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1.
Chem Commun (Camb) ; 60(51): 6544-6547, 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38842029

RESUMO

Chemoselective oxidation of aromatic and heteroaromatic aldehydes (>45 examples) to their corresponding carboxylic acids has been developed. Potassium tert-butoxide acts as an oxygen source during this transformation that delivers the corresponding acids without chromatographic purifications. The use of bench-top reagents, operational simplicity, and high level of chemo-selectivity with respect to oxidation of the least preferred aldehyde functionality, in the presence of more susceptible functional groups, are some of the highlights of this strategy.

2.
Org Biomol Chem ; 22(17): 3502-3509, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38618907

RESUMO

An expeditious metal free C-3 alkylation of indoles and its NIS-mediated deviation to indolo[2,3-b]quinolines is reported. This protocol, executed in aqueous HFIP has broad substrate scope and is well inclined towards the ideas of sustainable chemistry. Applications of these strategies in accessing bioactive natural products like vibrindole, norcryptotakeine, neocryptolepine and indenoindolone scaffolds has also been demonstrated.

3.
Proc Natl Acad Sci U S A ; 120(46): e2312907120, 2023 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-37922331

RESUMO

Metallosurfactants, defined here as hydrophobic metal-containing groups embedded in hydrophilic units when dispersed in water, emanate in the formation of metallomicelles. This approach continues to attract great interest for its ability to serve as micellar catalysts for various metal-mediated chemical transformations in water. Indeed, relevant to green chemistry, micellar catalysis plays a preeminent function as a replacement for organic solvents in a variety of chemical reactions. There are several methods for the interaction of metal complexes (catalysts or catalyst precursors) and surfactants for producing micellar aggregates. A very effective manner for achieving this involves the direct bonding of the metal center to the amphiphilic polymeric materials. Herein, we describe the synthesis of a metallosurfactant containing a palladium complex covalently incorporated into a CO2-based triblock polycarbonate derived using a dicarboxylic acid chain-transfer agent. This amphiphilic polycarbonate was shown to self-assemble in water to provide uniform and spherical micelles, where the catalytic metal center is located in the hydrophobic portion of the micelle. The resulting metallosurfactant was demonstrated to effectively catalyze carbon-carbon coupling reactions at very low catalyst loadings.

4.
Environ Pollut ; 336: 122489, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37666460

RESUMO

A pH controlled cleavability unfolds the 3-in-1 surfactant feature of an ester-bonded gemini surfactant, 2, 2'-[(oxybis (ethane-1,2-diyl))bis (oxy)]bis (N-hexadecyl-N,Ndimethyl-2-oxoethanaminium) dichloride (C16-C4O2-C16), by reinforcing in-situ mixed micellization between cleaved components at non-neutral pH (pH 3,12). The triplicity is assigned to two mixed-micelle variants at pH 3 and pH 12 besides the unhydrolyzed C16-C4O2-C16 at pH 7. The pH-controlled aggregation of such trichotomic surfactant dramatically enhances the micellar solubilization/cosolubilization of PAHs viz. naphthalene (Np), phenanthrene (Ph), pyrene (Py), perylene (Pe). The cosolubilization of binary/ternary PAH mixtures in such remarkable micellar assemblies at pH 3, 7 and 12 yields intriguing synergistic or antagonistic solubility outcomes correlated to PAH-PAH and PAH-micelle interactions. This study provides valuable insights into the potential applications of the ester-bonded gemini surfactant for the cosolubilization of undesirable hydrophobic compounds at natural sites having variable pH.

5.
Int J Biol Macromol ; 234: 123718, 2023 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-36801307

RESUMO

An ultra-stretchable, quickly self-healable, adhesive hydrogel with efficient anti-oxidant and anti-bacterial activities makes it potential wound dressing material, particularly in healing skin wounds. However, it is highly challenging to prepare such hydrogels with a facile and efficient material design. Given this, we opine the synthesis of medicinal plant Bergenia stracheyi extract-loaded hybrid hydrogels of biocompatible and biodegradable polymers like Gelatin, Hydroxypropyl cellulose, and Polyethylene glycol with acrylic acid via in situ free radical polymerization reaction. The selected plant extract is rich in phenols, flavonoids, and tannins and found to have important therapeutic benefits such as anti-ulcer, anti-Human Immunodeficiency Virus, anti-inflammatory, and burn wound healing effects. The polyphenolic compounds in the plant extract interacted strongly via hydrogen bonding with -OH, -NH2, -COOH, and C-O-C groups of the macromolecules. The synthesized hydrogels were characterized by fourier transform infrared spectroscopy and rheology. The as-prepared hydrogels demonstrate ideal tissue adhesion, excellent stretchability, good mechanical strength, broad-band anti-bacterial capability, and efficient anti-oxidant properties, in addition to quick self-healing and moderate swelling properties. Thus, the aforementioned properties attract the potential use of these materials in the biomedical field.


Assuntos
Adesivos , Antioxidantes , Antioxidantes/farmacologia , Antioxidantes/química , Polímeros , Hidrogéis/química , Antibacterianos/farmacologia , Antibacterianos/química , Extratos Vegetais/farmacologia , Bactérias
6.
RSC Adv ; 12(18): 11318-11344, 2022 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-35425043

RESUMO

The advancements in the field of mechanically interlocked molecular systems (MIMs) has concurrently restructured the material chemistry frontiers and provided ample scope to explore new dimensions for applications and diversity creation. Among all these molecular entities, rotaxanes have a special locale and many research groups over the globe have contributed to their current niche in supramolecular chemistry. From refinements for better yielding synthetic strategies to their application oriented designs, this field has come a long way and is well inclined for further developments. In this review, we aim to document the contemporary developments in the synthesis of phenanthroline (phen) based rotaxanes. In addition to providing a comprehensive account of various subtypes of these rotaxanes and their stitching strategies, their applications, wherever discernible, will be duely highlighted.

7.
J Org Chem ; 87(9): 5744-5759, 2022 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-35389647

RESUMO

A series of [2]rotaxanes with various functional groups in the axle component was synthesized by the oxidative dimerization of alkynes, which is mediated by a macrocyclic phenanthroline-Cu complex. The rotaxanes were fully characterized by spectroscopic methods, and the structure of a rotaxane was determined by X-ray crystallographic analysis. The interaction between the ring component and the axle component was studied in detail to understand the conformation of the rotaxanes. The presence of the hydrogen bond between the phenanthroline moiety in the macrocyclic component and the acidic proton in the axle component influenced the conformation of rotaxane.


Assuntos
Rotaxanos , Alcinos/química , Ligação de Hidrogênio , Conformação Molecular , Fenantrolinas , Rotaxanos/química
8.
Food Chem ; 376: 131925, 2021 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-34973641

RESUMO

Nanoemulsion encapsulated in the hydrogel beads are important entrants for loading hydrophobic active ingredients for enhancing their bioavailability and biological activities relevant in the pharmaceutical, food and cosmetic industries. Herein, we report the formulation of curcumin-loaded nanoemulsion encapsulated in ionotropic hybrid hydrogel beads of alginate, chitosan, gelatin and polyethylene oxide for effective delivery of curcumin. The release behaviour in simulated gastric and intestinal fluids (SGF and SIF) at 37 °C showed faster release in SGF which could be explained on the basis of mesh size, the extent of hydration and the complexation of the curcumin with the Ca2+ ions present within the hydrogel network. The free radical scavenging and antibacterial activities of the released curcumin in SGF were significantly greater than in SIF. This study shows promises of such hybrid systems, ignored so far, for proper encapsulation, protection and delivery of curcumin for the development of functional foods and pharmaceutics. The high structural stability of these nanoemulsion carriers and their effective delivery of curcumin provide a novel and tailored formulation out of existing polymers with plethora of advantages for oral drug delivery. Moreover, this study opens new door for different possibilities to improve the physicochemical characteristics and delivery of bioactive molecules like curcumin.

9.
Chemistry ; 26(71): 17005-17010, 2020 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-32783222

RESUMO

Previously unknown entities in the form of 1,2,3,4,5,6,7,8,9,10-decahydroxydecalins (DHDs) have been conceptualized and the first member of this class, an inosito-inositol, has been synthesized from aromatic hydrocarbon naphthalene following a flexible strategy that is amenable to diversity creation. The DHD accessed here has been subjected to preliminary in silico evaluation with Aß and may hold some promise in Alzheimer's disease therapeutics.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides , Peptídeos beta-Amiloides/metabolismo , Simulação por Computador , Formação de Conceito , Humanos , Inositol/química
10.
Org Lett ; 17(14): 3604-7, 2015 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-26151627

RESUMO

A unified, stereocontrolled, regenerative γ-butyrolactone annulation approach has been conceptualized and validated through syntheses of a range of oligo-THFs. The new protocol is short (four steps), simple (table-top reagents), and efficient (50-61% overall yields). Although the scope of this approach is unlimited, it has been demonstrated up to five iterations on commercial γ-butyrolactone to assemble six fused tetrahydrofuran moieties in a staircase-like architecture. A selection of exploratory transformations is presented to exemplify the potential applications of this protocol.


Assuntos
4-Butirolactona/química , Furanos/síntese química , Lactonas/química , Catálise , Furanos/química , Indicadores e Reagentes/química , Estrutura Molecular , Estereoisomerismo
11.
Eur J Med Chem ; 66: 238-45, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23811086

RESUMO

A series of ursolic acid-1-phenyl-1H-[1,2,3]triazol-4-ylmethylester congeners have been designed and synthesized in an attempt to develop potent antitumor agents. A regioselective approach using Huisgen 1,3-dipolar cycloaddition reaction of ursolic acid-alkyne derivative with various aromatic azides was employed to target an array of triazolyl derivatives in an efficient manner. Their structures were confirmed by using (1)H NMR, (13)C NMR, IR and MS analysis. All the compounds were evaluated for anti-cancer activity against a panel of four human cancer cell lines including A-549 (lung), MCF-7 (breast), HCT-116 (colon), THP-1 (leukemia) and a normal human epithelial cell line (FR-2) using sulforhodamine-B assay. The pharmacological results showed that most of the compounds displayed high level of antitumor activities against the tested cancer cell lines compared with ursolic acid. Compounds 7b, 7g, 7p and 7r were found to be the most potent compounds in this study.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Triazóis/síntese química , Triazóis/farmacologia , Triterpenos/química , Antineoplásicos/química , Linhagem Celular Tumoral , Técnicas de Química Sintética , Humanos , Concentração Inibidora 50 , Triazóis/química , Ácido Ursólico
12.
Food Chem ; 138(1): 693-700, 2013 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-23265542

RESUMO

Essential oil from the aerial parts of Artemisia indica was analysed by GC-FID and GC-MS. A total of 43 compounds representing 96.8% of the oil were identified and the major components were found to be artemisia ketone (42.1%), germacrene B (8.6%), borneol (6.1%) and cis-chrysanthenyl acetate (4.8%). Antimicrobial activity of the oil was evaluated against seven clinically significant bacterial and two fungal strains. The essential oil and its major constituents exhibited moderate to potent, broad-spectrum antibacterial and antifungal activities targeting both Gram-positive and Gram-negative bacteria. In vitro cytotoxicity evaluation against four human cancer cell lines THP-1 (leukemia), A-549 (lung), HEP-2 (liver) and Caco-2 (colon) showed that the essential oil exhibited concentration dependant growth inhibition in the 10-100 µg/ml dilution range, with IC(50) values of 10 µg/ml (THP-1), 25 µg/ml (A-549), 15.5 µg/ml (HEP-2) and 19.5 µg/ml (Caco-2). It was interesting to note that the essential oil also exhibited potent antioxidant activity.


Assuntos
Anti-Infecciosos/química , Antioxidantes/química , Artemisia/química , Citotoxinas/química , Inibidores do Crescimento/química , Óleos Voláteis/química , Óleos de Plantas/química , Anti-Infecciosos/farmacologia , Antioxidantes/farmacologia , Bactérias/efeitos dos fármacos , Linhagem Celular Tumoral , Citotoxinas/farmacologia , Fungos/efeitos dos fármacos , Inibidores do Crescimento/farmacologia , Humanos , Testes de Sensibilidade Microbiana , Óleos Voláteis/farmacologia , Óleos de Plantas/farmacologia
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