01494nas a2200253 4500008004100000022001400041245016900055210006900224260010600293300001400399490000700413520047800420653001300898653002000911653002500931653001700956653001700973653001800990100002601008700002101034700003101055700003001086856012401116 2014 eng d a0040-403900aHighly regioselective C4-hydrazinylation of 2,4-dichloroquinolines: expedient synthesis of aminoquinoline substituted pyrrolidin-2,5-diones via hydrazinylquinolines0 aHighly regioselective C4hydrazinylation of 24dichloroquinolines  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcJUL a4240-42440 v553 a

A new class of hydrazinylquinoline regio-isomers has been synthesized through SNAr reaction of 2,4-dichloroquinolines with hydrazine hydrate. The reaction stops at the mono-substitution product with high regioselectivity at the C-4 rather than C-2 position of dichloroquinolines. The hydrazinylquinolines were subsequently converted into aminoquinoline substituted pyrrolidin-2,5-diones in the presence of Eaton's reagent. (C) 2014 Elsevier Ltd. All rights reserved.

10a5-diones10aEaton's reagent10aHydrazinylquinolines10aPyrrolidin-210aRegioisomers10aSNAr reaction1 aKumar, Gopal, Senthil1 aZeller, Matthias1 aGonnade, Rajesh, Ghanshyam1 aPrasad, Kamam, Jayarampil uhttps://library.ncl.res.in/content/highly-regioselective-c4-hydrazinylation-24-dichloroquinolines-expedient-synthesis-001975nas a2200241 4500008004100000245012100041210006900162260000800231490000600239520110700245100002201352700002401374700001501398700002501413700002601438700002501464700002101489700003101510700003301541700001501574700002001589856012401609 2015 eng d00aSpirochromone-chalcone conjugates as antitubercular agents: synthesis, bio evaluation and molecular modeling studies0 aSpirochromonechalcone conjugates as antitubercular agents synthe cDEC0 v53 a

A new series of spirochromone annulated chalcone conjugates were synthesized and evaluated for their antitubercular activity against Mycobacterium tuberculosis H37Rv strain. These compounds were subjected to molecular modeling studies using docking and chemoinformatics based approaches. The docking simulations were performed against a range of known receptors for chalcone derived compounds to reveal MTB phosphotyrosine phosphatase B [MtbPtpB] protein as the most probable target based on the high binding affinity scores. Five compounds exhibit significant inhibition, showing minimum inhibitory concentration values i.e. MIC values ranging from 3.13–12.5 μg mL−1. Further analysis of the synthesized compounds with known and in-house developed chemoinformatics tools unequivocally established their potential as anti-tubercular compounds. QSAR modeling revealed a quantitative relationship between biological activities and frontier molecular orbital energies of synthesized compounds. The predictive model can be employed further for virtual screening of new compounds in this series.

1 aMujahid, Mohammad1 aPerumal, Yogeeswari1 aSriram, D.1 aBasavanag, U., M. V.1 aDıaz-Cervantes, Erik1 aCordoba-Bahena, Luis1 aRobles, Juvencio1 aGonnade, Rajesh, Ghanshyam1 aKarthikeyan, Muthukumarasamy1 aVyas, Renu1 aKrishnan, Muthu uhttps://library.ncl.res.in/content/spirochromone-chalcone-conjugates-antitubercular-agents-synthesis-bio-evaluation-and01711nas a2200193 4500008004100000245015800041210007000199260000800269300001600277490000700293520094900300100002301249700001701272700001701289700003101306700002701337700002201364856013101386 2017 eng d00aEnantioselective synthesis of spiro γ-butyrolactones by N-heterocyclic carbene (NHC)-catalyzed formal [3+2] annulation of enals with 3-hydroxy oxindoles0 aEnantioselective synthesis of spiro γbutyrolactones by Nheterocy cFEB a2013 - 20190 v163 aThe N-heterocyclic carbene (NHC)-catalyzed enantioselective formal [3 + 2] annulation of α,β-unsaturated aldehydes with 3-hydroxy oxindoles is presented. Under oxidative conditions using the bisquinone oxidant, the reaction resulted in the synthesis of spiro γ-butyrolactones in moderate to good yields, enantioselectivity and diastereoselectivity. The reaction likely proceeds via the generation of the NHC-bound α,β-unsaturated acylazolium intermediate from enals, which was intercepted by the dioxindoles in a formal [3 + 2] pathway to form the spirocyclic compounds. However, a deeper mechanistic investigation revealed that the reaction can also proceed via the homoenolate intermediate. In this case, the dioxindole was oxidized to the corresponding isatin derivative using traces of air under basic conditions, and was intercepted with the NHC-bound homoenolate intermediate in a formal [3 + 2] pathway to afford the spiro compound.1 aMukherjee, Subrata1 aJoseph, Sumi1 aBhunia, Anup1 aGonnade, Rajesh, Ghanshyam1 aReddy, Santhi, Vardhan1 aBiju, Akkattu, T. uhttps://library.ncl.res.in/content/enantioselective-synthesis-spiro-%CE%B3-butyrolactones-n-heterocyclic-carbene-nhc-catalyzed00889nas a2200169 4500008004100000245009200041210006900133260000800202300001500210490000700225520027800232100001800510700001900528700003100547700002800578856011300606 2017 eng d00aExploring the gem-dimethyl effect in the formation of imine-based macrocycles and cages0 aExploring the gemdimethyl effect in the formation of iminebased  cJUL a8721-8724 0 v173 aUsing the gem-dimethyl effect as a platform, a variety of organic [2+2] macrocycles and [2+3] cofacial cages was obtained in high yields. Imine-based macrocyclization could be performed even at high concentrations (0.5 to 1.0 M), via instant mixing of aldehydes and amines.1 aMadhu, Suresh1 aRashmi, E., V.1 aGonnade, Rajesh, Ghanshyam1 aSanjayan, Gangadhar, J. uhttps://library.ncl.res.in/content/exploring-gem-dimethyl-effect-formation-imine-based-macrocycles-and-cages01529nas a2200169 4500008004100000245010700041210006900148260000800217300001400225490000700239520088800246100002001134700003201154700001801186700003101204856012401235 2017 eng d00aGeneral nickel-catalyzed method for C-H bond alkynylation of heteroarenes through chelation assistance0 aGeneral nickelcatalyzed method for CH bond alkynylation of heter cFEB a2907-29140 v233 a

A general nickel-catalyzed method for the alkynylation of heteroarenes through monodentate chelation assistance is described. Many heterocycles, including indoles, pyrroles, imidazoles and pyrazole, efficiently coupled with (triisopropylsilyl)alkynyl bromide, and synthetically important functional groups, such as halides, ether, nitrile, nitro were tolerated. Synthetic applicability of this Ni-catalyzed method is demonstrated by the removal of triisopropylsilyl (-SiiPr₃) group, and further functionalization into triazolyl, benzofuranyl and alkynyl arene derivatives. Preliminary mechanistic investigations on the alkynylation of indole suggest that the reaction proceeds through kinetically relevant C-H activation and follows the two-electron redox pathway. A catalytically competent Ni-species, [(Phen)₃Ni].NiBr₄ has been isolated and structurally characterized.

1 aPunji, Benudhar1 aKhake, Shrikant, manmathapp1 aSoni, Vineeta1 aGonnade, Rajesh, Ghanshyam uhttps://library.ncl.res.in/content/general-nickel-catalyzed-method-c-h-bond-alkynylation-heteroarenes-through-chelation01208nas a2200193 4500008004100000245006200041210005600103260000800159300001600167490000700183520060300190100001700793700002300810700002200833700001800855700003100873700002200904856008800926 2017 eng d00aN - heterocyclic - carbene - catalyzed umpolung of imines0 aN heterocyclic carbene catalyzed umpolung of imines cMAR a2730 - 27340 v563 a

N-Heterocyclic carbene (NHC) catalysis has been widely used for the umpolung of aldehydes, and recently for the umpolung of Michael acceptors. Described herein is the umpolung of aldimines catalyzed by NHCs, and the reaction likely proceeds via aza-Breslow intermediates. The NHC-catalyzed intramolecular cyclization of aldimines bearing a Michael acceptor resulted in the formation of biologically important 2-(hetero)aryl indole 3-acetic-acid derivatives in moderate to good yields. The carbene generated from the bicyclic triazolium salt was found to be efficient for this transformation.

1 aPatra, Atanu1 aMukherjee, Subrata1 aDas, Tamal, Kanti1 aJain, Shailja1 aGonnade, Rajesh, Ghanshyam1 aBiju, Akkattu, T. uhttps://library.ncl.res.in/content/n-heterocyclic-carbene-catalyzed-umpolung-imines01256nas a2200169 4500008004100000245010300041210006900144260000800213300001600221520059600237100002500833700002200858700002100880700003100901700002800932856012600960 2017 eng d00aStructural insights into the hydrogen-bonding and folding pattern in ant-ant-pro-gly tetrapeptides0 aStructural insights into the hydrogenbonding and folding pattern cMAY a2944–29493 aIn this paper, we provide structural insights into the hydrogen-bonding and folding pattern in Ant-Ant-Pro-Gly tetrapeptides (Ant: anthranilic acid; Pro: proline; and Gly: glycine). Comparison of the C-terminal esters and their amide analogs revealed strikingly different H-bonding networks. Whereas the ester analogs displayed an open structure without terminal H-bonding interactions, the amide analogs showed a completely folded structure. Structural details were revealed by using a combination of X-ray crystal structure studies and NOE-based molecular dynamics (MD) simulation studies.1 aBaravkar, Sachin, B.1 aKotmale, Amol, S.1 aMobin, Samir, R.1 aGonnade, Rajesh, Ghanshyam1 aSanjayan, Gangadhar, J. uhttps://library.ncl.res.in/content/structural-insights-hydrogen-bonding-and-folding-pattern-ant-ant-pro-gly-tetrapeptides01649nas a2200157 4500008004100000245015400041210007000195260000800265300001400273490000700287520098800294100002101282700002501303700003101328856013201359 2017 eng d00aSynthesis of annulated bis-indoles through Au(I)/brønsted acid-catalyzed reactions of (1H-indol-3-yl)(aryl)methanols with 2-(arylethynyl)-1H-indoles0 aSynthesis of annulated bisindoles through AuIbrønsted acidcataly cDEC a863 - 8690 v153 aA general method to access annulated bis-indoles from (1H-indol-3-yl)(aryl)methanols and 2-(arylethynyl)-1H-indoles under the catalysis of the Ph3PAuOTf/Brønsted acid binary catalyst system has been developed. The reaction was found to proceed in a highly efficient manner and benefit from easy-to-make starting materials, broad substrate scope and operational simplicity. The potential of this method has also been exemplified for the synthesis of pyrrole-annulated indoles using 2-(phenylethynyl)-1H-indoles and phenyl(1H-pyrrol-2-yl)methanols. Furthermore, the use of a ternary catalyst system, involving PdCl2/Brønsted acid/Ph3PAuOTf catalysts, has been realized for the synthesis of annulated bis-indoles starting directly from 2-(phenylbuta-1,3-diyn-1-yl)aniline and (1H-indol-3-yl)(aryl)methanol. Mechanistically, this reaction is very interesting since the overall process involves three different catalytic cycles catalyzed by three different catalysts in a relay fashion.1 aPatil, Nitin, T.1 aInamdar, Suleman, M.1 aGonnade, Rajesh, Ghanshyam uhttps://library.ncl.res.in/content/synthesis-annulated-bis-indoles-through-auibr%C3%B8nsted-acid-catalyzed-reactions-1h-indol-3