Browse
Recent Submissions
Item Recent advances in 4CzIPN-mediated functionalizations with acyl precursors: single and dual photocatalytic systems(2024) Kishor Padala4CzIPN (1,2,3,5-tetrakis(carbazole-9-yl)-4,6-dicyanobenzene) has emerged as a key metal-free photocatalyst for sustainable organic synthesis. Due to its unique design enabling high photoluminescence quantum yield, thermally activated delayed fluorescence (TADF) and long excited state lifetime, 4CzIPN facilitates diverse reactions, such as C–C and C–X bond formation reactions, under mild reaction conditions. This review highlights its application in decarboxylation, acylation and cyclisation reactions involving α-keto acids, carboxylic acids and aldehydes in a single catalytic system, as well as the combination of a dual catalytic system with transition metals to enhance selectivity and scope. 4CzIPN contributes to the advancement of sustainable chemistry by enabling green, efficient and scalable reactions and this review covers studies published between 2020 and 2024.Item The isolation-biological activities (2014–2022), bio, semi, total synthesis (1978–2022) and SAR studies of a potential naturally engineered scaffold aristolactam(2023) Kishor PadalaAristolactams are a small group of aporphinoid alkaloids containing the phenanthrene chromophore that were first isolated from Aristolochia argentina (Aristolochiaceae), which is the richest source of this family of alkaloids. Plants containing aristolactam alkaloids have also been used in traditional medicine to treat various diseases. Thus, in this review, we compile and summarise the recent structures, isolation and biological activities of new and known aristolactam alkaloids from 2014 to 2022, and the total synthetic approaches to the natural products bearing an aristolactam motif from 1978 to 2022. Focus has been given to ingenious strategies to functionalize the aristolactam moiety at multiple positions. In addition, the SAR studies of a potential naturally engineered aristolactam scaffold are discussed.Item The recent advances in cobalt-catalyzed C(sp3)–H functionalization reactions(2022) Kishor PadalaOver the past decades, reactions involving C–H functionalization have become a hot theme in organic transformations because they have a lot of potential for the streamlined synthesis of complex molecules. C(sp3)–H bonds are present in most organic species. Since organic molecules have massive significance in various aspects of life, the exploitation and functionalization of C(sp3)–H bonds hold enormous importance. In recent years, the first-row transition metal-catalyzed direct and selective functionalization of C–H bonds has emerged as a simple and environmentally friendly synthetic method due to its low cost, unique reactivity profiles and easy availability. Therefore, research advancements are being made to conceive catalytic systems that foster direct C(sp3)–H functionalization under benign reaction conditions. Cobalt-based catalysts offer mild and convenient reaction conditions at a reasonable expense compared to conventional 2nd and 3rd-row transition metal catalysts. Consequently, the probing of Co-based catalysts for C(sp3)–H functionalization is one of the hot topics from the outlook of an organic chemist. This review primarily focuses on the literature from 2018 to 2022 and sheds light on the substrate scope, selectivity, benefits and limitations of cobalt catalysts for organic transformations.Item TMSOTf-Promoted Synthesis of Quinazolin-4(3H)-one Utilizing DMSO as a Carbon Source(2023)An efficient TMSOTf-promoted multicomponent reaction has been developed for the one-pot synthesis of quinazolin-4 (3H)-ones. Using the TMSOTf as a Lewis acid promoter and DMSO as a carbon source, the reaction of isatoic anhydride, primary amines yielded a variety of quinazolines-4 (3H)-ones. Additionally, TMSOTf promoted the reaction of 2-amino-N-substituted benzamide with DMSO yielding the same scaffolds in high yields. However, the use of DMSO-d6 as a solvent in the reaction enabled the incorporation of the −CD moiety in quinazolines-4 (3H)-one skeleton. This proves that DMSO plays a twin role as a C1 source and solvent. Various functional groups containing a wide range of quinazolin-4 (3H)-ones and other heterocycles were developed employing this methodology. Also, the synthetic methodology has been extended for the synthesis of 3-(2-carboxyphenyl)-4-(3H)-quinazolinone, as an anti-endotoxic drug.Item Sustainable synthesis of nitrogen rich pyridazine-triazole scaffolds as efficient Tyrosine kinase inhibitors via Click reaction(2025) Kishor PadalaThe Cu-catalyzed click reaction was employed to furnish 1H-1,2,3-triazoles from substituted phenylacetylenes and 6-azido-3-nitroimidazo[1,2-b]pyridazine through which the resulting 3-nitroimidazo[1,2-b]pyridazine-triazoles (4a-4k) achieved in yields between 82‐98 %. In silico approach identified compounds as the most promising candidates to assess their tyrosine kinase inhibition capabilities. The target compounds with bromo, hydroxy, acetyl and methyl groups at para positions were subjected for In vitro assessments according to their Tyrosine Kinase (TK) enzyme binding affinity. All synthesized compounds fulfilled the criteria for drug likeness according to their ADMET profile assessment. The investigated compounds demonstrated medium-level to good activity against multiple TK enzymes; specifically, compounds with acetyl substitution demonstrated lower IC50 values, whereas hydroxy-substituted compounds presented higher IC50 values across all tested TK enzymes. DFT investigations demonstrated that acetyl substituted molecules react strongly with lower stability and a significant dipole moment (10.16 Debye) followed by methyl substituted.Item A Comprehensive Exploration of the Synergistic Relationship between DMSO and Peroxide in Organic Synthesis(2024) Kishor PadalaIn the realm of organic synthesis, reagents can serve not only as solvents but also as synthons. Dimethyl sulfoxide (DMSO) is recognized for its efficiency in this dual capacity, enabling diverse chemical transformations. DMSO can generate various synthons, including methyl, methylene, methine, oxygen, and methyl sulfoxide, broadening the accessible compound repertoire. Activation of DMSO as a reagent relies heavily on synergies with secondary agents like peroxide, persulfate, or iodine. Recent years have witnessed a surge in innovative synthetic techniques harnessing the synergistic interplay of DMSO and peroxide, leading to environmentally friendly and cost-effective reactions with mild conditions. This review highlights the synergistic effects of DMSO and peroxides (up to 2023), detailing their activation mechanisms and the generation of various synthons, along with numerous reported derivatives. Although this topic has received considerable attention in recent years, there are numerous discrepancies and a plethora of possibilities yet to be explored. We anticipate that this review will significantly support researchers in advancing their innovations to a greater extent in the future.Item An exfoliated redox active imide covalent organic framework for metal free hydrogen gas sensing†(2023) Kalidindi, Suresh BabuA two dimensional (2D) redox active donor–acceptor COF made of triphenylamine (TPA) and naphthalenediimide (NDI) acted as an efficient hydrogen chemisresistor and performed better than traditional metal oxides. Calculations have shown that the charge transfer interaction between H2 and an NDI linker through a carbonyl functionality enables a change in the resistance of the material upon exposure to H2 gas.Item Acidic graphene organocatalyst for the superior transformation of wastes into high-added-value chemicals(2022) Kalidindi, Suresh BabuOur dependence on finite fossil fuels and the insecure energy supply chains have stimulated intensive research for sustainable technologies. Upcycling glycerol, produced from biomass fermentation and as a biodiesel formation byproduct, can substantially contribute in circular carbon economy. Here, we report glycerol’s solvent-free and room-temperature conversion to high added-value chemicals via a reusable graphene catalyst (G-ASA), functiona lized with a natural amino acid (taurine). Theoretical studies unveil that the superior performance of the catalyst (surpassing even homogeneous, indus trial catalysts) is associated with the dual role of the covalently linked taurine, boosting the catalyst’s acidity and affinity for the reactants. Unlike previous catalysts, G-ASA exhibits excellent activity (7508 mmolg−1 h−1)andselectivity (99.9%) for glycerol conversion to solketal, an additive for improving fuels’ quality and aprecursorofcommodityandfinechemicals.Notably,thecatalyst is also particularly active in converting oils to biodiesel, demonstrating its general applicability.Item H2O2‑Mediated Synthesis of a Quinazolin-4(3H)‑one Scaffold: A Sustainable Approach(American Chemical Society, 2023) Kishor PadalaA quinazolin-4(3H)-one ring system is a privileged heterocyclic moiety with distinctive biological properties. From this perspective, the development of an efficient strategy for the synthesis of quinazolin-4(3H)-one has always been in demand for the synthetic chemistry community. In this report, we envisaged an efficient protocol for the synthesis of quinazolin-4(3H)-one using substituted 2-amino benzamide with dimethyl sulfoxide (DMSO) as a carbon source and H2O2 as an effective oxidant. Mechanistically, the reaction proceeds through the radical approach with DMSO as one carbon source. To further substantiate the synthetic claim, the synthetic protocol has been extended to the synthesis of the anti-endotoxic active compound 3-(2- carboxyphenyl)-4-(3H)-quinazolinone.