Browsing by Author "Promod Kumar"

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A practical protocol for the synthesis of bibenzyls: Via C(sp3)-H activation of methyl arenes under metal-free conditions
(Royal Society of Chemistry, 2017) Promod Kumar; Tirumaleswararao Guntreddi; Rahul Singh; Krishna Nand Singh
A variety of bibenzyl derivatives have been synthesized with excellent atom economy via C(sp3)-H-C(sp3)-H coupling of readily available methyl arenes using K2S2O8 under metal-free and environmentally benign conditions. © 2016 the Partner Organisations.
Elemental sulfur mediated synthesis of benzoxazoles, benzothiazoles and quinoxalines: Via decarboxylative coupling of 2-hydroxy/mercapto/amino-anilines with cinnamic acids
(Royal Society of Chemistry, 2016) Tirumaleswararao Guntreddi; Rajeshwer Vanjari; Saurabh Kumar; Rahul Singh; Neetu Singh; Promod Kumar; Krishna Nand Singh
An easy and practical method has been developed for the synthesis of 2-benzylbenzoxazoles and 2-benzylbenzothiazoles using sulfur mediated decarboxylative coupling of cinnamic acids with 2-hydroxyanilines and 2-mercaptoanilines respectively under metal- and solvent-free conditions. However, the reaction of 2-aminoanilines with cinnamic acids leads to the formation of 2-arylquinoxalines under the same set of reaction conditions. The transformation is versatile and compatible with a number of functional groups. © 2016 The Royal Society of Chemistry.
Immunoblot analysis of the humoral immune response to Leishmania donovani polypeptides in cases of human visceral leishmaniasis: Its usefulness in prognosis
(2002) Promod Kumar; Kalpana Pai; Kiran Tripathi; H.P. Pandey; Shyam Sundar
Sera from Indian patients with parasitologically confirmed visceral leishmaniasis were studied by immunoblot analysis in order to identify a specific pattern for Leishmania infection. A soluble extract of Leishmania donovani was used as antigen. At diagnosis the sera from patients with visceral leishmaniasis specifically recognized fractions represented by bands of 201 kDa (50% of serum samples), 193 kDa (60%), 147 kDa (50%), 120 kDa (60%), 100 kDa (50%), 80 kDa (80%), 70 kDa (70%), 65 kDa (100%), 50 kDa (50%), 36 kDa (50%), 20 kDa (70%), and 18 kDa (50%). The 65-kDa band, common to all patients infected with Leishmania parasites, was found at the time of diagnosis. However, the immunoblot pattern changed after patients were treated and cured with sodium antimony gluconate (SAG; n = 10) or miltefosine (n = 10), as was evident from blots of sera obtained pretreatment and at 1, 3, and 6 months posttreatment. At 6 months posttreatment, immunoblots of sera from patients on the SAG regimen showed the disappearance of all bands except the 70-kDa band. Similarly, sera from those on the miltefosine regimen showed the disappearance of all bands except the 65- and 70-kDa bands. This study shows that Western blot analysis is a sensitive test for detection of anti-Leishmania antibodies. Moreover, the persistence of reactivity with the 65- and 70-kDa bands in the sera of all groups shows its promise as a diagnostic and prognostic tool.
NADH-oxidase, NADPH-oxidase and myeloperoxidase activity of visceral leishmaniasis patients
(Lippincott Williams and Wilkins, 2002) Promod Kumar; Kalpana Pai; Haushila P. Pandey; Shyam Sundar
It is believed that the enhanced capability of activated macrophages to resist infection is related to the remarkable increase in the production of oxygen metabolites in response to phagocytosis. Both the production of H2O2 and the oxidation of NAD(P)H are directly dependent upon NAD(P)H-oxidase. It has been established that the respiratory burst is due to activation of NAD(P)H-oxidase localised in the plasmalemma. Myeloperoxidase is believed to be involved in augmenting the cytotoxic activity of H2O2. Low NADH-oxidase, NADPH-oxidase and myeloperoxidase activity were observed in monocytes of patients with active visceral leishmaniasis as compared with healthy controls. These results suggest that low NADH-oxidase, NADPH-oxidase and myeloperoxidase activities may account for persistence of Leishmania parasites in visceral leishmaniasis.
Nickel Catalyzed Ipso-hydroxylation and Subsequent Cross Dehydrogenative Coupling of Arylboronic Acids with Tertiary Amines: A Facile Access to α-phenolated Tertiary Amines
(Wiley-VCH Verlag, 2018) Promod Kumar; Anup Kumar Sharma; Rahul Singh; Tirumaleswararao Guntreddi; Krishna Nand Singh
A straightforward and new approach has been developed for the α-functionalization of tertiary amines via sequential oxidative hydoxylation and cross-dehydrogenative coupling (CDC) of arylboronic acids with tertiary amines to afford α-phenolated tertiary amines. The results demonstrate an easy arylation of C(sp3)−H bond in the presence of an inexpensive and readily available nickel metal salt. (Figure presented.). © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Soil sensors: detailed insight into research updates, significance, and future prospects
(Elsevier, 2017) Alka Dwevedi; Promod Kumar; Pravita Kumar; Yogendra Kumar; Yogesh K. Sharma; Arvind M. Kayastha
Soil is an important natural resource that requires crucial attention due to its significant role in crop yield. There is substantial ongoing research on soil health, particularly its water retention capability, moisture content, salinity, temperature, pH, concentration of dissolved gases, etc. Technologies have evolved that can remotely monitor soil and track its various parameters without being physically present in the field, using various probes (coaxial impedance dielectric reflectometry sensors, frequency domain reflectometry sensors, time domain reflectometry sensors, gypsum blocks, neutron probes, etc.). These probes are extremely accurate and provide information about the soil’s surface as well as its inner layers with respect to moisture content, salinity, and temperature. Thus, the probes are helpful for farmers in increasing crop yield by adopting an optimum level of irrigation and suitable fertilizers. The usage of soil probes would be helpful for the economical use of water, as well as of chemical fertilizers to subsequently reduce their toxicity to growing crops. Research scientists studying earth and its environmental processes are always keen to know the processes going on inside the soil. These soil sensors buried in different soil horizons are able to provide complete information to scientists’ lab desktops, even without going to the topographical location. These soil probes are kept intact within the soil with no gaps between the soil and probes to obtain an accurate picture of the soil environment. However, the most tedious aspect is to select the right sensor based on the type of soil and the precision required. This chapter details recent developments on soil sensors, data analysis obtained, and their applications in fields, as well as their shortcomings, if any. © 2017 Elsevier Inc. All rights reserved.
Study on pinocytosis by monocytes from visceral leishmaniasis patients
(2002) Promod Kumar; Kalpana Pai; Haushila P. Pandey; Shyam Sundar
In the present study, we report that monocytes obtained front active visceral leishmaniasis (VL) patients show low rate of pinocytosis compared to that of healthy controls. Several studies have suggested that any change in pinocytic activity reflects changes in the functional state of the cell. In the present study we have evaluated pinocytosis by monocytes obtained from patients with VL. A reduced pinocytic activity by monocytes from active VL patients was observed in comparison to healthy controls. Our study suggests that reduced pinocytic rate by monocytes in active VL infection reflects down-regulation of macrophage activation or functional state.
Transition-Metal-Free Cross-Dehydrogenative Coupling of Ethyl Arylacetates with Benzoic/Cinnamic Acids: A Practical Synthesis of α-Acyloxy Esters
(Wiley-VCH Verlag, 2018) Anup Kumar Sharma; Promod Kumar; Ramesh Kumar Vishwakarma; Krishna Nand Singh
An efficient cross-dehydrogenative coupling of benzylic C(sp3)−H of ethyl arylacetates with benzoic/cinnamic acids has been developed to afford α-acyloxy esters in reasonably high yields under environmentally benign conditions. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Transition-Metal-Free Regiospecific Aroylation of Nitroarenes Using Ethyl Arylacetates at Room Temperature
(American Chemical Society, 2018) Promod Kumar; Anup Kumar Sharma; Tirumaleswararao Guntreddi; Rahul Singh; Krishna Nand Singh
A novel regiospecific C(sp3)-C(sp2) coupling between ethyl arylacetates and nitroarenes has been developed to deliver biaryl ketones in excellent yields. The protocol is metal-free, mild, and compatible with a number of functional groups on both of the reacting partners. © 2018 American Chemical Society.
Visible-Light-Enabled Synthesis of Pyridyl Benzamides via Oxidative Decarbethoxylation using Copper(I) Iodide/Air at Room Temperature
(Wiley-VCH Verlag, 2019) Anup Kumar Sharma; Promod Kumar; Ramesh Kumar Vishwakarma; Krishna Nand Singh
An efficient synthesis of N-(pyridin-2-yl)benzamides has been developed by the reaction of 2-aminopyridines and ethyl arylacetates via oxidative decarbethoxylation using visible light/CuI/O2 in acetonitrile at room temperature. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim