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Item Iodine(III)-induced cascade annulation of β-cyanoporphyrins for the efficient synthesis of n-aryliminonaphtho-fused and n-aryl-carboxamide porphyrins(Wiley, 2025-12) Grover, Nitika; Kumar, DalipMeso-β fused porphyrins with tunable optoelectronic properties are attractive candidates for applications in light-harvesting, sensing, and catalysis, yet their synthesis often requires harsh conditions or tedious synthetic routes. Herein, a mild, operationally simple, and Cu(OTf)2-catalyzed protocol is reported to access meso-N-aryliminonaphtho-fused and N-arylcarboxamide porphyrins from readily available β-cyanoporphyrins and diaryliodonium salts. Reaction selectivity is controlled by the water content present in the reaction mixture, affording either fused imines or carboxamides in high yields. The protocol tolerates different symmetrical diaryliodonium salts and enables the preparation of free-base, Zn (II), and Cu (II) porphyrin derivatives, all fully characterized by NMR, UV–visible spectroscopy, high resolution mass spectrometry, electrochemistry, and single crystal X-ray diffraction. The π-extended systems exhibit distinct bathochromic shifts (≈42 nm in Soret and ≈80–90 nm in Q-bands) and narrowed highest molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gaps up to 1.54 eV. Electrochemical studies reveal that fused porphyrins exhibited anodically shifted reduction potentials, while Density functional theory calculations attribute the gap reduction to LUMO stabilization and HOMO destabilization induced by fusion. Overall, this strategy provides rapid access to structurally diverse π-extended porphyrins with tailored photophysical and redox properties.Item L-Proline catalysed synthesis and in silico studies of novel α-cyano bis(indolyl)chalcones as potential anti-cancer agents(RSC, 2025-02) Kumar, DalipA diverse range of α-cyano bis(indolyl)chalcones (21a–r) were synthesized in high yields (90–95%) through the L-proline catalysed reaction of appropriate aldehydes and 3-cyanoacetylindoles. Formation of α-cyano bis(indolyl)chalcones involves readily available starting materials, catalytic L-proline, environmentally benign and metal-free conditions. The prepared eighteen α-cyano bis(indolyl)chalcones 21a–r were screened against prostate, breast, epithelial cancer cells and found to be non-cytotoxic to normal HEK293 cells. The α-cyano bis(indolyl)chalcones 21a (3.9 μM), 21c (7.5 μM), 21i (2.2 μM) and 21o (5.9 μM) displayed good cytotoxicity against C4-2 cells, whereas, derivatives 21c (1.23 μM), 21h (5.23 μM), and 21l (2.5 μM) showed selective cytotoxicity against 22Rv1 cells. With broad spectrum of activity (0.98–5.6 μM), the compound 21j was found to increase the endogenous level of ROS, upregulate the level of p-53 and c-jun besides mitochondrial dysfunction, cause apoptosis.Item A facile and efficient synthesis of bodipy-based fluorescent probes for selective detection of hydrazine(Wiley, 2024-11) Sarkar, Madhushree; Kumar, DalipA facile and ratiometric BODIPY-based fluorescent probe 4 was developed for the selective detection of hydrazine in solution phase. The BODIPY-based fluorophores 3 and 4 were easily prepared in high yields from the L-proline catalyzed reaction between α/β-formyl BODIPY 1 a/1 b and 3-cyanoacetylindole 2. Use of easily accessible substrates, benign solvent, catalytic amount of L-proline and high product yields are the advantageous features of the developed protocol. Prepared BODIPYs 3 (536 nm) and 4 (567 nm) showed bathochromic shifts (36–67 nm) in UV-Visible absorption maxima when compared to parent BODIPY (500 nm) in dichloromethane (DCM). The stable and economical BODIPY-based probe 4 exhibited rapid response and remarkable selectivity towards hydrazine when compared to other commonly occurring analytes. At low concentration, the BODIPY probe 4 (10 μΜ) is non-fluorescent, however, a significant enhancement in fluorescent (turn-on) was observed with the increasing concentration of hydrazine (0–100 μΜ). This change in fluorescent behaviour may be ascribed to intramolecular charge transfer (ICT) effect as supported by density functional theory (DFT) calculations. With a 4.3 μM detection limit, the BODIPY probe 4 was also found to be useful in detecting hydrazine in real environmental samples.Item Synthesis of N-heterocycle-ligated porphyrins using iodobenzene diacetate enabled regioselective cross-dehydrogenation of porphyrins and NH-heteroaromatics(ACS, 2025-03) Kumar, DalipPreparation of diverse meso-functionalized porphyrins involves iodine(III)- and copper triflate-promoted dehydrogenative coupling of meso-free porphyrins and appropriate NH-free heterocycles. Reaction conditions involving the stable and recyclable iodobenzene diacetate reagent are compatible with a range of NH-free heterocycles (acridone, phenoxazine and phenothiazine, carbazole, β-carbolin triazoles, imidazole, pyrazole, indazole, and tetrazole) and porphyrins to access diversely functionalized A3B, A2BC, and A2B2 porphyrins in moderate to good yields. The prepared heterocycle-appended porphyrins exhibit modestly red-shifted Soret and Q bands in the absorption spectra.Item Iodine(iii)-promoted regioselective and efficient synthesis of β-triazolyl BODIPYs for the selective recognition of nickel ions and bovine serum albumin(RSC, 2022) Sarkar, Madhushree; Kumar, DalipVarious β-triazolyl tethered BODIPYs were efficiently prepared in a sequential one-pot protocol involving the initial reaction of BODIPY with iodobenzene diacetate (IBD) and sodium azide to in situ generate BODIPY azides followed by a copper-catalyzed azide–alkyne cycloaddition reaction. Under the optimized reaction conditions, various β-triazolyl BODIPYs 5a–i were successfully prepared in good yields and adequately characterized by using UV, NMR, mass spectral data and XRD analyses. The UV-Visible spectra of the prepared β-triazolyl BODIPYs 5a–i showed intense absorption bands (514–545 nm) with a 13–44 nm red shift when compared with those of the parent BODIPY. The selective recognition of compound 5d towards Ni2+ ions (detection limit 0.26 nM) led to significant quenching in the fluorescence intensity over other selected bivalent metal ions. The complex formed between 5d and Ni2+ in a stoichiometry of 2 : 1 was found to have a binding constant of 7.5 × 105 M−1. The fluorescence of compound 5i gets enhanced gradually upon interaction with bovine serum albumin due to its selective and high binding affinity (1.25 × 105 M−1) with protein and a concomitant decrease in the total non-radiative decay rate.Item Asymmetric Synthesis of Bridged N-Heterocycles with Tertiary Carbon Center through Barbas Dienamine-Catalysis: Scope and Applications(ACS, 2021-11) Kumar, Indresh; Kumar, DalipA direct aza-Diels–Alder reaction between 2-aryl-3H-indolin-3-ones and cyclic-enones has been developed to access chiral indolin-3-one fused polycyclic bridged compounds. This method proceeds via proline-catalyzed Barbas-dienamine intermediate formation from various cyclic-enones such as 2-cyclopenten-1-one, 2-cyclohexene-1-one, and 2-cycloheptene-1-one, followed by a reaction with 2-aryl-3H-indol-3-ones. Several indolin-3-ones fusing [2.2.2], [2.2.1], and [3.2.1] skeletons decorated with a tertiary carbon chiral center have been prepared. Computational studies (DFT) supported the observed stereoselectivity in the method. The synthesized compounds have shown exciting photophysical activities and selective sensing of Pd2+ and Fe3+ ions through the fluorescence quenching “switch-off” mode.Item Direct Amine-Catalyzed Enantioselective Synthesis of Pentacyclic Dibenzo[b,f][1,4]oxazepine/Thiazepine-Fused Isoquinuclidines along with DFT Calculations(ACS, 2020-10) Kumar, Dalip; Kumar, IndreshA direct protocol for the asymmetric synthesis of dibenzoxazepine/thiazepine-fused [2.2.2] isoquinuclidines is developed. The reaction proceeds through a proline-catalyzed direct Mannich reaction followed by an intramolecular aza-Michael cascade sequence between 2-cyclohexene-1-one and various tricyclic imines, like dibenzoxazepines/thiazepines, as an overall [4 + 2] aza-Diels–Alder reaction. A series of pentacyclic isoquinuclidines have been prepared, with complete endo-selectivity, in good to high yields and excellent enantioselectivity (>99:1). Density functional theory (DFT) calculations further support the observed high stereochemical outcome of the reaction.Item Substrate or Solvent-Controlled PdII-Catalyzed Regioselective Arylation of Quinolin-4(1H)-ones Using Diaryliodonium Salts: Facile Access to Benzoxocine and Aaptamine Analogues(Wiley, 2020-03) Kumar, DalipRegioselective C3, C5, and C8 arylation of quinolin-4(1H)-ones have been accomplished either by substrate-control or by tuning the reaction solvent. A variety of aryl(mesityl)iodonium triflates could smoothly deliver arylated products in good to excellent yields. Additionally, it offers great flexibility by arylating medicinally potent quinolone related heterocycles such as acridin-9(10H)-one, and phenanthridin-6(5H)-one under standard reaction conditions. This strategy was further extended with diphenyleneiodonium triflate to access oxacine fused quinolines. The post-modifications of synthesized products enhance the further utility of this protocol in organic synthesis. To the best of our knowledge, this is the first report on C5 arylation of quinolin-4(1H)-ones using iodine(III) reagents.Item Chemoselective Cu-catalyzed synthesis of diverse N-arylindole carboxamides, β-oxo amides and N-arylindole-3-carbonitriles using diaryliodonium salts(RSC, 2024-09) Kumar, DalipChemoselective copper-catalyzed synthesis of diverse N-arylindole-3-carboxamides, β-oxo amides and N-arylindole-3-carbonitriles from readily accessible indole-3-carbonitriles, α-cyano ketones and diaryliodonium salts has been developed. Diverse N-arylindole-3-carboxamides and β-oxo amides were successfully achieved in high yields under copper-catalyzed neutral reaction conditions, and the addition of an organic base (DIPEA) resulted in a completely different selectivity pattern to produce N-arylindole-3-carbonitriles. Moreover, the importance of the developed methodology was realized by the synthesis of indoloquinolones and N-((1H-indol-3-yl)methyl)aniline and by a single-step gram-scale synthesis of the naturally occurring cephalandole A analogue.Item Iodine(iii)-promoted regioselective and efficient synthesis of β-triazolyl BODIPYs for the selective recognition of nickel ions and bovine serum albumin(RSC, 2022) Kumar, Dalip; Sarkar, MadhushreeVarious β-triazolyl tethered BODIPYs were efficiently prepared in a sequential one-pot protocol involving the initial reaction of BODIPY with iodobenzene diacetate (IBD) and sodium azide to in situ generate BODIPY azides followed by a copper-catalyzed azide–alkyne cycloaddition reaction. Under the optimized reaction conditions, various β-triazolyl BODIPYs 5a–i were successfully prepared in good yields and adequately characterized by using UV, NMR, mass spectral data and XRD analyses. The UV-Visible spectra of the prepared β-triazolyl BODIPYs 5a–i showed intense absorption bands (514–545 nm) with a 13–44 nm red shift when compared with those of the parent BODIPY. The selective recognition of compound 5d towards Ni2+ ions (detection limit 0.26 nM) led to significant quenching in the fluorescence intensity over other selected bivalent metal ions. The complex formed between 5d and Ni2+ in a stoichiometry of 2 : 1 was found to have a binding constant of 7.5 × 105 M−1. The fluorescence of compound 5i gets enhanced gradually upon interaction with bovine serum albumin due to its selective and high binding affinity (1.25 × 105 M−1) with protein and a concomitant decrease in the total non-radiative decay rate