@article { ISI:000240554000009, title = {Ionic liquid promoted facile one-pot synthesis of 1-pyridylimidazo[1,5-a]pyridines from dipyridylketone and aryl aldehydes}, journal = {Synthesis-Stuttgart}, number = {17}, year = {2006}, month = {SEP}, pages = {2849-2854}, publisher = {GEORG THIEME VERLAG KG}, type = {Article}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

A highly efficient one-pot methodology has been developed to synthesize a class of substituted 1-pyridylimidazo[ 1,5-a]pyridines, using Bronsted acidic ionic liquid 1-butylimidazolium tetrafluoroborate, [Hbim]BF4 in excellent isolated yields in the absence of any catalyst. The methodology is characterized by simple work-up procedures along with efficient recovery and recycling of the ionic liquid, which acts as a reaction medium as well as a promoter.

}, keywords = {5-a]pyridines, Aldehyde, ammonium acetate, heterocycles, imidazo[1, ionic liquids}, issn = {0039-7881}, doi = {10.1055/s-2006-942522}, author = {Siddiqui, Shafi A. and Potewar, Taterao M. and Lahoti, Rajgopal J. and Srinivasan, Kumar V.} } @article { ISI:000260411100014, title = {Efficient and eco-friendly synthesis of 2-amino-1,3-selenazoles in an ionic liquid/water system under ambient conditions}, journal = {Arkivoc}, number = {12}, year = {2008}, month = {JAN}, pages = {117-125}, publisher = {ARKAT USA INC}, type = {Article}, address = {C/O ALAN R KATRITZKY, UNIV FLORIDA, DEPT CHEMISTRY, PO BOX 117200, GAINESVILLE, FL 32611 USA}, abstract = {

An efficient and eco-friendly synthesis of 2-amino-1,3-selenazoles in ionic liquid/water solvent system is described. The paper describes synthesis of 2-amino-1,3-selenazoles by condensation of various phenacyl bromide with selenourea under ambient conditions in short reaction times. This protocol has notable advantages such as the absence of any added catalyst, simple operation and excellent yields of products and recyclability of the ionic liquid.

}, keywords = {2-Amino-1, 3-selenazoles, ambient conditions, heterocycles, ionic liquid/water system, selenoureas, substituted phenacyl bromide}, issn = {1551-7004}, author = {Potewar, Taterao M. and Ingale, Sachin A. and Srinivasan, Kumar V.} } @article { ISI:000296195400018, title = {Phosphine-mediated synthesis of 1,4-oxazepine- and 1,5-oxazocine-based sugar hybrids from deoxysugar azides}, journal = {Synthesis-Stuttgart}, volume = {21}, number = {21}, year = {2011}, month = {NOV}, pages = {3523-3529}, publisher = {GEORG THIEME VERLAG KG}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

An efficient and convenient method was developed for the synthesis of novel 1,4-oxazepine- and 1,5-oxazocine-based sugar hybrids from readily available deoxysugar azides by means of tributylphosphine-mediated tandem reactions. The resulting glycoconjugates might be useful in increasing the diversity of sugar backbones, and could find applications as potential glycomimetics and in drug discovery.

}, keywords = {Alkynes, azides, carbohydrates, heterocycles, oxazepines, oxazocines, Tandem reactions}, issn = {0039-7881}, doi = {10.1055/s-0030-1260218}, author = {Kurhade, Suresh E. and Salunkhe, Videsh T. and Siddaiah, V. and Bhuniya, Debnath and Reddy, D. Srinivasa} } @article { ISI:000290787100020, title = {Regioselective monoalkylation of dimethyl alkylidenesuccinates: simple approach to dialkyl-substituted maleic anhydrides including chaetomellic acid A}, journal = {Synthesis-Stuttgart}, number = {11}, year = {2011}, month = {JUN}, pages = {1804-1808}, publisher = {GEORG THIEME VERLAG KG}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

Natural and nonnatural dialkylmaleic anhydrides were readily prepared from dimethyl alkylidenesuccinates by sodium hexamethyldisilazide-induced selective monoalkylation followed by base-catalyzed hydrolysis.

}, keywords = {alkylations, Esters, furans, heterocycles, maleic anhydrides}, issn = {0039-7881}, doi = {10.1055/s-0030-1260013}, author = {Kshirsagar, Umesh A. and N. P. Argade} } @article {44627, title = {Copper- and phosphine-free nickel(II)-catalyzed method for C-H bond alkynylation of benzothiazoles and related azoles}, journal = {Asian Journal of Organic Chemistry}, volume = {7}, year = {2018}, month = {JUL}, pages = {1390-1395}, abstract = {

A phosphine-free nickel(II)-catalyzed method for the C(2)-H bond alkynylation of (benzo)thiazoles, (benz)imidazoles, and oxazoles is described. Well-defined and air-stable (Phen)NiCl2 catalyst efficiently catalyzes the coupling of diverse azoles with alkynyl bromides without the use of a copper co-catalyst, and the method tolerates synthetically important functional groups. Preliminary mechanistic studies on this Ni-II-catalyzed alkynylation emphasize the homogeneous nature of the catalyst, and rule out a radical manifold for the reaction. The synthetic utility of this Ni-catalyzed method is demonstrated by further functionalizing the alkynylated benzothiazoles to 3-methyl-2-(alkynyl)benzo[d]thiazolium salts that are known DNA cleaving agents.

}, keywords = {alkynylation, azoles, C-H activation, heterocycles, Nickel}, issn = {2193-5807}, doi = {10.1002/ajoc.201800243}, author = {Patel, Ulhas N. and Punji, Benudhar} } @article {47156, title = {[8+3]-cycloaddition of tropones with azaoxyallyl cations}, journal = {Chemistry-An Asian Journal}, volume = {14}, year = {2019}, month = {DEC }, pages = {4748-4753}, type = {Article}, abstract = {

Although azaoxyallyl cations are widely used as 1,3-dipoles for various cycloaddition reactions leading to nitrogen-containing heterocycles, their application in higher-order cycloaddition reaction remains scarce. Herein, we present the [8+3]-cycloaddition reaction of tropones with in situ generated azaoxyallyl cations allowing the one-step construction of cycloheptatriene-fused 1,4-oxazinones in moderate to good yields. This base-promoted new carbon-oxygen and carbon-nitrogen bond-forming reaction takes place under mild conditions in the absence of transition metal catalysts.

}, keywords = {1, 4-oxazinones, azaoxyallyl cations, heterocycles, tropones, [8+3] cycloaddition}, issn = {1861-4728}, doi = {10.1002/asia.201901198}, author = {Roy, Tony and Jacob, Anu and Bhattacharjee, Subrata and Biju, Akkattu T.} } @article {46046, title = {Steroidal thiazolidinone derivatives: design, synthesis and their molecular interaction with human serum albumin}, journal = {Steroids}, volume = {148}, year = {2019}, month = {AUG}, pages = {99-113}, type = {Article}, abstract = {

A series of steroidal thiazolidinone derivatives have been synthesized through one-pot multicomponent reaction involving steroidal ketone, thiosemicarbazide/methyl-thiosemicarbazide and DMAD in presence of AlCl3 as a Lewis acid catalyst. Among all the synthesized steroidal thiazolidinone derivatives, compound 7-9 (ST 7-9) were investigated for their in vitro molecular interaction with human serum albumin. Intrinsic fluorescence spectroscopy, constant wavelength synchronous fluorescence spectroscopy, circular dichroism and UV-visible absorption techniques have been exploited to characterize the binding phenomena in phosphate buffer solution at pH 7.4. The experimental results indicated that ST 7-9 bind to HSA and the intrinsic fluorescence of HSA was quenched through static quenching mechanism. The binding parameters were calculated and the binding constants obtained were 1.44 x 10(5) M-1 for ST 7, 0.84 x 10(5) M-1 for ST 8 and 1.06 x 10(5) M-1 for ST 9. Circular dichroism analysis confirms that the presence of ST 7-9, altered the secondary structure of HSA due to partial unfolding of the polypeptide chain. Furthermore, hemolytic activity assay demonstrated that the synthesized steroidal thiazolidinone derivatives have good compatibility towards human red blood cells. Finally, molecular docking studies revealed that the steroidal thiazolidinones can bind in the hydrophobic cavity of HSA, by hydrophobic and hydrogen bonding interaction. These results provided valuable information about the binding mechanism of ST 7-9 with HSA and play a pivotal role in the development of steroidal heterocycle inspired compounds.

}, keywords = {heterocycles, Human serum albumin, steroids, Thiazolidinone}, issn = {0039-128X}, doi = {10.1016/j.steroids.2019.02.015}, author = {Ansari, Anam and Ali, Abad and Asif, Mohd and Shamsuzzaman} } @article {46673, title = {Expeditious and solvent-free nickel-catalyzed c-h arylation of arenes and indoles (vol 10, pg 2242, 2017)}, journal = {ChemSusChem}, volume = {13}, year = {2020}, month = {NOV }, pages = {5771}, type = {Correction}, keywords = {Arylation, C-H activation, heterocycles, Homogeneous catalysis, Nickel}, issn = {1864-5631}, doi = {10.1002/cssc.202002313, Early Access Date = OCT 2020}, author = {Jagtap, Rahul A. and Soni, Vineeta and Punji, Benudhar} } @article {47582, title = {Catalytic applications of hydrotalcite and related materials in multi -component reactions: concepts, challenges and future scope}, journal = {Sustainable Chemistry and Pharmacy}, volume = {22}, year = {2021}, month = {SEP}, pages = {100458}, type = {Article}, abstract = {Hydrotalcites (HTs) are the potential substitute to conventional base catalysts. HTs are useful in efficient syntheses of various heterocycles, such as chromenes, pyrans, pyrazoles, triazoles, using multi-component reactions. This review focuses on the chemistry of HTs and particularly hydrotalcites and related materials in the synthesis of heterocycles. The effects of preparation method and, physico-chemical parameters, such as calcination, molar ratio of metals, role of intercalated ions, surface area, on the catalytic activities are discussed. Along with technical aspects, this review also unlocks various untouched areas in developing sustainable catalyst for syntheses of heterocycles, drugs, etc. for the future.}, keywords = {green chemistry, green synthesis, heterocycles, heterogeneous catalysis, hydrotalcite, Metal Oxide}, doi = {10.1016/j.scp.2021.100458}, author = {Burange, Anand S. and Gopinath, Chinnakonda S.} } @article {47413, title = {Green synthesis of xanthene and acridine-based heterocycles of pharmaceutical importance: a review}, journal = {Environmental Chemistry Letters}, year = {2021}, month = {MAR}, type = {Review; Early Access}, abstract = {

Xanthene and acridine-based heterocyclic compounds find applications in cancer chemotherapy, biological staining and laser dyes and are known for their antibacterial and anti-tumor properties. Here we review green catalytic routes for the synthesis of 1,8-dioxo-octahydroxanthenes, 1,8-dioxo-decahydroacridines and related heterocyclic molecules with catalysts such as metal oxides, mixed metal oxides, resins, supported organocatalysts, heteropolyacids, carbon-based materials, zeolites, sulfides and ionic liquids. We compare protocols for their catalytic activities, and proposed mechanisms are discussed.

}, keywords = {green chemistry, heterocycles, heterogeneous catalysis, Metal oxides, nanocatalysis}, issn = {1610-3653}, doi = {10.1007/s10311-021-01223-w, Early Access Date = MAR 2021}, author = {Burange, Anand S. and Gadam, Komal G. and Tugaonkar, Prajyot S. and Thakur, Seema D. and Soni, Ravish K. and Khan, Rubej R. and Tai, Mubashira S. and Gopinath, Chinnakonda S.} } @article {49125, title = {Advances in the iron-catalyzed direct functionalizations of heterocycles}, journal = {Synlett}, volume = {34}, year = {2023}, month = {APR}, pages = {683-697}, type = {Article}, abstract = {

Direct functionalization of heterocycles is an advanced strategy for diversifying privileged and biorelevant heterocycle-containing molecules. Particularly, use of the most abundant transition metal, iron, as a catalyst makes this process highly cost-effective and sustainable. Recently, some progress has been realized towards the direct functionalization of heterocycles under iron catalysis. Herein, we present the developments in the C-H bond functionalizations and related reactions of various heterocycles by abundant iron salts. This Synpacts is categorized into different sections based on heterocycles being functionalized, and each section is discussed based on the type of reaction catalyzed by iron. 1 Introduction 2 Functionalization of Indoles 2.1 Alkylation 2.2 Alkenylation 2.3 Other Reactions 3 Oxindoles and isatins 3.1 C-C Bond Formation 3.2 C-Heteroatom Bond Formation 4 Pyridines and Furans 5 Functionalization of Azoles 6 Summary and Outlook

}, keywords = {Alkylation, azoles, C-H functionalization, heterocycles, indoles, iron, Mechanism}, issn = {0936-5214}, doi = {10.1055/a-1890-8503}, author = {Pradhan, Chandini and Punji, Benudhar} } @article {49190, title = {Chemodivergent dehydrogenative coupling of alcohols by 3d metal catalysts}, journal = {ChemCatChem}, volume = {16}, year = {2024}, month = {JUN }, type = {Article}, abstract = {

Chemodivergent synthesis by transition metal catalysts is a straightforward and sustainable approach to achieving valuable organic compounds. Especially, the chemodivergent dehydrogenative couplings of alcohols with organic motifs to develop various saturated and unsaturated compounds are highly environmentally benign due to the reduced waste generation. In this concept review, we presented the 3d transition metal (Mn, Fe, Co, and Ni)-catalyzed chemodivergent synthesis of imines and amines, saturated and unsaturated carbonyl/alcohol compounds, saturated and unsaturated nitriles, N-heterocycles, and N-/C-alkylated indoles. The discussed reaction commanded two or three different products with high chemoselectivity by changing specific reaction parameters, but keeping the catalyst unchanged. Generally, the acceptorless dehydrogenative coupling (ADC) provides unsaturated moieties, whereas the borrowing-hydrogen (BH) process results in saturated compounds. Text for Table of Contents: An overview of the chemodivergent dehydrogenative coupling of alcohols by the Earth-abundant transition metal catalysts is discussed. image

}, keywords = {3d metals, Alcohols, chemodivergent, dehydrogenative coupling, heterocycles}, issn = {1867-3880}, doi = {10.1002/cctc.202301558}, author = {Bansal, Sadhna and Punji, Benudhar} } @article {49228, title = {Divergent synthesis of unsymmetrical Bis-heteroaryl ketones via base-promoted cascade reactions of 1,2-alkynedione-derived N-propargylic β-enaminones}, journal = {JOURNAL OF ORGANIC CHEMISTRY}, volume = {89}, year = {2024}, month = {AUG }, pages = {11665-11670}, type = {Journal Article}, keywords = {ASYMMETRIC-SYNTHESIS, heterocycles, intramolecular cyclization, pyrroles}, issn = {0022-3263}, doi = {10.1021/acs.joc.4c01407}, author = {Bag, Debojyoti and Saini, Sheetal and Rathod, Mahesh S. and Sawant, Sanghapal D.} }