Browsing by Author "Singh, S"

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1-Acetyl-3, 5?diaryl-4, 5?dihydro (1H) pyrazoles: Exhibiting Anticancer Activity through Intracellular ROS Scavenging and the Mitochondria-Dependent Death Pathway
(Wiley, 2014) Alex, JM; Singh, S; Kumar, Raj
A series of 17 analogs of 1?acetyl?4,5?dihydro(1H)pyrazoles (JP?1 to JP?17) bearing two aromatic rings at positions 3 and 5, either of which ought to be heterocyclic, were synthesized and evaluated for their anti?proliferative potential against breast cancer (MCF?7 and T?47D) and lung cancer (H?460 and A?549) cell lines for the first time.JP-1–7, -10, -11, -14, and ?15 were observed to exhibit significant anti?proliferative activity against MCF?7 cells. Some notions about structure - activity relationships are reported. The investigated compounds were found to lower the intracellular reactive oxygen species in the H2DCFDA assay and also caused mitochondria?dependent cell death in the MCF?7 cell line, indicating a plausible mechanism of their anticancer effect.
Employability and Earning Differentials Among Technically and Vocationally Trained Youth in India
(Springer, 2020) Singh, S; Parida, J.K; Awasthi, I.C.
Based on both NSS (1993�94, 1999�2000, 2004�05, and 2011�12 rounds) and PLFS (2017�18) data, this paper examines the employability and earning/wage differentials among vocationally and technically trained youth and explored its determinants in India. It is found that although the number of vocationally and technically trained youth increased during the last decade, their work force participation had declined substantially. We have also noted an upsurge in the open unemployment among these trained youth. The job market distress is being reflected by the large share of employment of these trained youth in agriculture and allied sectors or in the low paid and informal service sectors, and lack of employment opportunities in industries. Moreover, the prevalence of both stick floor (in case of female) and glass ceiling (in case of Backward Castes) effects in the vocational and technical labour market is the main reason for the existing wage differential by gender and caste groups in India. Based on these findings, it is suggested that reducing the labour market demand-supply gap through required job opportunities in industry is necessary. This would not only improve the employability of vocationally and technically trained youth, but also help reducing their existing wage differentials. � 2020, Indian Society of Labour Economics.
Exploration of Pd-catalysed four-component tandem reaction for one-pot assembly of pyrazolo[1,5-c]quinazolines as potential EGFR inhibitors
(Academic Press Inc., 2019) Ansari, A.J; Joshi, G; Yadav, U.P; Maurya, A.K; Agnihotri, V.K; Kalra, S; Kumar, R; Singh, S; Sawant, D.M.
A series of pyrazolo[1,5-c]quinazolines as EGFR inhibitors was designed and synthesized by highly efficient and novel multicomponent route involving Pd-catalyzed tandem one-pot four-component reaction. The reaction proceeds with good functional group tolerance under a simple condition with excellent regioselectivity and high efficiency. Target compounds were screened against cancer cell lines MDA-MB-231, A549 and H1299. Of these, 9b and 10b exhibited superior anticancer activity (IC50 < 2.5 ?M) to erlotinib and gefitinib. Synthetics were able to inhibit EGFR mediated kinase activity, induced ROS in cancer cells promoting mitochondrial mediated apoptosis via halting cell cycle progression at G1 phase.
Pd-Catalyzed Four-Component Sequential Reaction Delivers a Modular Fluorophore Platform for Cell Imaging
(American Chemical Society, 2019) Ansari, A.J; Joshi, G; Sharma, P; Maurya, A.K; Metre, R.K; Agnihotri, V.K; Chandaluri, C.G; Kumar, Raj; Singh, S; Sawant, D.M.
A Pd-catalyzed cascade reaction of four versatile privileged synthons is described. The sequential reaction involves the formation of five new chemical bonds by concatenating three distinct chemical steps. One of the derivatives exhibited absorption in the visible region, fluorescence with a high quantum yield, and excellent photostability. Its application is explored in live cell imaging, which exhibited cytoplasmic and mitochondrial specific staining with no toxicity. © 2019 American Chemical Society.
Stability and tunable electronic structure of planar phosphorus nanotubes
(American Institute of Physics, 2019) Singh, S; Kaur, S; Gupta, S.K; Kumar, Ashok; Srivastava, S.
The stability and electronic properties of planar phosphorous nanotubes with different chirality are investigated within the formulation of density functional theory. Armchair phosphorous nanotube (APNT) is found to be energetically most favorable with very small formation energy (0.08 eV). APNT also possess highest tensile strength (∼2 GPa), among the considered nanotubes. Armchair and helical PNTs are semiconducting while zigzag PNT is metallic in nature. We found that the application of strain and external electric field greatly modifies the electronic band structure of given PNTs. We believe that planar APNT can be realized and its tunable electronic properties may be useful for nanoelectronics. © 2019 Author(s).
Synthetic versus Enzymatic Pictet-Spengler Reaction: An Overview.
(Bentham, 2018) Sharma, S; Kalra, S; Joshi, G; Singh, S; Kumar, R.
Pictet-Spengler reactions is an irreplaceable part of cyclization reaction leading to the formation of indispensable heterocyclic moieties including imidazole, benzoxazole, pyrrole, indole and others having immense biological and chemical significance. Researchers have explored this reaction using different types of catalysts and reactions conditions (including solvents, acids, etc.) to ensure the better selectivity, less reaction time and high product yields. A total of five Pictet-Spenglerases have been discovered from various sources including plants, animals, fungi, and microbes, and are responsible for the synthesis of various important alkaloids of biological medicinal importance. Objective: The present review is a strenuous effort to assemble information mainly focusing on synthetic as well as biological Pictet-Spengler reactions catalysed by enzymes called Pictet-Spenglerase. Conclusion: In the present review, the recent advances in the PS-mediated synthesis of diverse heterocycles such as tetrahydroisoquinoline, tetrahydro-β-carbolines, tetrahydroimidazopyridines and other fused heterocycles via chemical as well as enzymatic pathways have been covered. The compounds find their scope as medicinal agents for the treatment of cancer, tuberculosis, bacterial infection, leishmanial, etc. The compilation is expected to provide a mechanistic insight to chemists to enhance the reaction condition, yields and another parameter to ensure the safe and inexpensive reaction conditions considering the “Green-Concept” of chemistry.