, we explore the scope and generality of this methodology for Bicycle construction through the synthesis and evaluation of four novel tris-Gold complexes. These new scaffolds were systematically reacted with a variety of peptide sequences, varying in amino acid loop lengths. All four scaffolds proved to be capable and selective reactive partners for each peptide sequence and afforded the desired Bicycle products in 13-48% isolated yield. This work exemplifies Gold-mediated arylation as a general approach for construction of novel, highly constrained Bicycles.
Assuntos
Cisteína , Ouro , Sequência de Aminoácidos , Ciclismo , Cisteína/química , Ouro/química , Biblioteca de Peptídeos , Peptídeos/químicaRESUMO
Growing antibiotic resistance is rapidly threatening the efficacy of treatments for Gram-negative infections. Bicycle molecules, constrained bicyclic peptides from diverse libraries generated by bacteriophage display that bind with high affinity to a chosen target are a potential new class of antibiotics. The generally impermeable bacterial outer membrane currently limits the access of peptides to bacteria. The conjugation of membrane active peptides offers an avenue for outer membrane penetration. Here, we investigate which physicochemical properties of a specific membrane active peptide (MAP), derived from ixosin-B, could be tweaked to enhance the penetration of conjugates by generating multiple MAP-Bicycle conjugate variants. We demonstrate that charge and hydrophobicity are important factors, which enhance penetration and, therefore, antimicrobial potency. Interestingly, we show that induction of secondary structure, but not a change in amphipathicity, is vital for effective penetration of the Gram-negative outer membrane. These results offer insights into the ways vectors could be designed to deliver Bicycle molecules (and other cargos) through biological membranes.
Assuntos
Antibacterianos , Antibacterianos/farmacologia , Antibacterianos/química , Interações Hidrofóbicas e Hidrofílicas , Testes de Sensibilidade Microbiana , Membrana Externa Bacteriana/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Peptídeos Cíclicos/farmacologia , Peptídeos Cíclicos/químicaRESUMO
Angiotensin-converting enzyme 2 (ACE2) is a metalloprotease that cleaves angiotensin II, a peptide substrate involved in the regulation of hypertension. Here, we identified a series of constrained bicyclic peptides, Bicycle, inhibitors of human ACE2 by panning highly diverse bacteriophage display libraries. These were used to generate X-ray crystal structures which were used to inform the design of additional Bicycles with increased affinity and inhibition of ACE2 enzymatic activity. This novel structural class of ACE2 inhibitors is among the most potent ACE2 inhibitors yet described in vitro, representing a valuable tool to further probe ACE2 function and for potential therapeutic utility.
Assuntos
Enzima de Conversão de Angiotensina 2 , Carboxipeptidases , Humanos , Carboxipeptidases/química , Peptidil Dipeptidase A , Ciclismo , Peptídeos/farmacologia , Angiotensina II , Fragmentos de PeptídeosRESUMO
Alk-2-enylstannanes with 4-, 5- and 6-alkoxy- or -hydroxy-substituents are transmetallated stereoselectively with tin(iv) halides to generate allyltin trihalides which react with aldehydes to give (Z)-alk-3-enols with useful levels of 1,5-, 1,6- and 1,7-stereocontrol. Alk-2-enylstannanes with a stereogenic centre bearing a hydroxy or alkoxy group at the 4-, 5- or 6-position, react with overall (Z)-1,5-, 1,6- and 1,7-syn-stereoselectivity with respect to the hydroxy and alkoxy substituents. The analogous reactions of alkoxy- and -hydroxyalk-2-enylstannanes with a methyl bearing stereogenic centre at the 4- or 5-position react with overall (Z)-1,5- and 1,6-anti-stereoselectivity with respect to the hydroxy and methyl substituents.
RESUMO
The Diels-Alder reactions of a series of silyloxydienes and silylated dienes with acyclic alpha,beta-unsaturated ketones and N-acyloxazolidinones have been investigated. The endo/exo stereochemical outcome is strongly influenced by the substitution pattern of the reactants. High exo selectivity was observed when the termini of the diene and the dienophile involved in the shorter of the forming bonds were both substituted, while the normal endo preference was found otherwise. The exo-selective asymmetric Diels-Alder reactions using Evans' oxazolidinone chiral auxiliary furnished a high level of pi-facial selectivity in the same sense as their well-documented endo-selective counterparts. Computational results for these Diels-Alder reactions were consistent with the experimental endo/exo selectivity in most cases. A twist-asynchronous model accounts for the geometries and energies of the computed transition structures.
Assuntos
Cicloexenos/síntese química , Cetonas/química , Oxazolidinonas/química , Polienos/química , Ciclização , Modelos Moleculares , Estereoisomerismo , TermodinâmicaRESUMO
Optimisation of urea (5), identified from high throughput screening and subsequent array chemistry, has resulted in the identification of pyridine carboxamide (33) which is a potent motilin receptor agonist possessing favourable physicochemical and ADME profiles. Compound (33) has demonstrated prokinetic-like activity both in vitro and in vivo in the rabbit and therefore represents a promising novel small molecule motilin receptor agonist for further evaluation as a gastroprokinetic agent.
Assuntos
Carbono/química , Piridinas/química , Receptores dos Hormônios Gastrointestinais/agonistas , Receptores de Neuropeptídeos/agonistas , Animais , Química Farmacêutica/métodos , Desenho de Fármacos , Gastrinas/química , Humanos , Concentração Inibidora 50 , Cinética , Modelos Químicos , Piridinas/síntese química , Piridinas/farmacologia , Coelhos , Ratos , Receptores dos Hormônios Gastrointestinais/química , Receptores de Neuropeptídeos/químicaRESUMO
Cyclophilin inhibition has been a target for the treatment of hepatitis C and other diseases, but the generation of potent, drug-like molecules through chemical synthesis has been challenging. In this study, a set of macrocyclic cyclophilin inhibitors was synthesized based on the core structure of the natural product sanglifehrin A. Initial compound optimization identified the valine-m-tyrosine-piperazic acid tripeptide (Val-m-Tyr-Pip) in the sanglifehrin core, stereocenters at C14 and C15, and the hydroxyl group of the m-tyrosine (m-Tyr) residue as key contributors to compound potency. Replacing the C18-C21 diene unit of sanglifehrin with a styryl group led to potent compounds that displayed a novel binding mode in which the styrene moiety engaged in a π-stacking interaction with Arg55 of cyclophilin A (Cyp A), and the m-Tyr residue was displaced into solvent. This observation allowed further simplifications of the scaffold to generate new lead compounds in the search for orally bioavailable cyclophilin inhibitors.
Assuntos
Ciclofilinas/antagonistas & inibidores , Células Cultivadas , Cromatografia Líquida , Cristalografia por Raios X , Descoberta de Drogas , Humanos , Ligação de Hidrogênio , Lactonas/química , Lactonas/farmacologia , Espectroscopia de Prótons por Ressonância Magnética , Espectrometria de Massas por Ionização por Electrospray , Compostos de Espiro/química , Compostos de Espiro/farmacologia , Relação Estrutura-Atividade , Ressonância de Plasmônio de Superfície , TermodinâmicaRESUMO
N-Tosyl-protected 3-hydroxypyrrolidines are prepared by reaction of dimethylsulfoxonium methylide with readily available epoxysulfonamides.
Assuntos
Amidas/química , Aziridinas/química , Compostos de Epóxi/química , Metanol/química , Pirrolidinas/química , Sulfóxidos/química , Enxofre/química , Cristalografia por Raios X , Hidroxilação , Modelos Moleculares , Estrutura Molecular , Pirrolidinas/síntese químicaRESUMO
[reaction: see text]. Regio- and stereodefined allylic N-sulfonylamines are synthesized in high yields and under experimentally straightforward conditions by reaction of N-sulfonylaziridines with excess dimethylsulfonium methylide.
RESUMO
N-(3-fluorophenyl)-1-[(4-([(3S)-3-methyl-1-piperazinyl]methyl)phenyl)acetyl]-4-piperidinamine 12 (GSK962040) is a novel small molecule motilin receptor agonist. It possesses excellent activity at the recombinant human motilin receptor and also at the native rabbit motilin receptor where its agonist activity results in potentiation of the amplitude of neuronal-mediated contractions of isolated gastric antrum tissue. Compound 12 also possesses highly promising pharmacokinetic profiles in both rat and dog, and these results, in combination with further profiling in human native tissue and an in vivo model of gastrointestinal transit in the rabbit, have led to its selection as a candidate for further development.
Assuntos
Descoberta de Drogas , Fármacos Gastrointestinais/farmacologia , Piperazinas/farmacologia , Piperidinas/farmacologia , Antro Pilórico/efeitos dos fármacos , Receptores dos Hormônios Gastrointestinais/agonistas , Receptores de Neuropeptídeos/agonistas , Animais , Cães , Motilidade Gastrointestinal/efeitos dos fármacos , Humanos , Contração Muscular/efeitos dos fármacos , Piperazinas/química , Piperidinas/química , Antro Pilórico/fisiologia , Coelhos , RatosRESUMO
The scope and limitations of lithium 2,2,6,6-tetramethylpiperidide (LTMP)-modified reductive alkylation of epoxides is detailed. A variety of organolithiums are added to terminal and 2,2-disubstituted epoxides in the presence of LTMP to generate alkenes in a completely regio- and highly stereoselective manner. Arylated alkenes, dienes, allylsilanes, and enynes are accessed using this procedure. The methodology is applied in the synthesis of the roller leaf moth pheromone, (3E,5Z)-dodecadienyl acetate. The corresponding reaction without LTMP has also been examined, and a study using deuterated epoxides provides insight into the mechanism. In the presence of LTMP, Grignard reagents are also shown to produce E-alkenes directly from epoxides.
Assuntos
Compostos de Epóxi/química , Compostos de Lítio/química , Piridinas/química , Acetatos/química , Alcenos/química , Amidas/química , Deutério/química , Dodecanol/análogos & derivados , Estrutura Molecular , Compostos Organometálicos , Atrativos Sexuais , Silanos/química , EstereoisomerismoRESUMO
E-Alkenes (including arylated alkenes, dienes, and allylsilanes) are efficiently prepared by alpha-deprotonation of terminal epoxides using lithium 2,2,6,6-tetramethylpiperidide, followed by in situ trapping with organolithiums or Grignard reagents.
RESUMO
Modification of the pyrimidone 5-substituent in clinical candidate SB-435495 has given a series of inhibitors of recombinant lipoprotein-associated phospholipase A(2) with sub-nanomolar potency. Cyclopentyl fused derivative 21, SB-480848, showed an enhanced in vitro and in vivo profile versus SB-435495 and has been selected for progression to man.
Assuntos
Inibidores Enzimáticos/farmacologia , Fosfolipases A/antagonistas & inibidores , Pirimidinonas/farmacologia , 1-Alquil-2-acetilglicerofosfocolina Esterase , Animais , Inibidores do Citocromo P-450 CYP2D6 , Inibidores Enzimáticos/química , Humanos , Técnicas In Vitro , Cinética , Fosfolipases A/sangue , Fosfolipases A2 , Pirimidinonas/química , Coelhos , Proteínas Recombinantes/antagonistas & inibidoresRESUMO
A series of 1-(biphenylmethylamidoalkyl)-pyrimidones has been designed as nanomolar inhibitors of recombinant lipoprotein-associated phospholipase A(2) with high potency in whole human plasma. 5-(Pyrazolylmethyl) derivative 16 and 5-(methoxypyrimidinylmethyl) derivative 27 demonstrated excellent pharmacodynamic profiles which correlated well with their pharmacokinetic effects.
Assuntos
Fosfolipases A/antagonistas & inibidores , Pirimidinonas/farmacocinética , 1-Alquil-2-acetilglicerofosfocolina Esterase , Administração Oral , Animais , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacocinética , Humanos , Concentração Inibidora 50 , Cinética , Pirimidinonas/síntese química , Pirimidinonas/química , Coelhos , Relação Estrutura-AtividadeRESUMO
The introduction of a functionalised amido substituent into a series of 1-(biphenylmethylacetamido)-pyrimidones has given a series of inhibitors of recombinant lipoprotein-associated phospholipase A(2) with sub-nanomolar potency and very encouraging developability properties. Diethylaminoethyl derivative 32, SB-435495, was selected for progression to man.