Synthesis of p-tert-Butylcalix[4] Arenes with Diester Bridge Spanning the 1,3-(Distal) Positions on the Lower Rim

Abstract

p-tert-Butylcalix[4]crown ether esters have been synthesized in good yield using two synthetic methods.     

Synthesis of New Macrocyclic Polyaza Compounds Containing 1-Methylpyrazole

New macrocyclic polyaza compoundscontaining the 1-methylpyrazole moiety are synthesizedin high yield by [2+2]dipodal condensation andreduction. The ring contracted structure of the Schiffbase has been elucidated by NMR. Two of thesemacrocycles form dinuclear complexes with copper andsilver. Macrocyclic Schiff base 5a extracts74.5% silver from aqueous to organic phase.     

Estimation of submarine groundwater discharge using radium mass-balance in Mumbai Harbour Bay,Mumbai, India

Journal of Radioanalytical and Nuclear Chemistry - The Mumbai Harbour Bay (MHB), Mumbai, India houses a large number of ports, industrial units and urban settlements thus the groundwater may be...     

Near-UV induced interstrand cross-links in anthraquinone-DNA duplexes

Anthraquinone (AQ) has been extensively used as a photosensitizer to study charge transfer in DNA. Near-UV photolysis of AQ induces electron abstraction in oligonucleotides leading to AQ radical anions and base radical cations. In general, this reaction is followed by the transport of base radical cations to sites of low oxidation potential, that is, GG, and conversion of G radical cations to DNA breaks. Here, we show that AQ also produces interstrand cross-links in DNA duplexes. About half of the cross-links collapse to single strands in hot piperidine treatment. The structure of stable interstrand cross-links was deduced by MS, NMR, and sequence substitution. The cross-links consist of a covalent link between the methyl group of T on one strand with either C6 or C7 of AQ on the other strand. The formation of interstrand cross-links decreased in O2 compared to deoxygenated solutions. In the presence of O2, the yield of breaks at GG doublets was 10-fold greater than that of cross-links for end tethered AQ, while cross-links exceeded breaks for centrally located AQ. The formation of stable cross-links can be explained by initial charge transfer from T to excited AQ, deprotonation of T radical cations, and condensation of the latter species with AQ radicals. These studies reveal a novel pathway of damage in the photolysis of AQ-DNA duplexes.     

An inventory model for non-instantaneous deteriorating items with quadratic demand rate and shortages under trade credit policy

noindent In this paper, we propose an appropriate inventory model for non-instantaneous deteriorating items over quadratic demand rate with permissible delay in payments and time dependent deterioration rate. In this model, the completely backlogged shortages are allowed. In several existing results, the authors discussed that the deterioration rate is constant in each cycle. However, the deterioration rate of items are not constant in real world applications. Motivated by this fact, we consider that the items are deteriorated with respect to time. To minimize the total relevant inventory cost, we prove some useful theorems to illustrate the optimal solutions by finding an optimal cycle time with the necessary and enough conditions for the existence and uniqueness of the optimal solutions. Finally, we discuss the numerical instance and sensitivity of the proposed model.     

Determination of aromatic primary amines at microg l(-1) level in environmental waters by gas chromatography-mass spectrometry involving N-allyl-n'-arylthiourea formation and their on-line pyrolysis to aryl isothiocyanates

Derivatization of aromatic primary amines to N-allyl-N'-arylthioureas by reaction with allyl isothiocyanate and GC-MS of the derivatives, when pyrolysis to aryl isothiocyanates occurs in the heated injector, has been used to determine aromatic amines in the range 0.5-50 microg l(-1) with a correlation coefficient, r, in the range 0.9902-0.9992. The limit of detection ranged 8 to 30 ng l(-1) when 60 ml of sample were preconcentrated, after derivatization, on a styrene-divinylbenzene copolymer sorbent. The pyrolytic cleavage of sym- and unsym-diaryl or alkyl-/arylthioureas has been rationalized. The chromatography of isothiocyanates is much superior to that of aryl amines and the specific mass fragmentation permits positive identification of amines. The method has been applied to spiked drinking water, groundwater and river water samples, when the recovery ranged from 84 to 109% with RSD of 5-9%, and to detect aromatic amines formed by reductive cleavage of azo dyes in effluents when the recovery of amine was in the range 81-95% with RSD 8-15%. The method is not applicable to nitroanilines.     

X-ray crystal and molecular structure of upper rim monoformylated calix[4]arene system

Selective formylation under controlled conditions leads to the formation of a monoformylated compound 11-formyl-25,27-bis(ethoxycarbonylmethoxy)-calix[4]arene (1). The spectroscopic results indicated that the calix[4]arene is present in a cone conformation. The crystal and molecular structure of (1) has been determined by X-ray diffraction methods. The crystal data are monoclinic, space group P2 ₁/c, M= 624.66, a= 10.341(1), b=15.176(1), c= 20.121(1) Å, = 91.90°(1), V= 3156.0(4) ų, Z= 4, D _c = 1.315 g cm^–3. The structure confirms the cone conformation for the molecule in the solid state as well.     

Design,synthesis, in silico and in vitro evaluation of novel diphenyl ether derivatives as potential antitubercular agents

Molecular Diversity - Diphenyl ether derivatives inhibit mycobacterial cell wall synthesis by inhibiting an enzyme, enoyl-acyl carrier protein reductase (InhA), which catalyses the last step in the...     

Use of Immunofluorescence and Confocal Laser Scanning Microscopy in Identifying Rare Cases of Anti-Neutrophil Cytoplasmic Antibodies (ANCA) Showing Dual Specificities to Myeloperoxidase and Proteinase3

Anti-neutrophil cytoplasmic antibodies (ANCA) are the immunodiagnostic markers for idiopathic necrotizing crescentic glomerulonephritis affecting mainly medium to small sized blood vessels. The diagnosis of ANCA associated vasculitis (AAV) is mainly based on clinical and histopathological characteristics along with the serological evidence. Immunofluorescence microscopy (IIF) is considered as the "gold standard" for ANCA detection, and ANCA showing two major patterns ie, cytoplasmic (c-ANCA) and perinuclear (p-ANCA) react with different antigenic targets of neutrophils like Proteinase3 (PR3) and Myeloperoxidase (MPO). A third unusual and rare immunofluorescence pattern called as "X- ANCA" or atypical ANCA is also sometimes seen. The difficulty in identification of ANCA immunofluorescence patterns is mainly seen due to the rare dual patterns seen in the same sera and also the additional nuclear immunofluorescence seen due to presence of anti-nuclear antibodies. ANCA testing by immunofluorescence and Confocal Laser scanning microscopy, as well as by specific ELISAs for detection of anti-PR3 and anti-MPO antibodies have helped in improving the diagnosis. Patients having dual specificities to MPO and PR3 in a patient is a rare finding. Among 425 clinically and histopathologically proven cases of AAV, eight patients (1.9%) had dual specificities, of which five patients showed mixed immunofluorescence pattern and 3 patients showed X-ANCA pattern which was confirmed by both immunofluorescence and Confocal Laser scanning microscopy and the dual specificities to MPO and PR3 were detected by individual ELISAs.