A catalytic system for intermolecular benzylic C(sp3)–H amination is developed utilizing 1,2,3,4-tetrazole as a nitrene precursor via iron catalysis. This method enables direct installation of ...2-aminopyridine into the benzylic and heterobenzylic position. The method selectively aminates 2° benzylic C(sp3)–H bond over the 3° and 1° benzylic C(sp3)–H bonds. Experimental studies reveal that the C(sp3)–H amination undergoes via the formation of a benzylic radical intermediate. This study reports the discovery of new method for 2-pyridine substituted benzylamine synthesis using inexpensive, biocompatible base metal catalysis that should have wide application in the context of medicinal chemistry and drug discovery.
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•Iron catalysis for CN bond formation.•Iron-porphyrin catalysis.•Iron catalysis for C(sp2)–H & C(sp3)–H activation & CN bond formation.•Iron catalysis for high-valued ...N-heterocycles/molecules.•Metalloradical catalysis by iron-porphyrin catalysis.•Denitrogenative transformation of tetrazoles by iron catalysis.
Direct CN bond forming reaction by utilizing the non-precious transition metals is an attractive field of research in organic synthesis. Unlike the conventional use of precious metals like rhodium, palladium, ruthenium, and iridium that are commonly used in these reactions, the use of non-precious metals, particularly those are non-toxic and high abundant, holds distinct attention owing to the increasing demand of sustainable chemical processes. Among them, iron catalysis offers notable advantages for sustainable chemical synthesis. Iron-catalysed nitrene transfer reactions have emerged as robust and eco-friendly methods for constructing various valuable CN bonds. In this review, we provide a comprehensive overview of the advancements in iron catalysis for the nitrene transfer reactions aimed at synthesizing diverse CN bonds.
A concept for intermolecular C–N cross-coupling amination has been discovered using tetrazoles and aromatic and aliphatic azides with boronic acids under iron-catalyzed conditions. The amination ...follows an unprecedented metalloradical activation mechanism that is different from traditional metal-catalyzed C–N cross-coupling reactions. The scope of the reaction has been demonstrated by the employment of a large number of tetrazoles, azides, and boronic acids. Moreover, several late-stage aminations and a short synthesis of a drug candidate have been showcased for further synthetic utility. Collectively, this iron-catalyzed C–N cross-coupling should have wide applications in the context of medicinal chemistry, drug discovery, and pharmaceutical industries.
Bis-azoaromatic electron traps, viz. 2-(2-pyridylazo)azoarene 1, have been synthesized by colligating electron-deficient pyridine and azoarene moieties, and they act as apposite proradical templates ...for the formation of stable open-shell diradical complexes (1 •–)RhIII(1 •–)+ (2+), starting from the low-valent electron reservoir RhI. The less stable monoradical RhIII(1 •–)Cl2(PPh3)3 (3) has also been isolated as a minor product. These π-radical complexes are multiredox systems, and the electron transfer processes occur exclusively within the pincer-type NNN ligand backbone 1. Molecular and electronic structures of the diradicals and monoradicals have been ascertained with the aid of X-ray diffraction, electrochemical, spectroelectrochemical, and spectral (electronic, IR, NMR, and EPR) studies. In the diradicals 2+, the orthogonal disposition of two ligand π orbitals linked via a closed-shell metal center (t2 6) impedes significant coupling between the radicals. Indeed, the observed magnetic moment of 2a + lies near ∼2.3 μB over the temperature range 50–300 K. A very weak antiferromagnetic (AF) intramolecular spin–spin interaction between two ligand π arrays in (1 •–)RhIII(1 •–)+ have been found experimentally (J ≈ −5 cm–1), and this is further substantiated by density functional theory (DFT) calculations at the (U)B3LYP/6-31G(d,p) level.
Sphaerospora molnari is a myxozoan parasite causing skin and gill sphaerosporosis in common carp (Cyprinus carpio) in central Europe. For most myxozoans, little is known about the early development ...and the expansion of the infection in the fish host, prior to spore formation. A major reason for this lack of information is the absence of laboratory model organisms, whose life-cycle stages are available throughout the year.
We have established a laboratory infection model for early proliferative stages of myxozoans, based on separation and intraperitoneal injection of motile and dividing S. molnari stages isolated from the blood of carp. In the present study we characterize the kinetics of the presporogonic development of S. molnari, while analyzing cellular host responses, cytokine and systemic immunoglobulin expression, over a 63-day period. Our study shows activation of innate immune responses followed by B cell-mediated immune responses. We observed rapid parasite efflux from the peritoneal cavity (< 40 hours), an initial covert infection period with a moderate proinflammatory response for about 1-2 weeks, followed by a period of parasite multiplication in the blood which peaked at 28 days post-infection (dpi) and was associated with a massive lymphocyte response. Our data further revealed a switch to a massive anti-inflammatory response (up to 1456-fold expression of il-10), a strong increase in the expression of IgM transcripts and increased number of IgM
B lymphocytes, which produce specific antibodies for the elimination of most of the parasites from the fish at 35 dpi. However, despite the presence of these antibodies, S. molnari invades the liver 42 dpi, where an increase in parasite cell number and indistinguishable outer cell membranes are indicative of effective exploitation and disguise mechanisms. From 49 dpi onwards, the acute infection changes to a chronic one, with low parasite numbers remaining in the fish.
To our knowledge, this is the first time myxozoan early development and immune modulation mechanisms have been analyzed along with innate and adaptive immune responses of its fish host, in a controlled laboratory system. Our study adds important information on host-parasite interaction and co-evolutionary adaptation of early metazoans (Cnidaria) with basic vertebrate (fish) immune systems and the evolution of host adaptation and parasite immune evasion strategies.
Impairments in executive functions are common in neurogenetic disorders such as Huntington's disease (HD) and are thought to significantly influence the patient's functional status. Reliable tools ...with higher ecological validity that can assess and predict the impact of executive dysfunction in daily-life performance are needed. This study aimed to develop and validate a novel non-immersive virtual reality task ("EcoKitchen") created with the purpose of capturing cognitive and functional changes shown by HD carriers without clinical manifestations of the disease (Premanifest HD), in a more realistic setting.
We designed a virtual reality task with three blocks of increasing executive load. The performance of three groups (Controls, CTRL; Premanifest HD individuals, HP; Early Manifest HD patients, HD) was compared in four main components of the study protocol: the EcoKitchen; a subjective (self-report) measure - "The Adults and Older Adults Functional Assessment Inventory (IAFAI)"; the "Behavioural Assessment of Dysexecutive Syndrome battery (BADS)"; and a conventional neuropsychological test battery. We also examined statistical associations between EcoKitchen and the other executive, functional and clinical measures used.
The HD group showed deficits in all the assessment methods used. In contrast, the HP group was only found to be impaired in the EcoKitchen task, particularly in the most cognitively demanding blocks, where they showed a higher number of errors compared to the CTRL group. Statistically significant correlations were identified between the EcoKitchen, measures of the other assessment tools, and HD clinical features.
The EcoKitchen task, developed as an ecological executive function assessment tool, was found to be sensitive to early deficits in this domain. Critically, in premanifest HD individuals, it identifies dysfunction prior to symptom onset. Further it adds a potential tool for diagnosis and management of the patients' real-life problems.
Bilateral giant juvenile fibroadenoma of breasts Mukhopadhyay, Madhumita; Patra, Rishavdeb; Mondal, Sima ...
Journal of Indian Association of Pediatric Surgeons,
04/2009, Letnik:
14, Številka:
2
Journal Article
Recenzirano
Odprti dostop
An 11-year-old girl with rapidly enlarging bilateral breast lumps is reported. It was diagnosed as a case of juvenile fibroadenoma following fine needle aspiration cytology and confirmed on ...histopathological examination of the excised specimens.
A prospective randomised study of 200 women with spontaneous onset of labour was carried out in 100 women who were given 40mg of drotaverine hydrochloride intravenously at > or = 3cm dilatation of ...the cervix, the other 100 were taken as control. The effects of the drug on the progress and outcome of labour were noted. The mean durations of active phase of labour in primigravida and multigravida were 148.9 minutes and 99.5 minutes in drotaverine group whereas in control group were 331.6 minutes and 227.9 minutes respectively. It was concluded that drotaverine is highly effective in reducing the duration of active phase of labour by hastening cervical dilatation, more effective when given in more dilated cervix than with less dilatation and more effective in multigravida than in primigravida. There was no interference with uterine contractility and no increase in operative delivery. It reduces the incidence of traumatic postpartum haemorrhage by reducing the incidence of cervical tear. It is a safe drug for the mother as well as for the baby.
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