Anti-skin ageing activity of napthoquinones from Arnebia nobilis Reichb.f.

The present isolation and identification of napthoquinones from roots of Arnebia nobilis Reichb.f. can lead to the discovery of new anti-skin ageing ingredient in colour cosmetics. Four compounds have been isolated and purified by rigorous column chromatography. The compounds are identified as β, β-dimethylacryl alkannin (AN-I), acetoxyisovaleryl alkannin (AAN-II), acetyl alkannin (AN-III) and alkannin (AN-IV) by interpretation of spectroscopic data. This study is the first to report the isolation of Acetoxyisovaleryl alkannin (AAN-II) from A. nobilis. The IC₅₀ values of the compounds, determined in human skin cells (human dermal fibroblasts and human keratinocytes) and mouse embryonic fibroblasts (NIH3T3) varied significantly among the four alkannins. Among the four compounds, β-acetoxyisovaleryl alkannin (AAN-II) significantly inhibited hydrogen peroxide (H₂O₂)-induced red blood corpuscle haemolysis and cellular senescence in human dermal fibroblasts. Collagen-I, elastin and involucrin syntheses in human dermal fibroblasts or keratinocytes were up regulated by AAN-II. These results support the potential utility of alkannins as novel anti-ageing ingredients.     

Pyrene-derived novel one- and two-component organogelators

A new class of alkyl-chain-appended pyrene derivatives 4-14 were synthesized and evaluated for their gelation abilities. Depending on the nature of the linking group, these compounds gelated a number of organic solvents, either in the presence or in the absence of the acceptor molecule 2,4,7-trinitrofluorenone (TNF). Compounds with ester, ether, or alkyl linkages gelated a number of hydroxylic and hydrocarbon solvents by means of a charge-transfer interaction with TNF, while compounds with amide, urethane and urea linkers formed gels on their own in a variety of solvents by means of pi-pi stacking and hydrogen-bonding interactions. The Xray crystal structure of urethane (S)-12 showed hydrogen-bonding and stacking features, as suggested by the model. The gels obtained were investigated by spectroscopic and electron microscopic techniques which provided structural insights.     

Anti-microbial activity and film characterization of thiazolidinone derivatives of chitosan

Thiazolidinone derivatives (TDCs) were prepared by converting chitosan into chitosan's Schiff's bases (CSBs), followed by treatment with mercaptoacetic acid. Both CSBs and TDCs were tested for antimicrobial activity against four different bacteria. All TDCs showed comparatively better anti-microbial activity without much affecting basic physical properties of chitosan such as film-forming capacity, tensile strength, etc. This indicates that chitosan derivatives with a thiazolidinone moiety might be a better material for wound dressing.     

Antimony(III) Sulfate Catalyzed Condensation Reaction of Indoles with Carbonyl Compounds

Summary. Antimony sulfate was found to be on effective catalyst for the condensation reaction of indoles with carbonyl compounds at room temperature. This catalyst is inexpensive, easily available and it was also found that this catalyst could be recovered quantitatively and reused without much loss of catalytic activity.     

Facile Regioselective On-Water Synthesis of 4,7-Dihydropyrazolo[1,5-a]Pyrimidines and 4,7-Dihydro[1,2,4]Triazolo[1,5-a]Pyrimidines

Chemistry of Heterocyclic Compounds - Efficient and regioselective on-water synthesis of variously substituted 5-amino-4,7-dihydropyrazolo[1,5-a]pyrimidine-6-carbonitriles and...     

Synthesis of sidechain adapted β-turn mimics for modifying the C-terminus of substance P

Sidechain adapted β-turn mimics of type 1 characterised by a fixed cis-conformation of the peptide chain in the aminopiperidinonecarboxylate scaffold have been synthesised from pyrazinones in order to perform a β-turn scan of the messenger region of substance P. The synthesis of a substance P peptide analogue is also described.     

Coated wire chromium(III) ion-selective electrode based on azamacrocycles

Tetraazacyclotetradecane, tetratosyltetraaza 12C4, and tritosyltriaza 9C3 have been explored as electroactive materials for preparing coated wire ion-selective electrodes (CWISEs) for Cr(III) ions. The best performance was observed for the membrane comprising electroactive material (tetratosyltetraaza 12C4), plasticizer (dibutyl phthalate), and poly(vinyl chloride) in the optimum ratio 5:60:35 (w/w). Linear Nernstian response for this electrode was obtained over the total Cr(III) concentration range of 1×10^–1 to 1×10^–7 M in 0.05 M NH₄NO₃ medium, with a slope of 20±1 mV per decade change. The working pH range of the electrode was 1.8–5.5. Selectivity coefficients of some mono, divalent, and trivalent metal ions were determined. Analyses of electroplating bath solutions, chromating, and effluent samples have been carried out using this CWISE and the results are found to be comparable with those obtained by using conventional methods or by AAS.     

Regioselective synthesis of quinazoline containing novel monoaryl ethers at room temperature

We are herein reporting the regioselective synthesis of quinazoline containing novel monoaryl ethers (quinazoline‐O‐Ar) ( 3a‐3j ) at room temperature without any catalyst. From commercially available 2,4‐dichloro‐6,7‐dimethoxyquinazoline ( 1 ), 4‐chloro was selectively substituted with variety of electronically rich, electronically poor and electronically neutral phenols ( 2a‐2j ). Reaction was carried out in DMF and NaH for 4‐6 hours at room temperature in fairly good yield. The products were purified (>98% pure, hplc) by crystallization to avoid the use of column chromatography.