00772nas a2200193 4500008004100000245015200041210006900193260000800262300001600270490000700286100002200293700002000315700001700335700002300352700002200375700002400397700002100421856013600442 2016 eng d00aAu(I)/Ag(I) co-operative catalysis: interception of Ag-bound carbocations with α-gold(I) enals in the imino-alkyne cyclizations with N-allenamides0 aAuIAgI cooperative catalysis interception of Agbound carbocation cNOV a14462-144650 v521 aBagle, Pradip, N.1 aMane, Manoj, V.1 aVanka, Kumar1 aShinde, Dinesh, R.1 aShaikh, Samir, R.1 aGonnade, Rajesh, G.1 aPatil, Nitin, T. uhttps://library.ncl.res.in/content/auiagi-co-operative-catalysis-interception-ag-bound-carbocations-%CE%B1-goldi-enals-imino-alkyne01076nas a2200169 4500008004100000245016900041210006900210260000800279300001400287490000700301520038500308100002500693700002200718700002400740700002100764856012100785 2017 eng d00aIntramolecular ipso-arylative cyclization of aryl-alkynoates and N-arylpropiolamides with aryldiazonium salts through merged gold/visible light photoredox catalysis0 aIntramolecular ipsoarylative cyclization of arylalkynoates and N cAUG a9081-90840 v533 aA visible-light-promoted merged gold/photoredox catalyzed ipsoarylative cyclization has been reported. For instance, the reaction of aryl-alkynoates and N-arylpropiolamides with aryldiazonium salts in the presence of catalytic amounts of [(4-OCH3)C6H4](3)PAuCl and Ru(bpy)(3)(PF6)(2) under irradiation using a 32WCFL bulb gave arylated spirocarbocycles in moderate to good yields.1 aBansode, Avinash, H.1 aShaikh, Samir, R.1 aGonnade, Rajesh, G.1 aPatil, Nitin, T. uhttps://library.ncl.res.in/content/intramolecular-ipso-arylative-cyclization-aryl-alkynoates-and-n-arylpropiolamides01465nas a2200217 4500008004100000022001400041245012800055210006900183260000800252300001400260490000800274520068300282100002500965700002400990700002001014700002201034700002401056700002401080700002101104856012201125 2018 eng d a1523-706000aTotal synthesis and biological evaluation of cell adhesion inhibitors peribysin A and B: structural revision of peribysin B0 aTotal synthesis and biological evaluation of cell adhesion inhib cNOV a7003-70060 v 203 aTotal synthesis of potent cell-adhesion inhibitors peribysins A and B has been accomplished for the first time in racemic form. A Diels-Alder/aldol sequence to build the skeleton and decoration of the desired functionalities of the targeted natural products using highly stereoselective operations are the highlights. The structures of synthesized peribysins were fully characterized using spectral data and single-crystal X-ray analysis. Through this total synthesis, the initially proposed structure of peribysin B has been revised. Furthermore, the cell-adhesion inhibition potential of the scaffold (two peribysins + three analogues) was confirmed using anti-adhesion assay.1 aKalmode, Hanuman, P.1 aHandore, Kishor, L.1 aRajput, Raveena1 aShaikh, Samir, R.1 aGonnade, Rajesh, G.1 aKulkarni, Kiran, A.1 aReddy, Srinivasa uhttps://library.ncl.res.in/content/total-synthesis-and-biological-evaluation-cell-adhesion-inhibitors-peribysin-and-b02528nas a2200205 4500008004100000022001400041245016200055210006900217260000800286300001400294490000700308520174900315100002202064700002302086700001802109700001802127700002402145700002102169856013202190 2019 eng d a1528-748300aCrystal engineering for intramolecular pi-pi stacking: effect of sequential substitution of f on molecular geometry in conformationally flexible sulfonamides0 aCrystal engineering for intramolecular pipi stacking effect of s cOCT a5665-56780 v193 a

A small library of ten sulfonamide derivatives comprising two aromatic rings was synthesized to investigate the effect of chronological positioning of the F-atom on the intramolecular pi-stacking assembly. The sequential positioning of F atoms was carried out on one of the aromatic rings that is linked to the sulfonamide moiety directly while the other aromatic ring (phenyl or pyridine) is linked by an ethyl spacer with the sulfonamide moiety. The ethyl spacer is provided to achieve the required flexibility so that both aromatic rings can bend to acquire syn conformation facilitated pi-stacking between electron-deficient and electron-rich aromatic rings. The idea was to study the interplay between hydrogen bonding and pi-stacking synthons in the conformationally flexible sulfonamide derivatives. The solid-state conformation of all the derivatives was investigated using the single-crystal X-ray diffraction technique. Crystal structure analysis revealed that the syn conformation was achieved only in trifluoro and pentafluoro sulfonamide derivatives with benzene substitution while in all other derivatives the molecules take either midway or anti conformations. None of the sulfonamide molecules with a pyridine moiety showed syn conformation. It could be because of the involvement of the pyridine N-atom in the hydrogen bonding dimeric synthon. The molecular conformation study in solution state using 2D NOESY and HOESY NMR experiments also substantiated syn conformation in a pentafluoro sulfonamide molecule with benzene substitution. The conformational analysis carried out employing density functional theory (DFT) calculations confirmed higher stability for the syn conformation over midway and anti orientations.

1 aShaikh, Samir, R.1 aGawade, Rupesh, L.1 aKumar, Deepak1 aKotmale, Amol1 aGonnade, Rajesh, G.1 aStuerzer, Tobias uhttps://library.ncl.res.in/content/crystal-engineering-intramolecular-pi-pi-stacking-effect-sequential-substitution-f-molecular02441nas a2200265 4500008004100000022001400041245017700055210006900232260000900301300001600310490000600326520144600332653002401778653002201802653001701824653003101841653003501872100002401907700002201931700002401953700002001977700002201997700002502019856013102044 2019 eng d a2365-654900aCyanuric-chloride-mediated synthesis of 2-Aryl-3-tert-butoxycarbonyl-thiazolidine-4-carboxylic acid anilides: mechanistic, X-ray crystal structures and cytotoxicity studies0 aCyanuricchloridemediated synthesis of 2Aryl3tertbutoxycarbonylth cNOV  a12534-125460 v43 a

The `2R,4R'-2-aryl thiazolidine-4-carboxylic acid anilides (ATCAAs) were synthesized using cyanuric chloride (CC) as a clean and substoichiometric acid-amine coupling agent under optimized reaction conditions. The diesterphenol intermediate based mechanism is proposed and supported by spectral characterization of the intermediate. The single crystal X-ray structures of acid substrate (2R,4R)-3-(tert-butoxycarbonyl)-2-(2-methoxyphenyl)thiazolidine-4-carbox ylic acid (3 a) and anilides (R)-tert-butyl 4-(2-fluorophenylcarbamoyl)thiazolidine-3-carboxylate (4 b), (2R,4R)-tert-butyl 2-(2,6-dichlorophenyl)-4-(m-tolylcarbamoyl)thiazolidine-3-carboxylate (6 b) confirmed the formation of chiral anilides. The synthesized library of anilides [(R)-tert-butyl 4-Aryl thiazolidine-3-carboxylate and (2R,4R)-tert-butyl 2-Aryl-4-Aryl thiazolidine-3-carboxylate] 4 a-6 f was screened for their in vitro anti cancer, neuronal and neuroprotective studies. The anilides 4 b, 4 g, 5 d, 5 h, 6 c and 6 f (where the aryl=2-fluorophenylcarbamoyl, 4-chlorophenylcarbamoyl, 2-methoxyphenyl, 2,5-dichlorophenylcarbamoyl, 2,6-dichlorophenyl, 4-chlorophenylcarbamoyl respectively)were found to be less cytotoxic towards N2 A, SHSY-5Y neuronal cell lines in their differentiated and undifferentiated forms, and also exhibited dose dependant anti-inflammatory properties for a possible identification towards neurodegenerative and inflammatory disorders.

10aAcid-amine coupling10aCyanuric chloride10aCytotoxicity10aMechanistic investigations10aSingle crystal x-ray structure1 aJagtap, Rohidas, M.1 aShaikh, Samir, R.1 aGonnade, Rajesh, G.1 aRaheem, Shabnam1 aRizvi, Masood, A.1 aPardeshi, Satish, K. uhttps://library.ncl.res.in/content/cyanuric-chloride-mediated-synthesis-2-aryl-3-tert-butoxycarbonyl-thiazolidine-4-carboxylic00796nas a2200217 4500008004100000022001400041245012200055210006900177260000900246300001400255490000700269100001900276700003100295700002200326700001900348700001800367700001700385700002400402700002000426856013200446 2019 eng d a0897-475600aEfficient broad-band emission from contorted purely corner-shared one dimensional (1D) organic lead halide perovskite0 aEfficient broadband emission from contorted purely cornershared  cAPR  a2253-22570 v311 aBiswas, Anupam1 aBakthavatsalam, Rangarajan1 aShaikh, Samir, R.1 aShinde, Aparna1 aLohar, Amruta1 aJena, Satyam1 aGonnade, Rajesh, G.1 aKundu, Janardan uhttps://library.ncl.res.in/content/efficient-broad-band-emission-contorted-purely-corner-shared-one-dimensional-1d-organic-lead01150nas a2200217 4500008004100000022001400041245013000055210006900185260000900254300001200263490000700275520036900282100002200651700002000673700002700693700001900720700002200739700001800761700002100779856013200800 2019 eng d a1523-706000aGold(I)-catalyzed hydroxy group assisted C(sp(2))-H alkylation of enaminones with diazo compounds to access 3-alkyl chromones0 aGoldIcatalyzed hydroxy group assisted Csp2H alkylation of enamin cJAN  a335-3390 v213 a

A strategy for expedient synthesis of 3-substituted chromones from easily available o-hydroxyarylenaminones and diazo compounds has been developed. Carefully conducted experimental and computational studies led us to propose an uncommon mechanistic pathway involving the hydroxyl group assisted alkylation of enaminones with in situ generated gold carbenes.

1 aBagle, Pradip, N.1 aMane, Manoj, V.1 aSancheti, Shashank, P.1 aGade, Amol, B.1 aShaikh, Samir, R.1 aBaik, Mu-Hyun1 aPatil, Nitin, T. uhttps://library.ncl.res.in/content/goldi-catalyzed-hydroxy-group-assisted-csp2-h-alkylation-enaminones-diazo-compounds-access-302692nas a2200265 4500008004100000022001400041245009300055210006900148260000800217300001400225490000800239520180600247100003102053700002702084700002202111700001802133700002202151700002202173700002002195700002002215700002702235700002402262700002002286856012002306 2020 eng d a1932-744700aLigand structure directed dimensionality reduction (2D -> 1D) in lead bromide perovskite0 aLigand structure directed dimensionality reduction 2D 1D in lead cJAN a1888-18970 v1243 a

Low dimensional (2D, 1D) lead halide perovskites are currently attracting huge research interest due to their enabling properties. Demonstrating synthetic control on the dimensionality/ structure of these perovskites is highly challenging. Dimensionality in these perovskites is largely dictated by the nature/structure and composition of the incorporating ligands and the utilized synthetic conditions. Here, we demonstrate chemical composition based control on reduction of dimensionality (2D -> 1D) for lead bromide perovskite utilizing 2-(2-aminoethyl)isothiourea dihydrobromide as a common precursor ligand (Isothio Bromide). Controlling the hydrothermal reaction parameters (temperature, time) at a fixed precursor ratio affords corner-shared, contorted 2D sheet perovskite and corner-shared, contorted, chiral 1D chain perovskite. Such dimensionality reduction leads to contrasting photophysical properties: 1D chain perovskite shows long-lived and self-trapped broad band emission, whereas 2D perovskite shows short-lived, band edge emission with a long tail. Mechanistic studies and single crystal structure analysis reveal the incorporation of the utilized precursor ligand (Isothio Bromide) in 2D perovskite. Surprisingly, the 1D perovskite is found to be chiral (P2(1) space group) incorporating 2-(2-aminoethyldisulfanyl)ethanamine and ammonium ions as the achiral ligands generated in situ due to hydrothermal cleavage of the precursor (Isothio Bromide) ligand. Such structural and compositional change of the ligands, which manifests a different hydrogen bonding network in the resultant perovskite structure, plays a decisive role in dictating the final molecular formula and dimensionality/structure of the perovskite which largely controls their photophysical properties.

1 aBakthavatsalam, Rangarajan1 aHaris, Muhammed, P. U.1 aShaikh, Samir, R.1 aLohar, Amruta1 aMohanty, Ashutosh1 aMoghe, Dhanashree1 aSharma, Shivani1 aBiswas, Chinmoy1 aRaavi, Sai, Santhosh K1 aGonnade, Rajesh, G.1 aKundu, Janardan uhttps://library.ncl.res.in/content/ligand-structure-directed-dimensionality-reduction-2d-1d-lead-bromide-perovskite02005nas a2200253 4500008004100000022001400041245007700055210006900132260000900201300001400210490000700224520117700231100002201408700002701430700002701457700002201484700002201506700002401528700002401552700002101576700002601597700002001623856010801643 2020 eng d a1144-054600aSynthesis and biological activity of imidazole based 1,4-naphthoquinones0 aSynthesis and biological activity of imidazole based 14naphthoqu cMAY  a6889-69010 v443 a

Design and development of drugs in multi-drug resistant (MDR) infections have been of growing interest. We report the syntheses, and antibacterial and antifungal activities of imidazole-based 1,4-naphthoquinones (I-1 to I-4; 1-alkyl-2-methyl-1H-naphtho[2,3-d]imidazole-4,9-dione (alkyl = methyl to butyl)) and their precursors (B-3; N-(3-chloro-1,-dioxo-1,4-dihydronaphthalen-2-yl)acetamide) and A-1 to A-4; N-(3-(alkylamino)-1,4-dioxo-1,4-dihydronaphthalen-2-yl)acetamide (alkyl = methyl to butyl). Crystal structures of B-3, A-1 to A-3 and I-2 to I-4 were obtained through single crystal X-ray diffraction experiments. Electronic structure and charge distribution have further been characterized with the use of Density Functional Theory. Seven of these derivatives display a broad spectrum of antibacterial activity against few selected bacterial strains (Gram-positive and Gram-negative). As demonstrated MIC values with B-2 and B-3 against bacterial isolates were 8-64 mu g ml(-1) and those against pathogenic yeast, C. albicans, were observed in the range of 128-256 mu g ml(-1). MIC data of these derivatives suggest them to be promising against pathogens.

1 aChoudhari, Dinkar1 aSalunke-Gawali, Sunita1 aChakravarty, Debamitra1 aShaikh, Samir, R.1 aLande, Dipali, N.1 aGejji, Shridhar, P.1 aRao, Pradeep, Kumar1 aSatpute, Surekha1 aPuranik, Vedavati, G.1 aGonnade, Rajesh uhttps://library.ncl.res.in/content/synthesis-and-biological-activity-imidazole-based-14-naphthoquinones03387nas a2200193 4500008004100000245021900041210007100260260000800331300001400339490000700353520256500360100002202925700002302947700002202970700002102992700001703013700002403030856013903054 2024 eng d00aCrystal engineering for intramolecular π-π stacking: effect of substitution of electron-donating and electron-withdrawing groups on the molecular geometry in conformationally flexible Sulfoesters and sulfonamides0 aCrystal engineering for intramolecular ππ stacking effect of sub cJUL a3557-35730 v263 a

A series of 21 sulfoester and sulfonamide derivatives comprising two aromatic rings was synthesized to investigate the effect of the presence of either electron-donating (ED) or electron-withdrawing (EW) groups on the intramolecular pi-stacking assembly. The positioning of ED or EW moieties was carried out directly on one of the aromatic rings linked to the sulfonyl or sulfonamide moieties. In contrast, the other aromatic ring (phenyl or pyridine) was connected by a -CH2-CH2- spacer with the sulfonyl or sulfonamide moiety. The purpose of having an ethyl spacer between the two aromatic rings was to achieve conformational flexibility, facilitating the intramolecular pi-stacking assembly between the two aromatic rings. The use of sulfoester/sulfonamide groups allowed more conformational flexibility to attain desired orientations in solids with the interplay of the hydrogen-bonding interactions. Between the two functional groups, sulfonamides offered a more hydrogen-rich environment due to the amine moiety and may exhibit higher H-bonding propensity than the sulfoester moiety. The central idea here was to study the interplay between the hydrogen-bonding and pi & ctdot;pi interactions. The substituent groups chosen were categorized as strong electron-withdrawing (-CF3 and -CN), weak electron-withdrawing (-Cl and -Br), neutral (-H), and good electron-donating (-CH3 and -OCH3) groups. Crystal structure analysis revealed the syn conformation for all the derivatives, enabling intramolecular pi & ctdot;pi interactions between the two aromatic rings, whereas in the sulfonamide derivatives, the molecule takes either midway or anti conformations, except for one pyridine sulfonamide derivative, which showed the syn orientation but lacked intramolecular pi-stacking interactions. The absence of any conventional H-bond forming functional groups in the sulfoester derivatives may have resulted in the syn geometry facilitated by intramolecular pi-stacking interactions. Conversely, H-bond-forming functional groups in the sulfonamide derivatives could have prevented the syn conformation. The conformational analysis carried out employing density functional theory (DFT) calculations confirmed the higher stability of the syn conformation over the midway and anti orientations. The placing of electron-withdrawing and electron-donating groups at the para position of the benzene revealed sulfoesters preferably adopts a syn geometry facilitating the intramolecular pi-stacking, but sulphonamides takes midway or anti-geometry.

1 aShaikh, Samir, R.1 aGawade, Rupesh, L.1 aDabke, Niteen, B.1 aDash, Soumya, R.1 aVanka, Kumar1 aGonnade, Rajesh, G. uhttps://library.ncl.res.in/content/crystal-engineering-intramolecular-%CF%80-%CF%80-stacking-effect-substitution-electron-donating-and