Search results for "Pyrrole"

X-ray structure determination of a metastable state of carbonmonoxy myoglobin after photodissociation.

1996

The x-ray structure of carbon monoxide (CO)-ligated myoglobin illuminated during data collection by a laser diode at the wavelength lambda = 690 nm has been determined to a resolution of 1.7 A at T = 36 K. For comparison, we also measured data sets of deoxymyoglobin and CO-ligated myoglobin. In the photon-induced structure the electron density associated with the CO ligand can be described by a tube extending from the iron into the heme pocket over more than 4 A. This density can be interpreted by two discrete positions of the CO molecule. One is close to the heme iron and can be identified to be bound CO. In the second, the CO is dissociated from the heme iron and lies on top of pyrrole ri…

Crystal structure of meso-tetrakis(4-nitrophenyl)porphyrin nitrobenzene disolvate

2014

The porphyrin core of the title centrosymmetric compound, C44H26N8O8·2C6H5NO2, is approximately planar, the maximum deviation being 0.069 (3) Å. The planes of the benzene rings of the nitrophenyl substituents are almost perpendicular to the porphyrin mean plane, making dihedral angles of 73.89 (9) and 89.24 (9)°. The two pyrrole ring H atoms are equally disordered over the four pyrrole ring N atoms. In the crystal, weak C—H...O and C—H...N hydrogen bonds link the porphyrin molecules into a three-dimensional supramolecular network. The nitrobenzene solvent molecules are linked by weak C—H...O hydrogen bonds into supramolecular chains propagating along thea-axis direction.

Structural Approaches to Explain the Selectivity of COX-2 Inhibitors: Is There a Common Pharmacophore?

2000

The identification and characterisation of the isoenzyme cyclooxygenase 2 (COX-2) stimulated investigations to develop efficient non-steroidal anti-inflammatory drugs with reduced side effects compared to standard NSAIDs. This review will focus on the structural features needed to achieve COX-2 selectivity. Five structural classes can be identified together with a class bearing little or no resemblance to one another in their molecular structure. The most interesting point is the very distinct structure/activity relationship. On the one hand only minor modifications to a particular compound induce a drastic change in its COX selectivity and on the other hand the structural prerequisites in …

Poster Presentation

2009

Photoassisted Mineralization of Aromatic and Aliphatic N Heterocycles in Aqueous Titanium Dioxide Suspensions and the Fate of the Nitrogen Heteroatoms

2008

Abstract The photoassisted degradation of aromatic heterocycles (pyrrole, imidazole, pyrazole, isoxazole, oxazole and thiazole) and N-containing alicycles (aliphatic heterocycles: pyrrolidine, 4-butanelactam and 5-pentanelactam) was examined in liquid–solid dispersions. Complete mineralization (TOC) of the aromatic heterocycles was attained within ca. 1 h of UV irradiation of the TiO 2 /heterocycle system in acidic (pH 3), near-neutral (pH 6.0–7.6) and alkaline (pH 11) media. Mineralization kinetics were, in general, not appreciably influenced by the presence of acid but tended to be somewhat slower in alkaline media. N-alicycles were photomineralized more slowly than were the aromatics. Th…

Synthesis of a new class of pyrrolo[3,4-h]quinazolines with antimitotic activity

2014

Abstract A new series of pyrrolo[3,4- h ]quinazolines was conveniently prepared with a broad substitution pattern. A large number of derivatives was obtained and the cellular cytotoxicity was evaluated in vitro against 5 different human tumor cell lines with GI 50 values reaching the low micromolar level (1.3–19.8 μM). These compounds were able to induce cell death mainly by apoptosis through a mitochondrial dependent pathway. Selected compounds showed antimitotic activity and a reduction of tubulin polymerization in a concentration-dependent manner. Moreover, they showed anti-angiogenic properties since reduced in vitro endothelial cell migration and disrupted HUVEC capillary-like tube net…

One-Pot Synthesis of Pyrrole-2-carboxylates and -carboxamides via an Electrocyclization/Oxidation Sequence

2014

An electrocyclic ring closure is the key step of an efficient one-pot method for the synthesis of pyrrole-2-carboxylates and -carboxamides from chalcones and glycine esters or amides. The 3,4-dihydro-2H-pyrrole intermediates generated in situ are oxidized to the corresponding pyrroles by stoichiometric oxidants or by catalytic copper(II) and air in moderate to high yields. A wide range of functional groups are tolerated, and further combination with an in situ bromination gives access to polyfunctional pyrrole scaffolds.

One-stage periodical anodic-cathodic double pulse deposition of nanocomposite materials. Application to Prussian Blue/polypyrrole film coated electro…

2014

Abstract Novel electrochemical method of one-stage deposition of composite films on electrode surface has been proposed. The procedure includes a periodical series of potentiostatic or galvanostatic pulses of alternative polarity imposed at electrode in contact with a mixture of two solute precursors, one of which is able to generate a solid phase under its electrooxidation while another one is transformed into another solid phase under its electroreduction. Parameters of anodic and cathodic pulses (potential or current, pulse duration) may be chosen independently from one another, their relation allows one to vary the relative contents of components in the deposited composite. Thickness of…

The Adult Sprague-Dawley Sugen-Hypoxia Rat Is Still "the One:" A Model of Group 1 Pulmonary Hypertension: Reply to Le Cras and Abman

2020

To the editor: Kojonazarov et al. recently reported severe emphysema in the SU5416/Hypoxia (SuHx) rat model of pulmonary hypertension (1). The authors found that adult male Wistar Kyoto (WKY) rats had increased air-to-tissue ratio as judged by non-gated in vivo micro-computed tomography (CT), and an increased mean linear intercept (MLI) as surrogate of emphysema (1, 2). Le Cras and Abman now responded to the Kojonazarov report by underlining the “important role of the developmental timing of disrupted VEGF signaling” (3). They cite earlier studies conducted on the ovine fetus showing that VEGF inhibition caused vascular remodeling, reduction in vascular/airway growth, and neonatal pulmonary…

Pharmaceutical potential of synthetic and natural pyrrolomycins

2015

The emergence of antibiotic resistance is currently considered one of the most important global health problem. The continuous onset of multidrug-resistant Gram-positive and Gram-negative bacterial strains limits the clinical efficacy of most of the marketed antibiotics. Therefore, there is an urgent need for new antibiotics. Pyrrolomycins are a class of biologically active compounds that exhibit a broad spectrum of biological activities, including antibacterial, antifungal, anthelmintic, antiproliferative, insecticidal, and acaricidal activities. In this review we focus on the antibacterial activity and antibiofilm activity of pyrrolomycins against Gram-positive and Gram-negative pathogens…