RESUMO
Heteroarylation of alkenes with aryl iodides was efficiently achieved with a (MeDalphos)AuCl complex through AuI /AuIII catalysis. The possibility to combine oxidative addition of aryl iodides and π-activation of alkenes at gold is demonstrated for the first time. The reaction is robust and general (>30 examples including internal alkenes, 5-, 6-, and 7-membered rings). It is regioselective and leads exclusively to trans addition products. The (P,N) gold complex is most efficient with electron-rich aryl substrates, which are troublesome with alternative photoredox/oxidative approaches. In addition, it provides a very unusual switch in regioselectivity from 5-exo to 6-endo cyclization between the Z and E isomers of internal alkenols.
RESUMO
A new family of 2-hydroxyalk(en/yn)ylimidazoles has been evaluated as serine-histidine bare dyad models for the ring-opening reaction of L-lacOCA, a cyclic O-carboxyanhydride. These models were selected to unravel the implication of intramolecular hydrogen bonding and to substantiate its influence on the nucleophilicity of the alcohol moiety, as it is suspected to occur in enzyme active sites. Although designed to exclusively facilitate the preliminary step of proton transfer during the studied ring-opening reaction, these minimalistic models depicted a measureable increase in reactivity relative to the isolated fragments. A couple of reliable experimental and theoretical methods have been developed to readily monitor the strength of the intramolecular hydrogen bond in dilute solution. Results show that the folded conformers are the most nucleophilic species because of the intramolecular hydrogen bond.
Assuntos
Histidina/química , Serina/química , Acilação , Ligação de Hidrogênio , Imidazóis/síntese química , Imidazóis/química , Prótons , TermodinâmicaRESUMO
A well-defined poly(ethylene glycol) methyl ether-b-poly(lactic acid) copolymer (mPEG-PLA) featuring a new, Y-shaped, architecture with a hydroxyl functional group between the two blocks has been prepared and thoroughly characterized. The functional copolymer was then readily coupled to diglycolyl-cabazitaxel. The resulting copolymer conjugates assembled into stable and monodisperse nanoparticles (NPs) in aqueous suspension. The architecture of the copolymer conjugate is shown to impact the spatial distribution of the drug within the nanoparticles. With the Y-shaped architecture, cabazitaxel was found localized at the interface of the hydrophobic PLA core and the hydrophilic mPEG corona of the NPs, as substantiated by variable temperature NMR analysis of the nanoparticles in D2O. Preliminary in vitro release studies reveal dependence on the architecture of the copolymer conjugate. This new approach offers promising perspectives to finely tune the position of the active ingredient in polymeric nanoparticles.
Assuntos
Portadores de Fármacos , Nanopartículas/química , Poliésteres/química , Polietilenoglicóis/química , Taxoides/química , Materiais Biocompatíveis/química , Interações Hidrofóbicas e Hidrofílicas , Teste de Materiais , Polímeros/síntese química , Polímeros/química , Polímeros/metabolismoRESUMO
While blocking the renin angiotensin aldosterone system (RAAS) has been the main therapeutic strategy to control diabetic kidney disease (DKD) for many years, 25-30% of diabetic patients still develop the disease. In the present work we adopted a systems biology strategy to analyze glomerular protein signatures to identify drugs with potential therapeutic properties in DKD acting through a RAAS-independent mechanism. Glomeruli were isolated from wild type and type 1 diabetic (Ins2Akita) mice treated or not with the angiotensin-converting enzyme inhibitor (ACEi) ramipril. Ramipril efficiently reduced the urinary albumin/creatine ratio (ACR) of Ins2Akita mice without modifying DKD-associated renal-injuries. Large scale quantitative proteomics was used to identify the DKD-associated glomerular proteins (DKD-GPs) that were ramipril-insensitive (RI-DKD-GPs). The raw data are publicly available via ProteomeXchange with identifier PXD018728. We then applied an in silico drug repurposing approach using a pattern-matching algorithm (Connectivity Mapping) to compare the RI-DKD-GPs's signature with a collection of thousands of transcriptional signatures of bioactive compounds. The sesquiterpene lactone parthenolide was identified as one of the top compounds predicted to reverse the RI-DKD-GPs's signature. Oral treatment of 2 months old Ins2Akita mice with dimethylaminoparthenolide (DMAPT, a water-soluble analogue of parthenolide) for two months at 10 mg/kg/d by gavage significantly reduced urinary ACR. However, in contrast to ramipril, DMAPT also significantly reduced glomerulosclerosis and tubulointerstitial fibrosis. Using a system biology approach, we identified DMAPT, as a compound with a potential add-on value to standard-of-care ACEi-treatment in DKD.
Assuntos
Diabetes Mellitus Tipo 1/tratamento farmacológico , Nefropatias Diabéticas/tratamento farmacológico , Sesquiterpenos/farmacologia , Antagonistas de Receptores de Angiotensina/farmacologia , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Animais , Conectoma/métodos , Nefropatias Diabéticas/etiologia , Nefropatias Diabéticas/metabolismo , Nefropatias Diabéticas/patologia , Regulação da Expressão Gênica/efeitos dos fármacos , Taxa de Filtração Glomerular , Glomérulos Renais/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Sistema Renina-Angiotensina/efeitos dos fármacosRESUMO
New chiral heteroleptic germanium(ii) and tin(ii) metallylenes were obtained using 1-(para-tolylsulfinyl)-3-tosyl-5-tert-butyl-benzene as a non-symmetric O,C,O-chelating pincer ligand. Crystallographic analysis and DFT calculations indicate that the non-symmetric sulfinyl-sulfonyl pincer ligand acts as an O,C,O-coordinating pincer-type-ligand with predominant sulfinyl intramolecular S[double bond, length as m-dash]O coordination to germanium(ii) and tin(ii) centers.
RESUMO
Well-controlled poly(alpha-hydroxyacids) featuring pendant carboxylic acid groups were prepared under mild conditions via DMAP-catalyzed ROP of the O-carboxyanhydrides derived from glutamic and lactic acids.
Assuntos
Anidridos/química , Ácido Glutâmico/química , Poliésteres/química , CatáliseRESUMO
The preparation of the (1-naphthyl)(trifluoromethyl) O-carboxy-anhydride 1 and its use as a chiral derivatizing agent with several alpha-chiral primary amines are reported. The very large Delta delta(RS) values observed in (1)H NMR have been correlated with a marked preference of the corresponding alpha-hydroxy-amides for the eclipsed conformation. In comparison, the related O-methylated amides are shown to adopt staggered conformations, which substantiates the critical role of intramolecular hydrogen bonding in maximizing the anisotropic effect.
Assuntos
Conformação Molecular , Naftalenos/química , Benzilaminas/química , Ligação de Hidrogênio , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Estrutura Molecular , EstereoisomerismoRESUMO
The alpha-lactone equivalent lacOCA exhibits remarkable reactivity compared with lactide in nucleophile-catalyzed ROP. PLAs of controlled molecular weights and narrow polydispersities are typically obtained under mild conditions using DMAP and various protic initiators.