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1.
J Org Chem ; 88(2): 771-787, 2023 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-36577023

RESUMEN

We report a sustainable and eco-friendly approach for selective N-alkylation of various amines by alcohols, catalyzed by a well-defined Zn(II)-catalyst, Zn(La)Cl2 (1a), bearing a tridentate arylazo scaffold. A total of 57 N-alkylated amines were prepared in good to excellent yields, out of which 17 examples are new. The Zn(II)-catalyst shows wide functional group tolerance, is compatible with the synthesis of dialkylated amines via double N-alkylation of diamines, and produces the precursors in high yields for the marketed drugs tripelennamine and thonzonium bromide in gram-scale reactions. Control reactions and DFT studies indicate that electron transfer events occur at the azo-chromophore throughout the catalytic process, which shuttles between neutral azo, one-electron reduced azo-anion radical, and two-electron reduced hydrazo forms acting both as electron and hydrogen reservoir, enabling the Zn(II)-catalyst for N-alkylation reaction.

2.
Phys Chem Chem Phys ; 25(16): 11429-11441, 2023 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-37022088

RESUMEN

The electrochemical kinetics of the electrode material plays a crucial role in the development of various energy storage devices such as batteries, supercapacitors, and hybrid supercapacitors. Battery-type hybrid supercapacitors are envisaged as excellent candidates to bridge the performance gap between supercapacitors and batteries. Due to its open pore framework structure and more structural stability, porous cerium oxalate decahydrate (Ce2(C2O4)3·10H2O) is found here to be a potential energy storage material partly because of the presence of planer oxalate anions (C2O42-). Superior specific capacitance equivalent to 78 mA h g-1 (capacitance: 401 F g-1) at 1 A g-1 in the potential window of -0.3 to 0.5 V was observed in an aqueous 2 M KOH electrolyte. The predominant pseudocapacitance mechanism seems to operate because of the high charge storage capacity of the electrode as intercalative (diffusion control) and surface control charges stored by the porous anhydrous Ce2(C2O4)3·10H2O, which were close to 48% and 52%, respectively, at a 10 mV s-1 scan rate. Further, in the full cell asymmetric supercapacitor (ASC) mode in which porous Ce2(C2O4)3·10H2O is the positive electrode and activated carbon (AC) is the negative electrode, at the operating potential window of 1.5 V, the highest specific energy of 96.5 W h kg-1 and a specific power of ∼750 W kg-1 at 1 A g-1 current rate and a high power density of 1453 W kg-1, the hybrid supercapacitor still attains an energy density of 10.58 W h kg-1 at a 10 A g-1 current rate, which was obtained with a high cyclic stability. The detailed electrochemical studies confirm a high cyclic stability and a superior electrochemical charge storage property of porous Ce2(C2O4)3·10H2O making it a potential pseudocapacitive electrode for use in large energy storage applications.

3.
J Am Chem Soc ; 144(44): 20442-20451, 2022 Nov 09.
Artículo en Inglés | MEDLINE | ID: mdl-36282681

RESUMEN

Herein we report a ligand-centered redox-controlled strategy for the synthesis of an unusual binuclear diradical cobalt(III) complex, [Co2III(L•3-)2] (1), featuring two three-electron reduced trianionic monoradical 2,9-bis(phenyldiazo)-1,10-phenanthroline ligands (L•3-) and two intermediate-spin cobalt(III) centers having a Co-Co bond. Controlled ligand-centered oxidation of 1 afforded two mononuclear complexes, [CoII(L•-)(L0)]+ ([3])+ and [CoII(L0)2]2+ ([2]2+), which upon further ligand-centered reduction yielded a di-azo-anion diradical complex, [CoII(L•-)2] (4). In complex 1, two three-electron reduced di-azo-anion monoradical ligands (L•3-) bridge two intermediate Co(III) centers at a distance of 2.387(2) Å, while upon oxidation, one of the coordinating azo-arms of L becomes pendent, and in complexes [2]2+, [3]+, and 4, two tetradentate ligands coordinate a single Co(II) center in a tridentate meridional fashion with one uncoordinated azo-arm from each of the ligands. In the presence of reducing agents, the monomers [2]2+, [3]+, and 4 undergo ligand-centered reduction to form azo-anion radicals, and the otherwise pendent azo-arms in the presence of cobalt(II)-salts like Co(ClO4)2 or CoCl2 bind the second Co(II)-ion; further internal electron transfer from the cobalt center to the arylazo backbone produces the binuclear complex 1. Spectroscopic analysis, DFT studies, and control experiments were performed to understand the electronic structures and the ligand-centered redox-controlled interconversion. The application of complex 1 as a molecular memory device (memristor) was also explored. Complex 1 showed encouraging results as a memristor with a current ON/OFF ratio > 104 and is highly promising for resistive RAM/ROM applications.

4.
J Org Chem ; 87(11): 7106-7123, 2022 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-35583483

RESUMEN

Herein, we report the synthesis and characterization of two ruthenium-based pincer-type catalysts, [1]X (X = Cl, PF6) and 2, containing two different tridentate pincer ligands, 2-pyrazolyl-(1,10-phenanthroline) (L1) and 2-arylazo-(1,10-phenanthroline) (L2a/2b, L2a = 2-(phenyldiazenyl)-1,10-phenanthroline; L2b = 2-((4-chlorophenyl)diazenyl)-1,10-phenanthroline), and their application in the synthesis of substituted pyrroles via dehydrogenative alcohol functionalization reactions. In catalyst [1]X (X = Cl, PF6), the tridentate scaffold 2-pyrazolyl-(1,10-phenanthroline) (L1) is apparently redox innocent, and all the redox events occur at the metal center, and the coordinated ligands remain as spectators. In contrast, in catalysts 2a and 2b, the coordinated azo-aromatic scaffolds are highly redox-active and known to participate actively during the dehydrogenation of alcohols. A comparison between the catalytic activities of these two catalysts was made, starting from the simple dehydrogenation of alcohols to further dehydrogenative functionalization of alcohols to various substituted pyrroles to understand the advantages/disadvantages of the metal-ligand cooperative approach. Various substituted pyrroles were prepared via dehydrogenative coupling of secondary alcohols and amino alcohols, and the N-substituted pyrroles were synthesized via dehydrogenative coupling of aromatic amines with cis-2-butene-1,4-diol and 2-butyne-1,4-diol, respectively. Several control reactions and spectroscopic experiments were performed to characterize the catalysts and establish the reaction mechanism.

5.
J Org Chem ; 87(5): 2921-2934, 2022 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-35099947

RESUMEN

Herein, we describe a metal-ligand cooperative approach for the sustainable synthesis of various aldazines, ketazines, and N-acylhydrazones via dehydrogenative functionalization of alcohols with hydrazine hydrate using a simple, easy-to-prepare iron catalyst featuring a redox noninnocent tridentate arylazo backbone. Our catalyst is compatible with both primary and secondary alcohols to produce a wide variety of substituted aldazines, ketazines, and N-acylhydrazones in good isolated yields in air. A series of control experiments are performed to elucidate the reaction mechanism.

6.
Org Biomol Chem ; 20(2): 296-328, 2022 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-34904619

RESUMEN

Catalysis offers a straightforward route to prepare various value-added molecules starting from readily available raw materials. The catalytic reactions mostly involve multi-electron transformations. Hence, compared to the inexpensive and readily available 3d-metals, the 4d and 5d-transition metals get an extra advantage for performing multi-electron catalytic reactions as the heavier transition metals prefer two-electron redox events. However, for sustainable development, these expensive and scarce heavy metal-based catalysts need to be replaced by inexpensive, environmentally benign, and economically affordable 3d-metal catalysts. In this regard, a metal-ligand cooperative approach involving transition metal complexes of redox noninnocent ligands offers an attractive alternative. The synergistic participation of redox-active ligands during electron transfer events allows multi-electron transformations using 3d-metal catalysts and allows interesting chemical transformations using 4d and 5d-metals as well. Herein we summarize an up-to-date literature report on the metal-ligand cooperative approaches using transition metal complexes of redox noninnocent ligands as catalysts for a few selected types of catalytic reactions.

7.
Org Biomol Chem ; 20(15): 3105-3117, 2022 04 13.
Artículo en Inglés | MEDLINE | ID: mdl-35088804

RESUMEN

Herein, we report ligand-centered redox controlled Zn(II)-catalyzed multicomponent approaches for synthesizing pyrimidines and triazines. Taking advantage of the ligand-centered redox events and using a well-defined Zn(II)-catalyst (1a) bearing (E)-2-((4-chlorophenyl)diazenyl)-1,10-phenanthroline (L1a) as the redox-active ligand, a wide variety of substituted pyrimidines and triazines were prepared via dehydrogenative alcohol functionalization reactions. Pyrimidines were prepared via two pathways: (i) dehydrogenative coupling of primary and secondary alcohols with amidines and (ii) dehydrogenative coupling of primary alcohols with alkynes and amidines. Triazines were prepared via dehydrogenative coupling of alcohols and amidines. Catalyst 1a is well tolerant to a wide range of substrates yielding the desired pyrimidines and triazines in moderate to good isolated yields. A series of control reactions were performed to predict the plausible mechanism, suggesting that the active participation of the ligand-centered redox events enables the Zn(II)-complex 1a to act as an efficient catalyst for synthesizing these N-heterocycles. Electron transfer processes occur at the azo-aromatic ligand throughout the catalytic reaction, and the Zn(II)-center serves only as a template.


Asunto(s)
Triazinas , Zinc , Alcoholes , Amidinas , Aniones , Catálisis , Ligandos , Oxidación-Reducción , Pirimidinas
8.
Phys Chem Chem Phys ; 24(46): 28584-28598, 2022 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-36412503

RESUMEN

The as-prepared La1-xKxCoO3-δ (0 ≤ x ≤ 0.5) showed superior pseudocapacitive charge storage capacity in a neutral 0.5 M Na2SO4 electrolyte and superior electrocatalytic activities for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) in a 1 M KOH electrolyte. 30% K doped p-type La0.7K0.3CoO3-δ presents superior OER activity with an overpotential of ∼335 mV at 10 mA cm-2 current rate in a 1 M KOH electrolyte. Additionally, La1-xKxCoO3-δ (0 ≤ x ≤ 0.5) presents an excellent charge-storage capacitance in a neutral 0.5 M Na2SO4 electrolyte resulting in a gravimetric capacitance of the La0.5K0.5CoO3-δ electrode equivalent to 378 F g-1, 282 F g-1, 221 F g-1, 163 F g-1, and 74 F g-1 at a current density of 1 A g-1, 2 A g-1, 3 A g-1, 5 A g-1, and 10 A g-1, respectively. After 2500 continuous cycles of charge/discharge, the La0.5K0.5CoO3-δ//AC cell exhibits higher stability, capacitive retention (94%) and coulombic efficiency (97%). The gravimetric charge storage capacity of ASCs (La0.5K0.5CoO3-δ//AC) in the full cell mode showed capacitance equivalent to 308 F g-1, 287 F g-1, 238 F g-1, 209 F g-1 and 162 F g-1 at current densities of 1 A g-1, 2 A g-1, 3 A g-1, 5 A g-1 and 10 A g-1 in a neutral 0.5 M Na2SO4 electrolyte respectively. Maximum specific power equivalent to ∼6884 W kg-1 was observed at a current density of 10 A g-1 when the specific energy reached ∼57 W h kg-1 for the full cell. The double exchange mechanism coupled with stoichiometric oxygen defects present in the perovskite lattice seems to be operative behind the enhanced electrocatalytic OER properties, and additionally, it improves the charge storage kinetics of the La1-xKxCoO3-δ (0 ≤ x ≤ 0.5) electrode in a neutral Na2SO4 electrolyte for supercapacitor application. This work presents a rational strategy for introducing facile oxygen ion defects into perovskite structured La1-xKxCoO3-δ (0 ≤ x ≤ 0.5) to develop multifunctional electrode materials for a supercapacitor and energy conversion (OER/ORR) electrode of metal-air batteries.

9.
Phys Chem Chem Phys ; 25(1): 326-340, 2022 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-36477306

RESUMEN

Grid-scale bulk energy storage solutions are needed to utilize the full potential of renewable energy technologies. Pseudocapacitive electrochemical energy storage can play a vital role in developing efficient energy storage solutions. The use of perovskites as anion intercalation-type pseudocapacitor electrodes has received significant attention in recent years. In this study, Sr-doped YMnO3i.e. Y1-xSrxMnO3-δ perovskite was prepared by the solid-state ceramic route and studied for electrochemical pseudocapacitance in aqueous KOH electrolyte. Microstructures, morphologies, and electrochemical properties of these materials were investigated through X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance method. The formation of the mostly cubic phase, with 50% strontium doped YMnO3 (YSMO-50) provides an equivalent three-dimensional network and superior conductivity due to Mn3+-O2--Mn4+ hopping conduction. YSMO-50 exhibited low intrinsic resistance, 1.45 Ω cm-2, and the highest specific capacity, 259.83 F g-1 at a current density of 1 A g-1 in 2 M KOH aqueous electrolyte. Redox-mediated interconversion of oxide to hydroxide (M2+O2- + H2O + e- ↔ M+OH- + OH-) in aqueous media is shown to be the reason behind the high capacitance of YSMO-50. The excellent electrochemical performance of YSMOs was attributed to the reversible interconversion of oxide-ion into hydroxide ion coupled with surface redox reaction of Mn2+/Mn3+ and Mn3+/Mn4+ occurring during the charge-discharge process. The maximum energy density of 65.13 W h kg-1 was achieved at a power density of 0.45 kW kg-1 for an asymmetric mode, in which YSMO serves as a negative electrode and Activated carbon (AC) as a positive electrode in the PVA-KOH gel electrolyte. Our study reveals that the doping of low valence atom (Sr) at the A-site in perovskite manganites (YMnO3) may be an effective tool to enhance the pseudocapacitive performance of perovskite-based electrodes.

10.
Phys Chem Chem Phys ; 25(1): 555-569, 2022 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-36484154

RESUMEN

Currently, enhancing the performance of electrochemical supercapacitors is the subject of intense research to fulfill the ever-increasing demand for grid-scale energy storage and delivery solution, thereby utilizing the full potential of renewable energy resources and decreasing our dependence on fossil fuels. Metal sulfides, such as cobalt sulfide (CoS), nickel sulfide (NiS), molybdenum sulfide (MoS), copper sulfide (CuS), and others, have recently emerged as a promising class of active electrode materials, alongside other supercapacitor electrode materials, due to their relatively high specific capacitance values and exceptional reversible redox reaction activities. The synthesis, characterizations, and electrochemical performances of single-phase nanocrystalline ß-NiS are presented here and the electrode based on this material shows a specific capacitance of 1578 F g-1 at 1 A g-1 from the galvanostatic discharge profile, whereas a capacitance of 1611 F g-1 at 1 mV s-1 was obtained through the CV curve in 2 M KOH aqueous electrolyte. Additionally, the electrode also performs well in neutral 0.5 M Na2SO4 electrolytes resulting in specific capacitance equivalent to 403 F g-1 at 1 mV s-1 scan rate. The high charge storage capacity of the material is due to the superior intercalative (inner) charge storage coupled with the surface (outer) charges stored by the ß-NiS electrode and was found to be 72% and 28%, respectively, in aqueous 2 M KOH electrolyte. This intercalative charge storage mechanism is also responsible for its excellent cycling stability. Additionally, we assembled aqueous asymmetric supercapacitors (ASCs) with activated carbon (AC) as the negative electrode and the ß-NiS electrode as the positive electrode. The combination of the ß-NiS electrode and AC with excellent cycling stability resulted in the highest specific energy equivalent to ∼163 W h kg-1 and a specific power of ∼507 W kg-1 at 1 A g-1 current rate.

11.
Phys Chem Chem Phys ; 24(18): 11066-11078, 2022 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-35471404

RESUMEN

Pseudocapacitors offer both high energy and high power, making them suitable for grid-scale electrochemical energy storage to harness renewable energy produced from sun, wind, and tides. To overcome performance degradation in terms of cycling fading and lower specific capacitance values at high charge/discharge rates of electrochemical pseudocapacitors based on transition-metal oxides, perovskite-structured SrFeO3-δ was envisaged as a negative electrode that harnesses the Fe4+/3+ and Fe3+/2+ redox couple to deliver superior performance. SrFeO3-δ offers high specific capacitances of ca. 733 F g-1 at a scan rate of 1 mV s-1 and ca. 743 F g-1 at a current density of 1 A g-1 and demonstrates excellent cyclic stability over 2500 repeated cycles with capacitance retention of >92%, achieving 94% coulombic efficiency. The good cycling stability is attributed to the inherent metallic electrical conductivity of SrFeO3-δ and the fortuitous tendency of the robust cation framework structure to accommodate flexible oxygen content. The surface capacitive and diffusion-controlled contributions for capacitance are about ∼30% and ∼70%, respectively, at peak current and a scan rate equivalent to 1 mV s-1. The higher capacitance and stable performance make SrFeO3-δ an economical and abundant pseudocapacitive electrode.

12.
J Trop Pediatr ; 68(2)2022 02 03.
Artículo en Inglés | MEDLINE | ID: mdl-35135012

RESUMEN

OBJECTIVES: We aimed to evaluate blood pressure (BP) in Indian children who had similar demographic characteristics but hailed from different altitudes. METHODS: BP of school going children, aged 5 to 12 years, at five different locations varying in altitude (near sea level: n = 425; 2000 feet: n = 244; 4000 feet: n = 248; 6000 feet: n = 242 and 8000 feet: n = 250) was measured in a mountainous district in Himalaya. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were recorded by aneroid sphygmomanometer in the sitting posture using a calibrated instrument and four trained resident doctors. The average of three readings was taken. RESULTS: Of the 1229 children whose data were analyzed, 50.4% were boys. SBP showed a progressive rise from 99.5 (4.00) mmHg [mean (standard deviation)] at near sea level to 106.7 (4.17) mmHg at 8000 feet. Similarly, DBP showed a rise from 60.1 (3.67) mmHg to 66.8 (4.58) mmHg over the same altitude range. Analysis of covariance for BP variation with altitude, with age as covariate, indicated a modest but statistically significant rise in both SBP and DBP with altitude. Higher BP values was noted among children residing at higher than at lower altitude (0.8% at sea level to 18.8% at 8000 feet). Correlations between SBP and DBP values and height and weight, though positive and significant at p < 0.01 level, were weak. CONCLUSIONS: These data will help in correct interpretation of BP readings in children residing at high altitude.


Asunto(s)
Altitud , Hipertensión , Presión Sanguínea/fisiología , Determinación de la Presión Sanguínea , Estatura , Niño , Preescolar , Humanos , Masculino
13.
J Org Chem ; 86(19): 13186-13197, 2021 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-34528802

RESUMEN

An iron-catalyzed sustainable, economically affordable, and eco-friendly synthetic protocol for the construction of various trisubstituted pyrimidines is described. A wide range of trisubstituted pyrimidines were prepared using a well-defined, easy to prepare, bench-stable, and phosphine-free iron catalyst featuring a redox-noninnocent tridentate arylazo pincer under comparatively mild aerobic conditions via dehydrogenative functionalization of alcohols with alkynes and amidines.

14.
Org Biomol Chem ; 19(33): 7217-7233, 2021 09 07.
Artículo en Inglés | MEDLINE | ID: mdl-34612344

RESUMEN

Herein we report nickel-catalyzed sustainable synthesis of a few chosen five-membered fused nitrogen heterocycles such as benzimidazole, purine, benzothiazole, and benzoxazole via acceptorless dehydrogenative functionalization of alcohols. Using a bench stable, easy to prepare, and inexpensive Ni(ii)-catalyst, [Ni(MeTAA)] (1a), featuring a tetraaza macrocyclic ligand (tetramethyltetraaza[14]annulene (MeTAA)), a wide variety of polysubstituted benzimidazole, purine, benzothiazole, and benzoxazole derivatives were prepared via dehydrogenative coupling of alcohols with 1,2-diaminobenzene, 4,5-diaminopyrimidine, 2-aminothiphenol, and 2-aminophenol, respectively. A wide array of benzimidazoles were also prepared via a borrowing hydrogen approach involving alcohols as hydrogen donors and 2-nitroanilines as hydrogen acceptors. A few control experiments were performed to understand the reaction mechanism.

15.
J Trop Pediatr ; 67(4)2021 08 27.
Artículo en Inglés | MEDLINE | ID: mdl-34478546

RESUMEN

BACKGROUND AND OBJECTIVES: Assessing the co-infections with COVID-19 is crucial to delineate its true clinical impact. Pediatric information in this aspect is limited. Our study aims to analyze the spectrum of co-infections in pediatric COVID-19 patients and determine the clinical as well as laboratory parameters predicting co-infection. METHODOLOGY: In this prospective observational study conducted from June to December 2020 in a single tertiary care institution, data pertaining to demographic, illness and treatment-related variables were analyzed among two subsets of pediatric patients of age 1 month-12 years with RT-PCR-confirmed COVID-19 infection-Group A: those with confirmed co-infection and Group B: moderate to severe disease without co-infection. Among Group A, etiology of co-infection was characterized through relevant microbiological examination within 48 h admission. RESULT: Among our study population, 15.03% and 20.6% had co-infections and moderate to severe disease respectively. Among those with confirmed co-infection, 32.5%, 11.6% and 6.97% recorded blood culture, respiratory secretion and CSF growth, respectively, the picture being dominated by Methicillin resistant and sensitive Staphylococcus aureus. Serum serology demonstrated Scrub typhus infection to be most prevalent. Concurrent respiratory viral infections were seen in 11.6%. Children with co-infection had significantly higher morbidity and need for supportive therapy. Predictors of co-infection were localization of infection, Neutrophil count ≥10×109, age-specific lymphopenia, CRP > 100 mg/dl and hyperferritinemia. CONCLUSION: Co-infections are an important factor prognosticating pediatric COVID infection. Their early detection, prompt and appropriate treatment is of paramount importance.


Asunto(s)
COVID-19 , Coinfección , Infecciones Estafilocócicas , Niño , Coinfección/epidemiología , Humanos , Estudios Prospectivos , SARS-CoV-2 , Infecciones Estafilocócicas/diagnóstico , Infecciones Estafilocócicas/epidemiología
16.
J Trop Pediatr ; 67(1)2021 01 29.
Artículo en Inglés | MEDLINE | ID: mdl-33547467

RESUMEN

BACKGROUND: Our goal was to study the demographic, clinical and laboratory profile and outcome of scrub typhus-associated hemophagocytic lymphohistiocytosis (HLH) in the pediatric age group. METHODS: We conducted a prospective observational study in a tertiary care teaching hospital over a period of 1 year. Children in the age group of 1 month to 12 years with IgM ELISA positive for scrub typhus were included in the study. HLH was diagnosed using HLH-2004 criteria. Demographic, clinical and laboratory profile, treatment and outcome of HLH patients were noted and also compared with non-HLH scrub typhus patients. RESULTS: Among 58 children with scrub typhus infection, 18 had HLH. The mean age of patients with HLH was 35.3 ± 44.8 months and 61% were male. Anemia, thrombocytopenia and hyperferritinemia were seen in all the patients. Hypertriglyceridemia, hypofibrinogenemia and coagulopathy were noted in 78%, 56% and 44%, respectively. All the patients were treated with intravenous doxycycline for an average duration of 9.5 days. Intravenous immunoglobulin and methylprednisolone were given in 33% and 22% cases, respectively. Complications like acute respiratory distress syndrome (ARDS) (p = 0.001) and MODS (p = 0.004) were significantly high in the HLH group. Younger age (<3 years), fever > 7 days, presence of convulsion, ARDS and MODS were the clinical predictors of scrub typhus-associated HLH. CONCLUSION: HLH in scrub typhus infected children is being increasingly recognized. Younger age, prolonged fever, presence of convulsion, ARDS and MODS should alert clinicians of the risk of HLH. Treating the primary cause usually cures the disease and immunomodulator therapy need not be routinely administered.


Asunto(s)
Linfohistiocitosis Hemofagocítica , Tifus por Ácaros , Niño , Preescolar , Doxiciclina , Femenino , Fiebre , Humanos , Linfohistiocitosis Hemofagocítica/diagnóstico , Linfohistiocitosis Hemofagocítica/tratamiento farmacológico , Linfohistiocitosis Hemofagocítica/epidemiología , Masculino , Estudios Prospectivos , Tifus por Ácaros/complicaciones , Tifus por Ácaros/diagnóstico , Tifus por Ácaros/tratamiento farmacológico
17.
J Trop Pediatr ; 67(1)2021 01 29.
Artículo en Inglés | MEDLINE | ID: mdl-33347590

RESUMEN

OBJECTIVES: To determine the burden and etiological factors of leave against medical advice (LAMA) in Indian children. METHODOLOGY: In this prospective study, legal guardians of 528 patients who took the decision of LAMA were interviewed (using structured question answers based multi-option) and data were captured over a period of 16 months. The resultant database was analyzed using standard statistical methods. RESULTS: About 6.12% of childhood LAMA cases were dealt out of total pediatric admission including newborns. Neonatal preponderance noted in cases of LAMA from intensive care unit (ICU; 57.14%, p < 0.05). The overall male (n = 293) to female (n = 235) ratio in this study was 1.25:1. Number of LAMA patients was higher from rural area (83.33%), mostly admitted in ICU (93.65%, Pearson's chi-squared test, p < 0.05). Higher proportion (29.47%) of patients with infection availed LAMA from neonatal age group but overall LAMA patients fall under category of respiratory disorders (22.35%). Interest of the domestics issues other than suffering child was considered primary during LAMA for those admitted in ward as compared with ICU patients [odds ratio (OR): 1.73, CI: 1.02-2.94, p < 0.05]. ICU patients were reportedly to be taken to private health care facility (OR: 1.93, CI: 1.06-3.49, p < 0.05). Duration of stay before taking LAMA from ward was <7 days (85.59%, OR: 0.19, CI: 0.11-0.35, p < 0.05). Upper-lower socio-economic class attributed financial constraint as the main reason for LAMA (Pearson's chi-squared test, Chi-square value: 152.23, p < 0.05). CONCLUSIONS: This study tried to elucidate the determinants of childhood LAMA in rural Indian setting.


Asunto(s)
Unidades de Cuidados Intensivos , Niño , Femenino , Humanos , Recién Nacido , Masculino , Estudios Prospectivos
18.
J Org Chem ; 84(16): 10160-10171, 2019 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-31327228

RESUMEN

A simple metal-ligand cooperative approach for the dehydrogenative functionalization of alcohols to various substituted quinolines and quinazolin-4(3H)-ones under relatively mild reaction conditions (≤90 °C) is reported. Simple and easy-to-prepare air-stable Cu(II) complexes featuring redox-active azo-aromatic scaffolds, 2-arylazo-(1,10-phenanthroline) (L1,2), are used as catalyst. A wide variety of substituted quinolines and quinazolin-4(3H)-ones were synthesized in moderate to good isolated yields via dehydrogenative coupling reactions of various inexpensive and easily available starting materials under aerobic conditions. A few control experiments and deuterium labeling studies were carried out to understand the mechanism of the dehydrogenative coupling reactions, which indicate that both copper and the coordinated azo-aromatic ligand participate in a cooperative manner during the catalytic cycle.

19.
J Org Chem ; 84(7): 4072-4085, 2019 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-30855958

RESUMEN

A simple and efficient approach of C-S cross-coupling of a wide variety of (hetero)aryl thiols and (hetero)aryl halides under mild conditions, mostly at room temperature, catalyzed by well-defined singlet diradical Ni(II) catalysts bearing redox noninnocent ligands is reported. Taking advantage of ligand centered redox events, the high-energetic Ni(0)/Ni(II) or Ni(I)/Ni(III) redox steps were avoided in the catalytic cycle. The cooperative participation of both nickel and the coordinated ligands during oxidative addition/reductive elimination steps allowed us to perform the catalytic reactions under mild conditions.

20.
J Org Chem ; 84(5): 2626-2641, 2019 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-30685972

RESUMEN

Simple, straightforward, and atom economic methods for the synthesis of quinolines, 2-aminoquinolines, and quinazolines via biomimetic dehydrogenative condensation/coupling reactions, catalyzed by well-defined inexpensive and easy to prepare singlet diradical Ni(II)-catalysts featuring two antiferromagnetically coupled singlet diradical diamine type ligands are described. Various polysubstituted quinolines, 2-aminoquinolines, and quinazolines were synthesized in moderate to good yields from different low-cost and readily accessible starting materials. Several control experiments were carried out to get insight into the reaction mechanism which shows that the nickel and the coordinated diamine ligands participate in a synergistic way during the dehydrogenation of alcohols.

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