RESUMO
Using the newly introduced designer surfactant polyethyleneglycol ubiquinol sebacate (PQS), as the platform for micellar catalysis, nonracemic BINAP has been covalently attached and rhodium(I) inserted to form PQS-BINAP-Rh. This species, the first example of a nonracemically-ligated transition metal catalyst-tethered amphiphile, can be utilized for Rh-catalyzed asymmetric conjugate addition reactions of arylboronic acids to acyclic and cyclic enones. These are performed in water at room temperature, while the catalyst can be recycled without its removal from water in the reaction vessel.
RESUMO
A series of 5-aryl-2-amino-imidazothiadiazole (ITD) derivatives were identified by a phenotype-based high-throughput screening using a blood stage Plasmodium falciparum (Pf) growth inhibition assay. A lead optimization program focused on improving antiplasmodium potency, selectivity against human kinases, and absorption, distribution, metabolism, excretion, and toxicity properties and extended pharmacological profiles culminated in the identification of INE963 (1), which demonstrates potent cellular activity against Pf 3D7 (EC50 = 0.006 µM) and achieves "artemisinin-like" kill kinetics in vitro with a parasite clearance time of <24 h. A single dose of 30 mg/kg is fully curative in the Pf-humanized severe combined immunodeficient mouse model. INE963 (1) also exhibits a high barrier to resistance in drug selection studies and a long half-life (T1/2) across species. These properties suggest the significant potential for INE963 (1) to provide a curative therapy for uncomplicated malaria with short dosing regimens. For these reasons, INE963 (1) was progressed through GLP toxicology studies and is now undergoing Ph1 clinical trials.
Assuntos
Antimaláricos , Antagonistas do Ácido Fólico , Malária Falciparum , Malária , Animais , Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Antagonistas do Ácido Fólico/uso terapêutico , Malária/tratamento farmacológico , Malária Falciparum/tratamento farmacológico , Camundongos , Camundongos SCID , Plasmodium falciparumRESUMO
A new strategy for the synthesis of chiral ß-alkynyl esters which relies on sequential Pd and Cu catalysis is reported. Terminal alkynes bearing aryl, alkyl, and silyl groups can be employed without prior activation yielding a wide range of important chiral building blocks. The reaction sequence utilizes a robust Pd(II)-catalyzed hydroalkynylation of ynoates with terminal alkynes providing geometrically pure ynenoates which are readily reduced by CuH. In contrast to previous reports, where additions to ynenoates proceed with marginal preference for the 1,6-pathway, this conjugate reduction occurs with high 1,4-selectivity yielding ß-alkynyl esters with excellent levels of enantioselectivity. Importantly, the method tolerates a wide range of functionality, including allylic carbonates and carbamates, and thus allows for rapid elaboration of the ß-alkynyl esters into a variety of chiral, substituted heterocycles.
Assuntos
Alcinos/química , Cobre/química , Ésteres/química , Ésteres/síntese química , Paládio/química , Alcinos/síntese química , Catálise , Estrutura Molecular , EstereoisomerismoRESUMO
The remarkable effects of added salts on the properties of aqueous micelles derived from the amphiphile PTS are described. Most notably, Heck reactions run in the presence of NaCl lead to couplings on aryl bromides in water at room temperature. Olefin cross- and ring-closing metathesis reactions run in the presence of small amounts of pH-lowering KHSO(4) are also accelerated, another phenomenon that does not apply to typical processes in organic media. These salt effects allow, in general, for synthetically valuable C-C bond-forming processes to be conducted under environmentally benign conditions. Recycling of the surfactant is also demonstrated.
Assuntos
Micelas , Paládio/química , Alcenos/química , Catálise , Microscopia Eletrônica de Transmissão , Estrutura Molecular , Temperatura , Água/químicaRESUMO
The synthesis of the pentacylic core of (+)-citrinadin A is described. Our strategy harnesses the power of palladium-catalyzed trimethylenemethane chemistry (Pd-TMM) to form the key spirooxindole motif in a catalytic, asymmetric fashion. Upon the conversion of this spirooxindole to a vinyl epoxide electrophile, the piperidine ring is directly added via a diastereoselective metalation followed by an SN2' addition. The final ring of the pentacyclic core is then formed through an intramolecular SN2 displacement of the resulting activated alcohol.
RESUMO
Direct pharmacological inhibition of RAS has remained elusive, and efforts to target CRAF have been challenging due to the complex nature of RAF signaling, downstream of activated RAS, and the poor overall kinase selectivity of putative RAF inhibitors. Herein, we describe 15 (LXH254, Aversa, R.; et al. Int. Patent WO2014151616A1, 2014), a selective B/C RAF inhibitor, which was developed by focusing on drug-like properties and selectivity. Our previous tool compound, 3 (RAF709; Nishiguchi, G. A.; et al. J. Med. Chem. 2017, 60, 4969), was potent, selective, efficacious, and well tolerated in preclinical models, but the high human intrinsic clearance precluded further development and prompted further investigation of close analogues. A structure-based approach led to a pyridine series with an alcohol side chain that could interact with the DFG loop and significantly improved cell potency. Further mitigation of human intrinsic clearance and time-dependent inhibition led to the discovery of 15. Due to its excellent properties, it was progressed through toxicology studies and is being tested in phase 1 clinical trials.
Assuntos
Antineoplásicos/química , Descoberta de Drogas/métodos , Mutação/genética , Inibidores de Proteínas Quinases/química , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Proteínas Proto-Oncogênicas B-raf/genética , Animais , Antineoplásicos/farmacologia , Desenho de Fármacos , Descoberta de Drogas/tendências , Humanos , Simulação de Acoplamento Molecular/métodos , Simulação de Acoplamento Molecular/tendências , Mutação/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto/métodosRESUMO
A nonionic amphiphile such as Triton X-100 or the vitamin E-based PTS, both of which form nanomicelles in water, promotes Heck cross-couplings of non-water-soluble partners at ambient temperatures. These are the first examples of Heck reactions conducted in water (as the only solvent) at room temperature.
RESUMO
Copper impregnated into charcoal efficiently catalyzes cross-couplings between aryl bromides and phenols. The etherifications were conveniently promoted by microwave heating. [structure: see text]
RESUMO
RAS oncogenes have been implicated in >30% of human cancers, all representing high unmet medical need. The exquisite dependency on CRAF kinase in KRAS mutant tumors has been established in genetically engineered mouse models and human tumor cells. To date, many small molecule approaches are under investigation to target CRAF, yet kinase-selective and cellular potent inhibitors remain challenging to identify. Herein, we describe 14 (RAF709) [ Aversa , Biaryl amide compounds as kinase inhibitors and their preparation . WO 2014151616, 2014 ], a selective B/C RAF inhibitor, which was developed through a hypothesis-driven approach focusing on drug-like properties. A key challenge encountered in the medicinal chemistry campaign was maintaining a balance between good solubility and potent cellular activity (suppression of pMEK and proliferation) in KRAS mutant tumor cell lines. We investigated the small molecule crystal structure of lead molecule 7 and hypothesized that disruption of the crystal packing would improve solubility, which led to a change from N-methylpyridone to a tetrahydropyranyl oxy-pyridine derivative. 14 proved to be soluble, kinase selective, and efficacious in a KRAS mutant xenograft model.
Assuntos
2,2'-Dipiridil/análogos & derivados , Antineoplásicos/farmacologia , Benzamidas/farmacologia , Quinases raf/antagonistas & inibidores , Proteínas ras/genética , 2,2'-Dipiridil/química , 2,2'-Dipiridil/farmacologia , Animais , Antineoplásicos/química , Antineoplásicos/farmacocinética , Benzamidas/química , Cristalografia por Raios X , Cães , Desenho de Fármacos , Descoberta de Drogas , Estabilidade de Medicamentos , Humanos , Concentração Inibidora 50 , Camundongos , Terapia de Alvo Molecular , Neoplasias/tratamento farmacológico , Neoplasias/genética , Proteínas Proto-Oncogênicas B-raf/química , Proteínas Proto-Oncogênicas p21(ras)/genética , Ratos , Relação Estrutura-Atividade , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
[reaction: see text] CuH-catalyzed asymmetric conjugate reduction of beta-silyl-alpha,beta-unsaturated esters has been developed. Using PMHS as a stoichiometric source of hydride and in situ generated CuH ligated by Solvias' JOSIPHOS analogue PPF-P(t-Bu)(2) leads to highly enantioselective 1,4-reductions.
RESUMO
We present a full account detailing the development of a sequential catalysis strategy for the synthesis of chiral ß-alkynyl carbonyl and sulfonyl derivatives. A palladium-catalyzed cross coupling of terminal alkyne donors with acetylenic ester, ketone, and sulfone acceptors generates stereodefined enynes in high yield. These compounds are engaged in an unprecedented, regio- and enantioselective copper-catalyzed conjugate reduction. The process exhibits a high functional group tolerance, and this enables the synthesis of a broad range of chiral products from simple, readily available alkyne precursors. The utility of the method is demonstrated through the elaboration of the chiral ß-alkynyl products into a variety of different molecular scaffolds. Its value in complex molecule synthesis is further validated through a concise, enantioselective synthesis of AMG 837, a potent GPR40 receptor agonist.
RESUMO
Palladium-catalysed cross-couplings, in particular Heck, Suzuki-Miyaura and Negishi reactions developed over three decades ago, are routinely carried out in organic solvents. However, alternative media are currently of considerable interest given an increasing emphasis on making organic processes 'greener'; for example, by minimising organic waste in the form of organic solvents. Water is the obvious leading candidate in this regard. Hence, this review focuses on the application of micellar catalysis, in which a 'designer' surfactant enables these award-winning coupling reactions to be run in water at room temperature.
RESUMO
The combination of catalytic amounts of [(R)-DTBM-SEGPHOS]CuH in the presence of stoichiometric DEMS (diethoxymethylsilane) in toluene at room temperature leads to asymmetric reductions of 4-substituted coumarins. Several targets or their known precursors can be prepared in high yields and ee's, including the muscarine receptor antagonist (R)-tolterodine.
Assuntos
Compostos Benzidrílicos/síntese química , Cumarínicos/química , Cresóis/síntese química , Fenilpropanolamina/síntese química , Compostos Benzidrílicos/química , Compostos Benzidrílicos/farmacologia , Catálise , Cumarínicos/síntese química , Cumarínicos/farmacologia , Cresóis/química , Cresóis/farmacologia , Ciclização , Oxirredução , Fenilpropanolamina/química , Fenilpropanolamina/farmacologia , Receptores Acoplados a Proteínas G/agonistas , Estereoisomerismo , Tartarato de TolterodinaRESUMO
A new heterogeneous catalyst composed of copper and nickel oxide particles supported within charcoal has been developed. It catalyzes cross-couplings that traditionally use palladium, nickel, or copper, including Suzuki-Miyaura reactions, Buchwald-Hartwig aminations, vinylalane alkylations, etherifications of aryl halides, aryl halide reductions, asymmetric conjugate reductions of activated olefins, and azide-alkyne "click" reactions.
Assuntos
Carvão Vegetal/química , Cobre/química , Níquel/química , CatáliseRESUMO
A study involving the relatively rare combination of heterogeneous catalysis conducted under microwave conditions is presented. Carbon-carbon bond formation, including Negishi and Suzuki couplings, can be quickly effected with aryl chloride partners by using a base metal (nickel) adsorbed in the pores of activated charcoal. Aminations were also studied, along with cross-couplings of vinyl alanes with benzylic chlorides as a means to stereodefined allylated aromatics. Reaction times for all these processes are typically reduced from several hours to minutes in a microwave reactor.
Assuntos
Carvão Vegetal/química , Química Farmacêutica/métodos , Micro-Ondas , Níquel/química , Tecnologia Farmacêutica/métodos , Carbono/química , Catálise , Química Farmacêutica/instrumentação , Cloretos/química , Espectroscopia de Ressonância Magnética , Metais/química , Modelos Químicos , Espectroscopia de Infravermelho com Transformada de Fourier , Tecnologia Farmacêutica/instrumentação , Temperatura , UltrassomRESUMO
Complexing catalytic amounts of CuH with a nonracemic JOSIPHOS or SEGPHOS ligand, together with stoichiometric PMHS, leads to exceedingly efficient and highly enantioselective 1,4-reductions of beta,beta-disubstituted enoates and lactones. An unprecedented substrate-to-ligand ratio of 7700:1 for this type of reaction is documented.