Efficient and Straightforward Synthesis of Tetrahydrocarbazoles and 2,3-Dimethyl Indoles Catalyzed by CAN

A simple protocol was established to synthesize 2,3-dialkyl indoles and various tetrahydrocarbazoles via Fischer indole synthesis. This method uses ceric ammonium nitrate as a catalyst for the Fischer indole synthesis with substituted phenyl hydrazine hydrochlorides and 2-butanone, phenyl propanal, and cyclohexanone. This process is a practical synthetic method for the preparation of various 2,3-disubstituted alkyl indoles and tetrahydrocarbazoles.     

One-pot conversion of phenols to anilines via Smiles rearrangement

A convenient one-pot synthesis of phenols to anilines using 2-chloroacetamide/K₂CO₃/DMF system catalyzed by KI via Smiles rearrangement has been described. The synthesis of extensive amino aromatic products from phenols containing electron withdrawing group, has been performed in moderate to excellent yields to demonstrate the potentiality of this method in bio-medicinal and pharmaceutical applications.     

Synthesis and Biological Activities of Some New Annulated Pyrazolopyranopyrimidines and Their Derivatives Containing Indole Nucleus

The key intermediate 6‐amino‐3‐methyl‐4‐aryl‐1‐(5′‐substituted‐3′‐phenyl‐1H‐indol‐2′‐carbonyl)‐1,4‐dihydropyrano[2,3‐c]pyrazol‐5‐carbonitriles 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h , 3i , 3j , 3k , 3l , 3m , 3n , 3o were prepared by cyclocondensation of 3‐methyl‐1‐(5′‐substituted‐3′‐phenyl‐1H‐indol‐2′‐carbonyl)‐5‐(4H)‐pyrazolones 1a , 1b , 1c with arylidine derivatives of malononitrile 2a , 2b , 2c , 2d , 2e . The compounds 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h , 3i , 3j , 3k , 3l , 3m , 3n , 3o were subjected to cyclocondensation reaction with formamide, formic acid, and carbon disulfide to afford the title compounds 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j , 4k , 4l , 4m , 4n , 4o , 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i , 5j , 5k , 5l , 5m , 5n , 5o , and 6a , 6b , 6c , 6d , 6e , 6f , 6g , 6h , 6i , 6j , 6k , 6l , 6m , 6n , 6o , respectively. The structures of all these previously unknown compounds were confirmed by their spectral studies and elemental analysis. These compounds were screened for their antimicrobial and antioxidant activities.     

Imino <Emphasis Type="Italic">Diels-Alder</Emphasis> Reactions: Efficient Synthesis of 2-Aryl-4-(2′-oxopyrrolidinyl-1′)-1,2,3,4-tetrahydroquinolines catalyzed by Antimony(III) Sulfate

Summary. Antimony(III) sulfate is found to catalyze the imino Diels-Alder reaction of Schiff’s bases with N-vinylpyrrolidin-2-one to afford 2-aryl-4-(2′-oxopyrrolidinyl-1′)-1,2,3,4-tetrahydroquinolines. One-pot synthesis of 1,2,3,4-tetrahydroquinolines from 3-nitro benzaldehyde and aromatic amines with N-vinylpyrrolidin-2-one catalyzed by antimony(III) sulfate is also reported. This catalyst is inexpensive, easily available, and it was also found that catalyst could be recovered quantitatively and reused without much loss of catalytic activity.     

Synthesis of highly functionalized 2(1H)-pyrazinone 3-carboxamide scaffolds

Synthesis of highly functionalized 2(1H)-pyrazinone 3-carboxamide derivatives is reported. A one-pot, two-step process including the base-mediated reaction of N,N-disubstituted aminoacetonitrile derivatives 18 with 3,5-dihalo-2(1H)-pyrazinones 1 afforded substituted aminoacetonitrile pyrazinone derivative 19, which on subsequent oxidation followed by transamidation of the resulting intermediate with primary or secondary amines gave the corresponding highly functionalized 2(1H)-pyrazinone 3-carboxamide derivatives 21.     

A new family of heteroleptic ruthenium(II) polypyridyl complexes for sensitization of nanocrystalline TiO2 films

Two new heteroleptic ruthenium(II) photosensitizers that contains 2,2';6,2'-terpyridine with extended π-conjugation with donor groups, a 4,4'-dicarboxylic acid-2,2'-bipyridine anchoring ligand and a thiocyanate ligand have been designed, synthesized and fully characterized by CHN, mass spectrometry, UV-vis and fluorescence spectroscopies and cyclic voltammetry. The new sensitizers have either 3,5-di-tert-butyl phenyl (m-BL-5) or triphenylamine (m-BL-6) groups, where the molar extinction coefficient of both the sensitizers is higher than the analogous ruthenium dyes. Both the sensitizers were tested in dye-sensitized solar cells using two different redox electrolytes.     

Development and validation of a novel RP-HPLC method for the analysis of reduced glutathione

The objective of this study was the development, optimization, and validation of a novel reverse-phase high-pressure liquid chromatography (RP-HPLC) method for the quantification of reduced glutathione in pharmaceutical formulations utilizing simple UV detection. The separation utilized a C18 column at room temperature and UV absorption was measured at 215 nm. The mobile phase was an isocratic flow of a 50/50 (v/v) mixture of water (pH 7.0) and acetonitrile flowing at 1.0 mL/min. Validation of the method assessed the methods ability in seven categories: linearity, range, limit of detection, limit of quantification, accuracy, precision, and selectivity. Analysis of the system suitability showed acceptable levels of suitability in all categories. Likewise, the method displayed an acceptable degree of linearity (r(2) = 0.9994) over a concentration range of 2.5-60 μg/mL. The detection limit and quantification limit were 0.6 and 1.8 μg/mL respectively. The percent recovery of the method was 98.80-100.79%. Following validation the method was employed in the determination of glutathione in pharmaceutical formulations in the form of a conjugate and a nanoparticle. The proposed method offers a simple, accurate, and inexpensive way to quantify reduced glutathione.     

Highly efficient and chemoselective acetalization and thioacetalization of aldehydes catalyzed by propylphosphonic anhydride (®T3P) at room temperature

Propylphosphonic anhydride (®T3P), a low toxic peptide coupling agent, has been demonstrated to be an efficient catalyst for the chemoselective acetalization and thioacetalization of aldehydes in the presence of ketones. Cyclic and acyclic acetals of diverse aldehydes were obtained in good to excellent yields at room temperature in the presence of a catalytic amount of T3P.     

Active methylene compounds in a very effective approach to 3-substituted isobenzofuranones through tandem aldol/lactonization reactions

In this article we describe a new accessible methodology for the synthesis of isobenzofuran-1(3H)-ones. In this process we exploited an effective, economic, useful and environmentally benign K₂CO₃ catalyzed, solvent-free one-pot tandem aldol-lactonization reaction between active methylene compounds and methyl 2-carboxy benzaldehyde. A particularly simple work-up and purification procedure are additional advantages addressed to a general green chemistry approach to this important class of heterocyclic compounds.