1,3-dihydro-2H-indol-2-ones derivatives: Design, Synthesis, in vitro antibacterial, antifungal and antitubercular study

Traceability of Satsuma Mandarin (Citrus unshiu Marc.) Honey through Nectar/Honey-Sac/Honey Pathways of the Headspace, Volatiles, and Semi-Volatiles: Chemical Markers

Headspace solid-phase microextraction (HS-SPME) and ultrasonic solvent extraction (USE), followed by GC-MS/FID, were applied for monitoring the nectar (NE)/honey-sac (HoS)/honey (HO) pathways of the headspace, volatiles, and semi-volatiles. The major NE (4 varieties of Citrus unshiu) headspace compounds were linalool, α-terpineol, 1H-indole, methyl anthranilate, and phenylacetonitrile. Corresponding extracts contained, among others, 1H-indole, methyl anthranilate, 1,3-dihydro-2H-indol-2-one and caffeine. The major HoS headspace compounds were linalool, α-terpineol, 1,8-cineole, 1H-indole, methyl anthranilate, and cis-jasmone. Characteristic compounds from HoS extract were caffeine, 1H-indole, 1,3-dihydro-2H-indol-2-one, methyl anthranilate, and phenylacetonitrile. However, HO headspace composition was significantly different in comparison to NE and HoS with respect to phenylacetaldehyde and linalool derivatives abundance that appeared as the consequence of the hive conditions and the bee enzyme activity. C. unshiu honey traceability is determined by chemical markers: phenylacetaldehyde, phenylacetonitrile, linalool and its derivatives, as well as 1H-indole, 1,3-dihydro-2H-indol-2-one, and caffeine.

Evaluation of Antioxidant, Antimicrobial and Anticancer activity of Thiazole Tagged Isatin Hydrazones

Isatin and its derivatives is versatile lead molecule for potential bioactive agents and shows wide spectrum of activities. In this study, we evaluated antioxidant, antimicrobial and cytotoxic activity of isatin-3-[N2-(2-benzalaminothiazol-4-yl)] hydrazone derivatives using well defined models. Antioxidant activity of the isatin derivatives (Va-Vj) was evaluated by using the 1, 1-diphenyl-2-picryl hydrazine radicals scavenging assay. The antimicrobial activity is evaluated by cup plate method and anticancer activity is evaluated by MTT assay against HBL-100 & HeLa cell lines. Compound Vh (R = 5-Cl, R1 = OH & R2 = OCH3) showed good antioxidant activity with the IC50 of 8.09 M. In addition Ve and Vi have showned most active antibacterial activity against Bacillus subtilis, Staphylococcus aureus and Escherichia coli with a Zone of Inhibition (mm) 20, 16, 18 and 14, 12, 15 on respective organism at 100 g/disc. The compound Vi have produced a good antifungal activity against Aspergillus niger and Clostridium vericulata with the zone of inhibition values of 9 and 8 mm respectively. These isatin derivatives also among the test compounds, compound Vd (R = 5-Cl, R1 = OH & R2 = OCH3) and compound Vh (R = 5-Cl, R1 = OH & R2 = OCH3) have shown nearly equal cytotoxic activity with IC50 values of 246.53 mM and 247.29 mM against HBL-100 cell lines and HeLa cell lines respectively. From the results, isatin derivatives showed powerful antioxidant activity, antimicrobial and anticancer activity may be due to the halogens substituted at 5th position of isatin. The standard drugs used were ampicillin, clotrimazole, cisplatin and ascorbic acid for antibacterial, antifungal, anticancer and antioxidant respectively.

New Efficient Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones Catalyzed by Benzotriazolium-Based Ionic Liquids under Solvent-Free Conditions

An efficient synthesis of novel 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) and their derivatives, using Brønsted acidic ionic liquid [C₂O₂BBTA][TFA] as a catalyst, from the condensation of aryl aldehyde, β-ketoester and urea was described. Reactions proceeded smoothly for 40 min under solvent-free conditions and gave the desirable products with good to excellent yields (up to 99%). The catalyst could be easily recycled and reused with similar efficacies for at least six cycles.

CaCl2, Bisoxazoline, and Malonate: A Protocol for an Asymmetric Michael Reaction

A mild protocol for the asymmetric Michael addition of dimethyl malonate to various α,β-unsaturated carbonyl compounds was developed. The salient feature of this methodology is that a cheap and environmentally friendly Lewis acid, CaCl2, was used as a catalyst. An aminoindanol- and pyridine-derived ligand provided in the presence of CaCl2 Michael adducts in moderate to high enantioselectivities. The scope of the reaction was demonstrated.

Hydrolysis and Hydrazinolysis of Isatin-Based Ald- and Ketazines

The hydrolysis of isatin aldazine4a–dafforded the unexpected 3,3′-(hydrazine-1,2-diylidene)bis(indolin-2-one) (5) and 1,2-di(arylidene)hydrazines6a–dthrough dual hydrolysis of4a–d. A mechanism to explain the formation of5and6a–dwas proposed. In addition, the hydrazinolysis of4a–dyielded 3-hydrazonoindolin-2-one (2) and 1,2-di(arylidene)hydrazines6a–dinstead of hydrazones17a–d, while hydrazinolysis of isatin ketazine5gave the expected 3-hydrazonoindolin-2-one (2). These results indicated the ability of the title compounds for unusual hydrolysis and hydrazinolysis reactions.

A mini-review on Biginelli adducts with notable pharmacological properties

Since the disclosure of Biginelli reaction by the chemist Pietro Biginelli, functionalized 3,4-dihydropyrimidin-2(1H)-ones/thiones (DHPMs) have emerged as prototypes for the design of compounds with a broad variety of biological activities. This mini-review describes over 100 Biginelli adducts demonstrated to be promising anticancer, inhibitors of calcium channel, anti-inflammatory, antimicrobial and antioxidant agents. Thus, this compilation presents the most notable in vitro and in vivo results for such fascinating class of organic compounds.

Synthesis of isatin thiosemicarbazones derivatives: in vitro anti-cancer, DNA binding and cleavage activities

New derivatives of thiosemicarbazone Schiff base with isatin moiety were synthesized L1-L6. The structures of these compounds were characterized based on the spectroscopic techniques. Compound L6 was further characterized by XRD single crystal. The interaction of these compounds with calf thymus (CT-DNA) exhibited high intrinsic binding constant (k(b)=5.03-33.00×10(5) M(-1)) for L1-L3 and L5 and (6.14-9.47×10(4) M(-1)) for L4 and L6 which reflect intercalative activity of these compounds toward CT-DNA. This result was also confirmed by the viscosity data. The electrophoresis studies reveal the higher cleavage activity of L1-L3 than L4-L6. The in vitro anti-proliferative activity of these compounds against human colon cancer cell line (HCT 116) revealed that the synthesized compounds (L3, L6 and L2) exhibited good anticancer potency.

Titanium dioxide supported on MWCNTs as an eco-friendly catalyst in the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones accelerated under microwave irradiation

Some transition metal oxides supported on MWCNTs were prepared as novel heterogeneous catalysts using the facile processes. These catalysts were used for the synthesis of Biginelli compounds under microwave irradiation.

Simple access to 5-carboalkoxy-2,3-dihydro-4H-pyran-4-ones via domino acylative electrocyclization: the first three step total synthesis of the dihydronaphthopyran-4-one class of natural products

5-Carboalkoxy-2,3-dihydropyran-4-ones synthesised via domino C-acylation/6π-oxaelectrocyclization protocol was employed as a starting material for the first three step total synthesis of dihydronaphthopyran-4-one class of natural products.

Synthesis of thiocarbohydrazide and carbohydrazide derivatives as possible biologically active agents

Abstract

A series of new β-isatin aldehyde-N,N′-thiocarbohydrazone, bis-β-isatin thiocarbohydrazones, bis-β-isatin carbohydrazones was synthesized by condensation of 5-substituted isatin with thiocarbohydrazide or carbohydrazide. The chemical structures of the newly synthesized compounds were confirmed by FT-IR, ¹H NMR, and mass spectral analysis. The synthesized compounds were evaluated for in vitro antiviral activity against various strains of DNA and RNA viruses, but exhibited moderate antiviral activity compared with the reference compounds. Among all the compounds 6c exhibited the highest chemoprevention activity in a two-stage mouse-skin carcinogenesis test.

Graphical abstract

Microwave-Assisted Synthesis and Antibacterial Activity of Methyl 1-{2-[4-Amino-5-(Naphthalen-1-yl)-4H-1,2,4-Triazol-3-Ylthio]ethyl}-1H-Indole-3-Carboxylate Derivatives

Twelve new Schiff bases containing a disubstituted 1,2,4-triazole and a monosubstituted indole linked by a thioethyl group were efficiently synthesised via a method employing microwave irradiation. Compared with a conventional method of heating at 100 °C, yields were increased from 46–48 to 82–92% and the reaction times were reduced from 20–25 h to 4–7 min. The structures of these novel hexacyclic Schiff bases were characterised by their spectral data and elemental analysis. Evaluation of their antibacterial activity showed that many of them possess excellent activity against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis.

Dicoumarol complexes of Cu(II) based on 1,10-phenanthroline: synthesis, X-ray diffraction studies, thermal behavior and biological evaluation

A series of Cu(II) complexes containing dicoumarol derivatives and 1, 10-phenanthroline have been synthesized. Structural and spectroscopic properties of ligands were studied on the basis of mass spectra, NMR ((1)H and (13)C) spectra, FT-IR spectrophotometry and elemental analysis, while physico-chemical, spectroscopic and thermal properties of mixed ligand complexes have been studied on the basis of infrared spectra, mass spectra, electronic spectra, powder X-ray diffraction, elemental analysis and thermogravimetric analysis. X-ray diffraction study suggested the suitable octahedral geometry for hexa-coordinated state. The kinetic parameters such as order of reaction (n), energy of activation (Ea), entropy (S(*)), pre-exponential factor (A), enthalpy (H(*)) and Gibbs free energy (G(*)) have been calculated using Freeman-Carroll method. Ferric-reducing antioxidant power (FRAP) of all complexes were measured. All the compounds were screened for their antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Streptococcus pyogenes and Bacillus subtilis, while antifungal activity against Candida albicans and Aspergillus niger have been carried out. Also compounds against Mycobacterium tuberculosis shows clear enhancement in the anti-tubercular activity upon copper complexation.

Mechanistic studies on Lewis acid catalyzed Biginelli reactions in ionic liquids: evidence for the reactive intermediates and the role of the reagents

This paper describes the use of common Lewis acids supported in imidazolium-based ionic liquids as the catalysts to promote the Biginelli reaction. The ionic liquid effect and the reaction mechanism are discussed on the basis of nuclear magnetic resonance (NMR), electrospray ionization mass spectrometry (ESI-MS), and theoretical calculations. Indeed, the results showed that the ionic medium plays a fundamental role in the synthesis of biologically active dihydropyrimidinones due to the stabilization of the charged intermediates proposed in the mechanism. When conducted in an ionic liquid as solvent, the reaction mechanism is more complex than in other Lewis acid catalyzed Biginelli reactions.