RESUMO
The development of simplified synthetic strategy to create structurally and functionally diverse pseudo-natural macrocyclic molecules is highly appealing but poses a marked challenge. Inspired by natural scaffolds, herein, we describe a practical and concise ligand-enabled Pd(II)-catalysed sp3 CâH alkylation, olefination and arylation macrocyclization, which could offer a novel set of pseudo-natural macrocyclic sulfonamides. Interestingly, the potential of ligand acceleration in CâH activation is also demonstrated by an unprecedented enantioselective sp3 CâH alkylation macrocyclization. Moreover, a combination of in silico screening and biological evaluation led to the identification of a novel spiro-grafted macrocyclic sulfonamide 2a, which showed a promising efficacy for the treatment of Parkinson's disease (PD) in a mouse model through the activation of silent information regulator sirtuin 3 (SIRT3).
RESUMO
A convenient strategy for the diastereoselective synthesis of α,ß-diamino diacid derivatives bearing congested vicinal acyclic tetrasubstituted stereocenters via catalytic Mannich-type reactions of azlactones and 2-aminoacrylates was established. A diverse set of α,ß-diamino diacid derivatives were synthesized in good to excellent yields and diastereoselectivities. Good enantioselectivity (up to 98:2 er) was achieved by employing the catalyst (DHQD)2PHAL in the subsequent asymmetric study.
Assuntos
Estereoisomerismo , CatáliseRESUMO
We report the direct asymmetric synthesis of pyrimido[2,1-b]benzothiazoles using a commercially available chiral amine catalyst. A variety of 2-benzothiazolimines and aldehydes were well tolerated under the reaction conditions and generated the corresponding products in 81-99% yields with excellent diastereoselectivities and enantioselectivities (up to >20:1 dr, 99% ee). Furthermore, the products could be easily converted to other useful chiral building blocks.
RESUMO
The catalytic asymmetric Mannich-type reaction of 3-hydroxy/3-aminooxindoles with 2-aminoacrylates to afford oxindole-derived acyclic amino acid derivatives bearing vicinal tetrasubstituted stereocenters is reported. (DHQ)2PHAL (4g) and quinine-derived squaramide (4d) were identified as efficient catalysts. Transformations of the Mannich-type reaction products highlight the utility of this synthetic strategy.
RESUMO
Psoriasis is a common immune-mediated skin disorder manifesting in abnormal skin plaques, and phosphodiesterase 4 (PDE4) is an effective target for the treatment of inflammatory diseases such as psoriasis. Toddacoumalone is a natural PDE4 inhibitor with moderate potency and imperfect drug-like properties. To discover novel and potent PDE4 inhibitors with considerable druggability, a series of toddacoumalone derivatives were designed and synthesized, leading to the compound (2R,4S)-6-ethyl-2-(2-hydroxyethyl)-2,8-dimethyl-4-(2-methylprop-1-en-1-yl)-2,3,4,6-tetrahydro-5H-pyrano[3,2-c][1,8]naphthyridin-5-one (33a) with high inhibitory potency (IC50 = 3.1 nM), satisfactory selectivity, favorable skin permeability, and a well-characterized binding mechanism. Encouragingly, topical administration of 33a exhibited remarkable therapeutic effects in an imiquimod-induced psoriasis mouse model.
Assuntos
Inibidores da Fosfodiesterase 4 , Psoríase , Administração Tópica , Animais , Nucleotídeo Cíclico Fosfodiesterase do Tipo 4/metabolismo , Camundongos , Inibidores da Fosfodiesterase 4/farmacologia , Inibidores da Fosfodiesterase 4/uso terapêutico , Psoríase/induzido quimicamente , Psoríase/tratamento farmacológico , PeleRESUMO
Phosphodiesterase-4 (PDE4) is an important drug target for inflammatory diseases. Previously, we identified a series of novel PDE4 inhibitors derived from the natural Toddacoumalone, among which the hit compound 2 with a naphthyridine scaffold showed moderate potency with the IC50 value of 400 nM. Based on the co-crystal structure of PDE4D-2, further structural optimizations and structure-activity relationship studies led to a highly potent PDE4 inhibitor 23a with the IC50 value of 0.25 nM and excellent selectivity profiles over other PDEs (>4000-fold). The co-crystal structure of PDE4D-23a elucidated that 23a has strong interactions with the M and Q pocket of PDE4D. Importantly, compound 23a significantly inhibits the release of inflammatory cytokines TNF-α and IL-6 in lipopolysaccharide-stimulated RAW264.7 cells. Thus, compound 23a with a naphthyridine scaffold is a promising PDE4 inhibitor for the treatment of inflammatory diseases.
Assuntos
Inibidores da Fosfodiesterase 4 , Anti-Inflamatórios/farmacologia , Nucleotídeo Cíclico Fosfodiesterase do Tipo 4 , Lipopolissacarídeos/farmacologia , Naftiridinas/farmacologia , Inibidores da Fosfodiesterase 4/química , Inibidores da Fosfodiesterase 4/farmacologia , Fator de Necrose Tumoral alfaRESUMO
Chemical modification of a specific amino acid residue on peptides represents an efficient strategy to improve their pharmacokinetics and facilitates the potential to achieve post-synthetic diversification of peptides. Herein, we reported the first Pd-catalyzed late-stage ortho-olefination of Tyr residues on peptides with high chemo- and site-selectivity, by employing the easily attached and removable silanol as a bifunctional protecting group and directing group. Up to hexapeptides with variation on amino acid sequences or locations of the Tyr residue and different olefins were compatible with this protocol, which enriched the chemical toolbox for late-stage modification via C(sp2)-H functionalization. Furthermore, the orthogonal protection strategies of Tyr were also developed and could be applied to SPPS.
RESUMO
We describe herein the first asymmetric total synthesis and biological evaluation of the natural PDE4 inhibitor toddacoumalone and its stereoisomers. The key step of the total synthesis is a formal asymmetric [4 + 2] cycloaddition reaction catalyzed by chiral secondary amine catalysts. A variety of pyranoquinolinones and 3-methylcrotonaldehyde are well tolerated under the optimized reaction conditions, which paved the way for further SAR studies. Further biological evaluation showed 1a' with the best PDE4 inhibitory activity (IC50 = 0.18 µM).
Assuntos
Produtos Biológicos/farmacologia , Cumarínicos/farmacologia , Nucleotídeo Cíclico Fosfodiesterase do Tipo 4/metabolismo , Inibidores da Fosfodiesterase 4/farmacologia , Produtos Biológicos/síntese química , Produtos Biológicos/química , Cumarínicos/síntese química , Cumarínicos/química , Reação de Cicloadição , Humanos , Estrutura Molecular , Inibidores da Fosfodiesterase 4/síntese química , Inibidores da Fosfodiesterase 4/química , EstereoisomerismoRESUMO
We report the first highly enantio- and diastereoselective three-component Povarov reaction between anilines and aldehydes catalyzed by a chiral amine catalyst. A wide variety of substituted tetrahydroquinolines were obtained with moderate to good yields and excellent enantioselectivity and diastereoselectivity (up to 99% ee and >95:5 dr) under the reaction conditions. Furthermore, the reaction intermediates could be efficiently converted to other valuable building blocks.