@article { ISI:000263749400010, title = {Efficient, rapid, and regioselective bromination of anilines and phenols with 1-butyl-3-methylpyridinium tribromide as a new reagent/solvent under mild conditions}, journal = {Tetrahedron Letters}, volume = {50}, number = {9}, year = {2009}, month = {MAR}, pages = {1007-1009}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

1-Butyl-3-methylpyridinium tribromide, [BMPy]Br(3) proves to be a highly efficient, regioselective reagent/solvent for nuclear bromination of various anilines and phenols. The synthesis and characterization of the room temperature ionic liquid [BMPy]Br(3) (2) is described. The bromination was carried out in the absence of organic solvents and in most cases the only extraction solvent needed was water. The spent 1-butyl-3-methylpyridinium bromide (1) was easily recycled. (C) 2008 Elsevier Ltd. All rights reserved.

}, keywords = {Bromination, Ionic liquid, Regioselective, [BMPy]Br(3)}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2008.12.053}, author = {Borikar, Sanjay P. and Daniel, Thomas and Paul, Vincent} } @article { ISI:000274424100003, title = {Mild, efficient, and regioselective monobromination of arylamines and phenols using [BBIm]Br-3 as a new reagent}, journal = {Synthetic Communications}, volume = {40}, number = {5}, year = {2010}, month = {APR}, pages = {PII 919083074}, publisher = {TAYLOR \& FRANCIS INC}, address = {325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA}, abstract = {

We report here an efficient method for the synthesis and characterization of the room-temperature ionic liquid 1,3-di-n-butylimidazolium tribromide ([BBIm]Br-3) (2) and its application as an efficient reagent and solvent for regioselective bromination of arylamines and phenols under mild conditions. The bromination was carried out in the absence of organic solvents, and in most cases, the only extraction solvent needed was water. The spent 1,3-di-n-butylimidazolium bromide (1) was easily recycled.

}, keywords = {Ionic liquid, monobromination, Regioselective, Solvent-free, [BBIm]Br3}, issn = {0039-7911}, doi = {10.1080/00397910903009430}, author = {Borikar, Sanjay P. and Daniel, Thomas and Paul, Vincent} } @article { ISI:000343624300030, title = {First iodocyclization reaction of allene-thioureas: an efficient approach to bicyclic beta-lactams}, journal = {Tetrahedron Letters}, volume = {55}, number = {43}, year = {2014}, month = {OCT}, pages = {5998-6000}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

The regioselective iodocyclization reaction of allene-thioureas is described, for the first time, for the synthesis of bicyclic beta-lactams. The substitution at the allenyl part heavily influenced the iodocyclization reaction. The iodocyclization reaction of the unsubstituted allene-thioureas afforded six-membered 3-thia-1-dethiacephems whereas, the substituted allene-thiourea afforded seven-membered thiazepines along with five-membered isopenams. (C) 2014 Elsevier Ltd. All rights reserved.

}, keywords = {Allene, beta-Lactams, Iodocyclization, Regioselective, thiourea}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2014.09.004}, author = {Garud, Dinesh R. and Jadhav, Amol R. and Lahore, Santosh V. and Kahar, Nilesh M. and Joshi, Rohini R. and Joshi, Ramesh A. and Koketsu, Mamoru} } @article { ISI:000366209800015, title = {Synthesis of 3-Thia-1-dethiacephems via Regioselective Iodocyclization Reaction}, journal = {Synthesis-Stuttgart}, volume = {47}, number = {24}, year = {2015}, month = {DEC}, pages = {3956-3962}, publisher = {GEORG THIEME VERLAG KG}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

The key N-homopropargylthiourea intermediates, N-substituted 2-oxo-4-propargylazetidine-1-carbothioamides, were prepared by the reaction of a 4-propargylazetidin-2-one with isothiocyanates. Bicyclic -lactams, i.e. 3-thia-1-dethiacephems, were prepared via highly regioselective iodocyclization reaction of N-substituted 2-oxo-4-propargylazetidine-1-carbothioamides with molecular iodine at room temperature in moderate to excellent yields. A variety of functional groups were well tolerated under the reaction conditions.

}, keywords = {-lactams, 3-thia-1-dethiacephems, Iodocyclization, Regioselective, thiourea}, issn = {0039-7881}, doi = {10.1055/s-0035-1560350}, author = {Garud, Dinesh R. and Rode, Navnath D. and Bathe, Sagar R. and Ranpise, Vinod S. and Joshi, Ramesh A. and Joshi, Rohini R. and Koketsu, Mamoru} } @article { ISI:000365050700016, title = {Sol-gel synthesised WO3 nanoparticles supported on mesoporous silica for liquid phase nitration of aromatics}, journal = {Applied Catalysis B-Environmental}, volume = {182}, year = {2016}, month = {MAR}, pages = {142-152}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A series of WO3/SiO2 catalysts have been prepared by sol-gel method using ammonium metatungstate and ethyl silicate-40 (ES-40) as WO3 and SiO2 precursors respectively. The sol-gel method has led to the formation of WO3 nano-particles of 2-5 nm well dispersed on mesoporous silica along with some WO3{\textquoteright} agglomerates. Formation of monoclinic WO3 was seen on the catalysts above 5 wt\% WO3 loading by XRD analysis. Silica has shown very high surface area of 606 m(2)/g which decreased gradually upto 368 m(2)/g with 20 wt\% WO3 loading. 20 wt\% WO3/SiO2 catalyst has shown maximum acidity (0.56 mmol NH3/g) with presence of both Lewis and Bronsted acidity. UV-vis DRS analysis showed formation of polytungstate species along with WO3 on silica surface. The prepared catalysts were used for liquid phase nitration of aromatics using 70\% nitric acid as nitrating agent without using any sulfuric acid. Very high conversion (99\%) was obtained for p-cresol nitration with very high selectivity (99\%) for 2-nitro p-cresol. The water formed during the reaction was removed azeotropically using ethylene dichloride as solvent. In case of o-xylene 74\% conversion was obtained with 54\% selectivity for 4-nitro o-xylene. The effect of different WO3 precursors on nitration efficiency was studied using sodium tungstate and tungstic acid as precursors. However,ammonium metatungstate showed the highest acidity. Sodium tungstate showed formation of dimer of sodium tungstate which did not show any acidity and hence no activity for nitration. The mechanism for nitration using WO3/SiO2 has been proposed based on polarisation of water on tungsten centre generating Bronsted acidity which can further generate nitronium ion giving subsequently nitration of the aromatic ring. (C) 2015 Elsevier B.V. All rights reserved.

}, keywords = {Aromatic nitration, heterogeneous catalysis, Regioselective, Sol-gel synthesis, Water polarization}, issn = {0926-3373}, doi = {10.1016/j.apcatb.2015.09.020}, author = {Kulal, A. B. and Dongare, Mohan K. and Shubhangi B. Umbarkar} } @article {44591, title = {"Metal-free{\textquoteright}{\textquoteright} synthesis of 1,2,3-triazoles via tandem azidation, intramolecular [3+2]-cycloaddition and aromatization of ethyl acrylate derivatives}, journal = {Tetrahedron Letters}, volume = {59}, year = {2018}, month = {JUN }, pages = {2365-2367}, abstract = {

An efficient {\textquoteleft}{\textquoteleft}one-pot{\textquoteright}{\textquoteright} method for the synthesis of substituted 1,2,3-triazole derivatives in excellent yields as single regioisomer is reported. The key transformation involves an atom-efficient tandem azidation, intramolecular [3+2]-cycloaddition and aromatization of acrylate derivatives on treatment with NaN3 in DMF under mild conditions. (C) 2018 Elsevier Ltd. All rights reserved.

}, keywords = {Intramolecular cycloaddition, Regioselective, Tandem azidation, triazoles}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2018.05.020}, author = {Kumar, B. Senthil and Gadakh, Sunita and Sudalai, Arumugam} } @article {46952, title = {Catalyst-free regioselective [3+2] cycloadditions of alpha,beta-unsaturated N-arylnitrones with alkenes to access functionalized isoxazolidines: a DFT study}, journal = {Chemistry-An Asian Journal}, volume = {15}, year = {2020}, month = {MAR}, pages = {899-903}, type = {Article}, abstract = {

The catalyst-free regioselective [3+2]-cycloaddition of alpha,beta-unsaturated N-arylnitrones with alkenes are developed. The series of synthetically important functionalized isoxazolidines are prepared in good to excellent yields by step economic pathway under ligand and transition-metal-free conditions. The regioselective cycloaddition pathway supported by control experiment and computational study.

}, keywords = {DFT study, isoxazolidines, metal and ligand free, nitrone cycloaddition, Regioselective}, issn = {1861-4728}, doi = {10.1002/asia.201901754, Early Access Date = FEB 2020}, author = {Ghosh, Arnab and Mane, Manoj V. and Rode, Haridas B. and Patil, Siddappa A. and Sridhar, Balasubramanian and Dateer, Ramesh B.} }