Preliminary results from India-based Neutrino Observatory detector R&;D programme

We are currently developing and studying the performance of glass RPC prototypes, under the INO detector R&D programme. While we were successful in building and characterising a large number of chambers using local glass, these have met with severe aging problems after a few months of continuous operation. We have then built a couple of RPCs using a Japanese glass. We report in this paper on our long term stability tests of these RPCs. We also present some of our recent results on tracking of cosmic ray muons in a stack of glass RPCs. India-based Neutrino Observatory Collaboration     

Ferulone A and ferulone B: two new coumarin esters from Ferula orientalis L. roots

Ferula orientalis (Apiaceae) is a well-known perennial herb growing wild in Iran used in traditional medicine. To perform phytochemical studies, dried ground roots of F. orientalis were sequentially Soxhlet-extracted using n-hexane, dichloromethane and methanol. A combination of vacuum liquid chromatography and preparative thin-layer chromatographic analyses were performed to isolate coumarin esters. The structures of the isolated compounds were elucidated by spectroscopic means, and in vitro free-radical-scavenging property was determined by the DPPH assay. Two new coumarin esters, 7-O-(4,8,12,16-tetrahydroxy-4,8,12,16-tetramethyl-heptadecanoyl)-coumarinand 7-O-(4-hydroxy-4,8,12-trimethyl-trideca-7,11-dienoyl)-coumarin, named ferulone A and ferulone B, respectively, were isolated from the n-hexane extract of the roots of F. orientalis. Both compounds showed a low level of free-radical-scavenging property with the RC₅₀ values of 0.252 and 0.556 mg/mL for compounds 1 and 2, respectively, as opposed to that of the positive control (quercetin) 0.004 mg/mL. This is the first report on the purification of coumarin esters from the genus Ferula.     

Copper(I) Complexes of N-(2-{[(2E)-2-(4-Nitrobenzylidenyl)Hydrazinyl]Carbonyl}Phenyl)Benzamide and Triphenylphosphine: Synthesis,Characterization and Luminescence Properties

Copper(I) complexes of the formula [Cu(L)(PPh₃)₂]X (1–4) (X = Cl(1), ClO₄(2), BF₄(3) and PF₆(4)) [where L = N-(2-{[(2E)-2-(4-nitrobenzylidenyl)hydrazinyl]carbonyl}phenyl)benzamide; PPh₃ = triphenylphosphine] have been prepared by the condensation of N-[2-(hydrazinocarbonyl)phenyl]benzamide with 4-nitrobenzaldehyde followed by the reaction with CuCl, [Cu(MeCN)₄]ClO₄, [Cu(MeCN)₄]BF₄ and [Cu(MeCN)₄]PF₆ in presence of triphenylphosphine as a coligand. Complexes 1–4 were then characterized by elemental analyses, FTIR, UV-visible and ¹H NMR spectroscopy. Mononuclear copper(I) complexes 1–4 were formed with L in its keto form by involvement of azomethine nitrogen and the carbonyl oxygen along with two PPh₃ groups. A single crystal X-ray diffraction study of the representative complex [(Cu(L)(PPh₃)₂]CIO₄ (2) reveals a distorted tetrahedral geometry around Cu(I). Crystal data of (2): space group = C2/c, a = 42.8596 (9) Å, b = 14.6207 (3) Å, c = 36.4643 (7) Å, V = 20,653.7 (7) ų, Z = 16. Complexes 1–4 exhibit quasireversible redox behaviour corresponding to a Cu(I)/Cu(II) couple. All complexes show blue-green emission as a result of fluorescence from an intra-ligand charge transition (ILCT), ligand to ligand charge transfer transition (LLCT) or mixture of both. Significant increase in size of the counter anion shows marked effect on quantum efficiency and lifetime of the complexes in solution.     

Separation of molybdenum (VI) by extraction withn-octylaniline from hydrochloric acid medium

n-Octylaniline in bezene was used for the extractive separation of molybdenum (VI) from hydrochloric acid medium. Molybdenum(VI) was extracted quantitatively from 10 ml aqueous solution 1.5M in hydrochloric acid and 10M in lithium chloride into 10 ml of 10%n-octylaninline in benzene. It was stripped from the organic phase with 5% aqueous ammonia solution and estimated spectrophotometrically with thiocyanate at 465 nm. The interference of various ions has been studied in detail and conditions have been established for the determination of molybdenum(VI) in synthetic mixtures and alloy samples.     

Sulfonylureas as Dual Acting Agents — Synthesis and Biological Activity

2‐Amino‐5‐aryl/alkyl‐1,3,4‐thiadiazoles 3a‐e were used as intermediates in the synthesis of some 1,3‐substituted urea derivatives 5a‐o to evaluate their antidiabetic activity as well as antibacterial activity. The obtained compounds exhibited marginal activity against the animal models and the selected microorganisms.     

Cobalt(II)‐based Metalloradical Activation of 2‐(Diazomethyl)pyridines for Radical Transannulation and Cyclopropanation

A new catalytic method for the denitrogenative transannulation/cyclopropanation of in‐situ‐generated 2‐(diazomethyl)pyridines is described using a cobalt‐catalyzed radical‐activation mechanism. The method takes advantage of the inherent properties of a Co^III‐carbene radical intermediate and is the first report of denitrogenative transannulation/cyclopropanation by a radical‐activation mechanism, which is supported by various control experiments. The synthetic benefits of the metalloradical approach are showcased with a short total synthesis of (±)‐monomorine.     

In memory of Prof. Venkataraman: Recent advances in the synthetic methodologies of flavones

Flavones are present in a variety of medicines and natural products and are important structural motif due to their unique mode of physiological action. Hence the structural importance of flavone moiety has elicited a great deal of interest in the field of organic synthesis and chemical biology to develop some new and improved synthesis of this molecular skeleton. Herein, we have described an up to date overview on the recent advances in the diverse synthetic methodologies of flavones. The review covers the basic conceptual and practical catalytic synthesis like carbonylative annulation, cyclodehydration, Suzuki Miyaura coupling, Heck coupling, green methodologies, metal catalyzed reactions, organocatalytic transformations, microwave irradiation, etc. which are significant for constructing flavone skeleton. This review will satisfy the expectations of readers who are interested in the development of the field and looking for an update. It will stimulate researchers to develop new and creative synthetic access to this heterocyclic system, which will be instrumental in the advancement of flavone chemistry.     

Extraction Behaviour of Cyanex‐923 and Cyanex‐471X Towards the Rhodium(III) from Bromide Media and Its Separation from other Platinum Metals

The extraction of Rh(III) from bromide media with Cyanex‐923 and Cyanex‐471X in toluene was studied. The quantitative extraction of Rh(III) with extractants was found by studying the different parameters like, hydrobromic acid concentration, extractant concentration, diluents and effect of temperature on extraction. The optimum condition was [HBr] = 1.0–1.5 moll^?1, [SnCl₂] = 0.2 moll^?1 with [Cyanex‐923] = 0.15 moll^?1, while it was [HBr] = 1.5–2.0 moll^?1, [SnCl₂] = 0.4 moll^?1 with [Cyanex‐471X] = 0.8 moll^?1 in toluene. The quantitative extraction was observed only in the presence of SnCl₂ for both extractants. The complete recovery of Rh(III) from the Cyanex‐923 extracted organic phase was observed with the 1:1 mixture of (4.0 moll^?1 HCl + 2.0 moll^?1 HNO₃), and that with the Cyanex‐471X extracted organic phase was found with 1:1 mixture of (2.0 moll^?1 H₂SO₄ + 1.0 moll^?1 KMnO₄). Stoichiometric ratio of Rh(III) with both extractants was 1:1. The proposed methods were employed for extraction and separation of Rh(III) from other platinum metal ions and also for recovery of Rh(III) from a synthetic solution of spent autocatalysts.     

Liquid-liquid extraction of palladium(II) with N-n-octylaniline from hydrochloric acid media

N-n-Octylaniline in xylene is used for the extractive separation of palladium(II) from hydrochloric acid medium. Palladium(II) was extracted quantitatively with 10 ml of 2% reagent in xylene from 0.5-2 M hydrochloric acid medium. It was stripped from the organic phase with 1:1 ammonia and estimated spectrophotometrically with pyrimidine-2-thiol at 420 nm. The effects of metal ion, acids, reagent concentration and of various foreign ions have been investigated. The method affords binary separation of palladium(II) from iron(III), cobalt(II), nickel(II) and copper(II) and is applicable to the analysis of synthetic mixtures and alloys. The method is fast, accurate and precise.