RESUMEN

The re-epithelialization process gets severely dysregulated in chronic nonhealing diabetic foot ulcers/wounds. Keratinocyte growth factor (KGF or FGF-7) is the major modulator of the re-epithelialization process, which regulates the physiological phenotypes of cutaneous keratinocytes. The existing therapeutic strategies of growth factor administration have several limitations. To overcome these, we have designed a KGF-mimetic peptide (KGFp, 13mer) based on the receptor interaction sites in murine KGF. KGFp enhanced migration and transdifferentiation of mouse bone marrow-derived MSCs toward keratinocyte-like cells (KLCs). A significant increase in the expression of skin-specific markers Bnc1 (28.5-fold), Ck5 (14.6-fold), Ck14 (26.1-fold), Ck10 (187.7-fold), and epithelial markers EpCam (23.3-fold) and Cdh1 (64.2-fold) was associated with the activation of ERK1/2 and STAT3 molecular signaling in the KLCs. Further, to enhance the stability of KGFp in the wound microenvironment, it was conjugated to biocompatible 3D porous polymer scaffolds without compromising its active binding sites followed by chemical characterization using Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, dynamic mechanical analysis, and thermogravimetry. In vitro evaluation of the KGFp-conjugated 3D polymer scaffolds revealed its potential for transdifferentiation of MSCs into KLCs. Transplantation of allogeneic MSCGFP using KGFp-conjugated 3D polymer scaffolds in chronic nonhealing type 2 diabetic wounds (db/db transgenic, 50-52 weeks old male mice) significantly enhanced re-epithelialization-mediated wound closure rate (79.3%) as compared to the control groups (Untransplanted -22.4%, MSCGFP-3D polymer scaffold -38.5%). Thus, KGFp-conjugated 3D porous polymer scaffolds drive the fate of the MSCs toward keratinocytes that may serve as potential stem cell delivery platform technology for tissue engineering and transplantation.

Asunto(s)

Factor 7 de Crecimiento de Fibroblastos , Queratinocitos , Andamios del Tejido , Animales , Ratones , Andamios del Tejido/química , Queratinocitos/efectos de los fármacos , Factor 7 de Crecimiento de Fibroblastos/química , Factor 7 de Crecimiento de Fibroblastos/farmacología , Porosidad , Péptidos/química , Péptidos/farmacología , Cicatrización de Heridas/efectos de los fármacos , Piel/efectos de los fármacos , Piel/patología , Polímeros/química , Polímeros/farmacología , Células Madre Mesenquimatosas/efectos de los fármacos , Células Madre Mesenquimatosas/citología , Células Madre Mesenquimatosas/metabolismo , Masculino , Regeneración/efectos de los fármacos , Materiales Biomiméticos/química , Materiales Biomiméticos/farmacología , Pie Diabético/tratamiento farmacológico , Pie Diabético/patología , Pie Diabético/terapia , Humanos

RESUMEN

An efficient copper-catalyzed method for the synthesis of tetrazolo[5,1-a]isoquinolines has been developed starting from alkenyl-1,2-bis(boronates). The domino reaction underwent a Suzuki-Miyaura cross-coupling reaction and an azidation followed by an in situ [3 + 2] cycloaddition. Regioselective synthesis has been demonstrated by inverting the Suzuki-Miyaura cross-coupling reaction and the azidation.

RESUMEN

A palladium-catalyzed chelation-assisted direct aldehyde C-H bond amidation of quinoline-8-carbaldehydes with an amine was developed under mild reaction conditions. A wide range of amides were obtained in good to excellent yields from aldehyde with a variety of aniline derivatives and aliphatic amines. Our methodology was successfully applied to synthesize known DNA intercalating agents and can be easily scaled up to a gram scale.

RESUMEN

An efficient stereo-controlled synthesis of enyne and enediyne derivatives, via sequential Suzuki-Miyaura coupling reactions from easily prepared 1-alkene-1,2-diboronic esters and alkynyl bromides, is reported. The resulting enyne boronic esters were subjected to Borono-Mannich and Suzuki coupling reactions independently to obtain α,ß-unsaturated aminoester and tri-substituted olefin derivatives, respectively. Additionally, divergent syntheses of triazole and cyclopropylboronate derivatives are also reported.

RESUMEN

A facile double oxidative annulation of (en-3-yn-1-yl)phenylbenzamides was developed allowing us to synthetize fused tetracyclic compounds. Under copper catalysis, the reaction proceeds with high efficiency and leads to new indolo[1,2-a]quinolines via a decarbonylative double oxidative annulation. On the other hand, under ruthenium catalysis, new isoquinolin-1[2H]-ones were obtained via a double oxidative annulation.

RESUMEN

We have developed a method for Pd-catalyzed direct C-H arylation of quinoline-8-carbaldehydes with either aryl iodides or aryl diazonium salts for the synthesis of aryl quinolinyl ketones. Aryl iodide substituted with an electron-donating group favors the reaction, whereas aryl diazonium salt substituted with an electron-withdrawing group showed excellent reactivity. A range of aryl quinolinyl ketones were synthesized in good-to-excellent yields, with very good functional group tolerance. Our methodology was successfully applied to synthesize highly potent tubulin polymerization inhibitors and can be easily scaled up to a gram scale.

Asunto(s)

Paladio , Quinolinas , Aldehídos , Catálisis , Estructura Molecular , Yoduros , Cetonas

RESUMEN

An environmentally benign, cost-effective and scalable process for the preparation of both the enantiomers of 3-hydroxytetrahydrofuran has been developed. pH-Controlled ring opening of enantiomerically pure epichlorohydrins with cyanohydrin is the key step of the process. The entire protocol does not require any column purification.

Asunto(s)

Compuestos Epoxi , Nitrilos , Concentración de Iones de Hidrógeno , Estereoisomerismo

RESUMEN

A Simmons-Smith stereodefined procedure for the synthesis of cyclopropyl-1,2-bis(boronates) has been developed starting from the corresponding alkenes. The resulting compounds were then subjected to regioselective Suzuki-Miyaura couplings to produce diversely tri- or tetra-substituted arylcyclopropanes in good yields. Further functionalization with 2-lithiothiophene provided 1,2-bis(aryl)cyclopropanes.

RESUMEN

Remdesivir, the first drug approved by the FDA to treat COVID-19, is in high demand for patients infected with the SARS-CoV-2 virus. Herein, we report a facile approach minimizing the protecting group manipulations to afford remdesivir in good overall yield.

RESUMEN

Synthesis of hindered alkyl aryl ether derivatives (R-O-Ar) remains a huge challenge and highly desirable in organic and medicinal chemistry because extensive substitution on the ether bond prevents the undesired metabolic process and thus avoids rapid degradation in vivo. Herein, we report an unprecedented hindered alkoxylation of picolinamide attached aromatic amines using economic copper salt and organic peroxide to get highly desirable α-tertiary alkyl aryl ethers.

RESUMEN

An atom-economical and efficient route for the direct amidation and amination of aryl C-H bonds using our synthesized recyclable heterogeneous Cu-MnO catalyst is reported here. The direct C-H amidation was carried out using a simple amide without any preactivated coupling partner, and simple air was used as the sole oxidant. The reaction proceeds very smoothly with a broad range of substrates containing numerous functional groups in very good to excellent yields. Direct C-H aminations with a secondary amine were carried out under base-, ligand-, and external oxidant-free conditions in very good to excellent yields in very mild conditions. Both the amidation and amination can be scaled up on a gram scale with similar yields. The major advantage is that our catalyst is recyclable and reused several times without any significant loss of reactivity.

RESUMEN

A stereoselective and convenient route has been demonstrated to access (Z)-1,2-diazido alkenes from the corresponding 1,2-diboronic esters via a copper-mediated reaction with sodium azide. Alternately, mono-functionalization was regioselectively carried out with trimethylsilyl azide as an azidation reactant. The in situ conversion of bis-azides to the corresponding bis-triazoles can be readily achieved in the presence of copper sulfate and sodium ascorbate, while the modification of the catalytic system opened a new convenient route to bis-triazolo-pyrazines, a new class of fused heterocycles.

RESUMEN

A room-temperature C-H bond functionalization of benzamides has been developed by merging a photocatalyst with a cobalt catalyst for the synthesis of isoindolone spirosuccinimides. The reaction proceeds in aerobic conditions and does not require any sacrificial external oxidants such as Ag(I) or Mn(III) salts. Visible light activates the photocatalyst, and it acts as an electron-transfer reagent and helps in the fundamental organometallic steps by modulating the oxidation state of the cobalt complex. This C-H bond functionalization and spirocyclization showed wide substrate scope and good functional group tolerance. A possible reaction mechanism was proposed from the experimental outcome, showing that C-H bond activation is irreversible and not the rate-determining step.

RESUMEN

The World Health Organization (WHO) has listed daclatasvir (DCV), symmetrical arene, as one of the essential medicines for human health. DCV manufacturing is usually carried out in a non-continuous or "batch" approach over multiple locations and is severely limited by long production times (3-10 days), resulting in non-affordability (highly expensive) and disruption of the potential chain supply. Here, we report the total process system including the development of a novel electro-flow reactor containing patterned electrodeposited Ni or Pt nanoparticles over a copper electrode for a C-C coupling reaction in a co-reductant/oxidant-free, ultra-fast process for symmetrical substituted/unsubstituted biphenyl synthesis. This method was further extended to a new generation commercial batch synthetic route for continuous flow ultra-fast daclatasvir synthesis in 33.2 min. We envisage that this micro-electro-flow reactor (µ-EFR) system platform will substantially enable advances in continuous-µ-flow fine chemical manufacturing, multistep reaction sequences, reaction devising equipment, and real-time extraction.

RESUMEN

Herein we report a simple synthetic protocol for N-doped yellow TiO2 (N-TiO2 ) hollow spheres as an efficient visible-light-active photocatalyst using aqueous titanium peroxocarbonate complex (TPCC) solution as precursor and NH4 OH. In the developed strategy, the ammonium ion of TPCC and NH4 OH acts as nitrogen source and structure-directing agent. The synthesized N-TiO2 hollow spheres are capable of promoting the synthesis of active esters of N-hydroxyimide and alcohol through simultaneous selective oxidation of alcohol to aldehyde followed by cross-dehydrogenative coupling (CDC) under ambient conditions upon irradiation of visible light. It is possible to develop a novel and cost-effective one-pot strategy for the synthesis of important esters and amides on gram scale using the developed strategy. The catalytic activity of N-TiO2 hollow spheres is much superior to that of other reported N-TiO2 samples as well as TiO2 with varying morphology.

RESUMEN

An efficient photocatalytic method was developed for the remote C5-H bond carboxylation of 8-aminoquinoline amide and sulfonamide derivatives. This methodology uses in situ generated •CBr3 radical as a carboxylation agent with alcohol and is further extended to a variety of arenes and heteroarenes to synthesize the desired carboxylated product in moderate-to-good yields. The reaction proceeding through a single electron transfer pathway was established by a control experiment, and a butylated hydroxytoluene-trapped aryl radical cation intermediate in high-resolution mass spectrometry was identified.

RESUMEN

CdS sheet-rGO nanocomposite as a heterogeneous photocatalyst enables visible-light-induced photocatalytic reduction of aromatic, heteroaromatic, aliphatic and sulfonyl azides to the corresponding amines using hydrazine hydrate as a reductant. The reaction shows excellent conversion and chemoselectivity towards the formation of the amine without self-photoactivated azo compounds. In the adopted strategy, CdS not only accelerates the formation of nitrene through photoactivation of azide but also enhances the decomposition of azide to a certain extent, which entirely suppressed formation of the azo compound. The developed CdS sheet-rGO nanocomposite catalyst is very active, providing excellent results under irradiation with a 40 W simple household CFL lamp.

RESUMEN

The stereoselective total synthesis of cytotoxic marine macrolide callyspongiolide has been reported. The 14-membered macrolactone ring along with Z-olefin in the molecule was constructed via an intramolecular Horner-Wadsworth-Emmons olefination in a Z-selective fashion. The other E-olefinic moiety as well as the C9 stereocenter was introduced via stereoselective addition of the methyl group in an SN2' fashion. The C5 stereocenter was installed via Sakurai allylation, whereas the C7 center was fixed by Jacobsen hydrolytic kinetic resolution. The C12 methyl and C13 hydroxy centers were fixed via Macmillan coupling reaction. The macrolactone core with a vinyl iodide side chain was coupled with the known alkyne fragment to complete the synthesis.

RESUMEN

Herein, we report the development of a hydrogenated MoS2 QD-TiO2 (HMT) heterojunction as an efficient photocatalytic system via a one-pot hydrothermal reaction followed by hydrogenation. This synthetic strategy facilitates the formation of MoS2 QDs with an enhanced band gap and a proper heterojunction between them and TiO2, which accelerates charge transfer process. Hydrogenation leads to oxygen vacancies in TiO2, enhancing the visible light absorption capacity through narrowing its band gap, and sulfur vacancies in MoS2, which enhance the active sites for hydrogen adsorption. Due to the band gap reduction of hydrogenated TiO2 and the band gap enhancement of the MoS2 QDs, the energy states are rearranged to create a reverse movement of electrons and holes facilitated the charge transfer process which enhance life-time of photo-generated charges. The photocatalyst showed stable, efficient and exceptionally high noble metal free sunlight-induced hydrogen production with a maximum rate of 3.1 mmol g-1 h-1. The developed synthetic strategy also provides flexibility towards the shape of the MoS2, e.g. QDs/single or few layers, on TiO2 and offers the opportunity to design novel visible light active photocatalysts for different applications.

RESUMEN

In the presence of molecular oxygen, a {001}-faceted nanocrystalline anatase TiO2 catalyst enabled the selective oxidation of nonactivated aliphatic alcohols to the corresponding aldehydes or ketones under visible light. The reaction shows excellent conversion and selectivity towards the formation of the carbonyl products without over-oxidation to the corresponding carboxylic acids. The exceptional reactivity of the catalyst is possibly due to the absorption of visible light originating from a stronger interaction of alcohol with the {001} facet, which facilitates the modification of the band structure of TiO2 , thus facilitating the photogenerated hole transfer and subsequent oxidation processes. The experimental results have also been corroborated by first-principles quantum chemical DFT calculations.