Browsing by Author "Kaur, Pavneet"

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    Chitosan-supported copper as an efficient and recyclable heterogeneous catalyst for A3/decarboxylative A3-coupling reaction
    (Elsevier Ltd, 2018) Kaur, Pavneet; Kumar, Bhupinder; Kumar, Vinod; Kumar, Rakesh
    Chitosan-supported copper (chit@copper) based heterogeneous catalysts have been explored for A3-coupling and decarboxylative A3-coupling. The developed protocol employs low catalyst loading, solventless condition and easy work-up for the synthesis of diversely substituted propargylamines. More importantly, the catalyst could be recovered and reused without any significant loss in the activity. This offer huge advantages as recyclability issues are rarely addressed in decarboxylative A3-coupling. Leaching studies were carried out using AAS and ICPMS analysis. It is envisaged that chit@copper catalysts can have potential applications in terms of efficiency and recyclability in the emerging area of decarboxylative C?H bond activation/functionalization strategies. ? 2018 Elsevier Ltd
  • No Thumbnail Available
    Item
    Chitosan-supported FeCl3 catalyzed multicomponent synthesis of tetrahydroisoquinoline-indole hybrids with promising activity against chloroquine resistant Plasmodium falciparum
    (Elsevier B.V., 2022-10-26T00:00:00) Kaur, Pavneet; Sharma, Priyanka; Kumar, Vinod; Sahal, Dinkar; Kumar, Rakesh
    An operationally simple three-component coupling of tetrahydroisoquinoline (THIQ), aldehydes and indoles or indole-3-carboxylic acids has been achieved using chitosan-ionic liquid supported FeCl3 (chit-IL@FeCl3) as a recyclable heterogeneous catalyst. The developed waste-free approach provided rapid access to biologically important THIQ-indole hybrids without the use of any additive or ligand. The synthesized THIQ-indole hybrids were evaluated as antiplasmodial agents against chloroquine-sensitive (Pf3D7) and chloroquine-resistant (PfINDO) strains of Plasmodium falciparum. Compounds 4b (most potent against Pf3D7) and 4g (most potent against PfINDO) showed IC50 values of 1.32 and 0.26 �g/mL respectively. Also, 4g showed strong cytocidal action against both rings and trophozoite stages. Furthermore, cytotoxic study against human liver HUH 7 cells revealed that the most potent compound 4g with an excellent resistance index of 0.07 is also relatively non-toxic. The results of this study suggest that THIQ-indole hybrids hold an enormous potential for developing new antimalarial agents with novel mechanism of action. � 2022 Elsevier B.V.
  • No Thumbnail Available
    Item
    Efficient synthesis and mechanistic insights for the formation of imidazo[1,2-a]pyridines via multicomponent decarboxylative coupling using chitosan-supported copper catalysts
    (Elsevier B.V., 2023-10-03T00:00:00) Kaur, Pavneet; Gurjar, Kamlesh K.; Arora, Tania; Bharti, Divya; Kaur, Manpreet; Kumar, Vinod; Parkash, Jyoti; Kumar, Rakesh
    An efficient multicomponent decarboxylative coupling of 2-aminopyridines, aldehydes and alkynoic acids for the synthesis of imidazo[1,2-a]pyridines was developed using recyclable chitosan-supported copper (chit@CuSO4) as a heterogeneous catalyst. Computational and experimental evidence revealed that in situ generated propargylamine undergoes cyclization to the desired imidazopyridine via prototropic isomerization involving allene type intermediates. Control experiments on isolated propargylamine demonstrated that cyclization could proceed without any metal catalyst. In literature, the cyclization step is assumed to be facilitated by metal catalyst and experimental proof for the involvement of actual intermediates is not available. The synthesized imidazopyridines were further evaluated for antiproliferative activity against human neuroblastoma cells (SHSY-5Y) using MTT assay. � 2023 Elsevier B.V.
  • No Thumbnail Available
    Item
    Role of Contract Farming in Crop Diversification and Employment Generation: Empirical Evidence from Indian Punjab
    (SAGE Publications Ltd, 2021-11-01T00:00:00) Kaur, Pavneet; Singla, Naresh; Singh, Sukhpal
    Linking small farmers with modern agri-business firms through contract farming is viewed as one of the several ways to achieve crop diversification and enhance farmers� income, besides bringing spill-over effects of such interventions for other local stakeholders like farm workers. This article examines the role of contract farming in crop diversification and employment generation in the context of Indian Punjab. Based on a sample of 50 contract farmers and 50 non-contract farmers for three firms each, the study shows that contract farming brings crop diversification and generates farm labour employment, particularly for women, due to the high value and labour-intensive nature of crops being grown under such arrangements. But, there exists a gender gap in wages and gendering of tasks, which demand policy and corporate attention besides regulatory oversight to achieve more equitable and pro-poor impact of contract farming. � 2021 Association of Asia Scholars.
  • Thumbnail Image
    Item
    Role of land reforms in eradicating land inequalities in rural india
    (Society of Economics and Development, 2016) Singla, Naresh; Kaur, Pavneet; Ahmed, Mumtaz