01957nas a2200253   4500008004100000022001400041245007900055210006900134260007400203300001200277490000700289520102700296653001801323653003701341653002301378653004501401100002401446700002501470700002801495700002501523700002201548700002201570856011101592       2016                        eng d  a0928-070700aSynthesis and characterization of superhydrophobic-superoleophilic surface0 aSynthesis and characterization of superhydrophobicsuperoleophili  aVAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDSbSPRINGERcJUN  a475-4810 v783 a<p>The binary superhydrophobic-superhydrophilic surface has been successfully achieved by a combination of nanoscale texture roughness on micro-textured cotton thread network by layer-by-layer deposition method through the single-step sol-gel route. Furthermore, microstructures with improved wettability were produced, in which silica nanotextures were grown without modifying the chemical method to form superoleophilic and superhydrophobic networks. A superoleophilic surface (oil contact angle 0A degrees) and a superhydrophobic coated cotton fabric with surface free energy of gamma (total) = 13. 23 +/- A 0.37 mJ m(-2) (water contact angle of 167 +/- A 1A degrees and a small sliding angle of 4 +/- A 1A degrees) were successfully obtained. The results were exemplified here by the creation of immiscible oils separation membranes, and the innumerable applications of this technology also include self-cleaning fabrics, antistaining fabrics, water purification, and antiwetting fabrics for military applications.</p>10acontact angle10aLayer-by-layer deposition method10asol-gel processing10aSuperhydrophobic-superoleophilic surface1 aMahadik, Satish, A.1 aPedraza, Fernado, D.1 aRelekar, Brahmanand, P.1 aParale, Vinayak., G.1 aLohar, Gaurav, M.1 aThorat, Sagar, S.  uhttps://library.ncl.res.in/content/synthesis-and-characterization-superhydrophobic-superoleophilic-surface01435nas a2200181   4500008004100000245008000041210006900121260000800190300001200198490000700210520081100217100002401028700001601052700002401068700002801092700002201120856011101142       2017                        eng d00aBiocompatible superhydrophobic coating material for biomedical applications0 aBiocompatible superhydrophobic coating material for biomedical a  cMAR  a791-7960 v813 aBiomaterials and wettability have played a crucial role in the biocompatibility with a host matrix of body fluid and cells. We discuss designing superhydrophobic biomaterials for novel applications such as temporally implant, contact lenses, controlled drug release coatings, coating on medical instruments, etc. Such Superhydrophobic coating surfaces were created with the simple dip coating method by single step base catalyst sol-gel method. Methyltriethoxysilane/trimethoxymethylsilane-based deposition at different dip periods introduces interesting properties in the region, including superhydrophobicity, biocompatibility and transparency. This works reveal the impact of interaction bone marrow mesenchymal stem cells and surface free energy on the biocompatibility of superhydrophobic biomaterial.1 aMahadik, Satish, A.1 aPedraza, F.1 aMahadik, Sarika, S.1 aRelekar, Brahmanand, P.1 aThorat, Sagar, S.  uhttps://library.ncl.res.in/content/biocompatible-superhydrophobic-coating-material-biomedical-applications01105nas a2200181   4500008004100000245013000041210006900171260000800240300001400248490000700262520040700269100002600676700002200702700002800724700002400752700002200776856012500798       2017                        eng d00aLewis acid catalyzed cascade annulation of alkynols with alpha-ketoesters: a facile access to gamma-spiroketal-gamma-lactones0 aLewis acid catalyzed cascade annulation of alkynols with alphake  cJUN  a6641-66440 v533 aA novel Lewis acid catalyzed intermolecular cascade annulation of alkynols with alpha-ketoesters has been developed. This simple and efficient cascade annulation proceeds through a 5-exo-dig cyclization of alkynols followed by annulation with alpha-ketoester to provide a wide variety of unsaturated gamma-spiroketal-gamma-lactones (1,6-dioxaspiro[4.4]non-3-en-2-ones) related to many natural products.1 aKambale, Digambar, A.1 aThorat, Sagar, S.1 aPratapure, Madhukar, S.1 aGonnade, Rajesh, G.1 aKontham, Ravindar  uhttps://library.ncl.res.in/content/lewis-acid-catalyzed-cascade-annulation-alkynols-alpha-ketoesters-facile-access-gamma01169nas a2200169   4500008004100000022001400041245006100055210005600116260000800172300001400180490000600194520064500200100002200845700002300867700002200890856008700912       2018                        eng d  a2470-134300aFour-step total synthesis of (+)-yaoshanenolides A and B0 aFourstep total synthesis of yaoshanenolides A and B  cJUN  a7036-70450 v33 a<p>A highly concise bioinspired four-step total synthesis of yaoshanenolides A and B possessing tricyclic spirolactone with an unusual 5'H-spiro-[bicyclo[2.2.2]-oct[2] ene-7,2'-furan]-5'-one scaffold is reported. This synthesis features high-yielding aldol-type addition of gamma-butyrolactone on to the aldehyde, exocyclic olefination of lactone derivative using Eschenmoser's salt, and highly facial-and endo-selective [4 + 2]-cycloaddition of fully functionalized 5-methylene-2(5H)-furanone with natural R-(-)-alpha-phellandrene. The approach allows access to yaoshanenolides A and B in four linear steps in 11 and 13% overall yield.</p>1 aThorat, Sagar, S.1 aPalange, Megha, N.1 aKontham, Ravindar  uhttps://library.ncl.res.in/content/four-step-total-synthesis-yaoshanenolides-and-b01154nas a2200169   4500008004100000022001400041245013300055210006900188260000900257300001200266490000700278520050200285100002200787700002200809700002200831856013100853       2018                        eng d  a1523-706000aSynthesis of furo[2,3-b]pyran-2-ones through Ag(I)- or Ag(I)-Au(I)-catalyzed cascade annulation of alkynols and alpha-ketoesters0 aSynthesis of furo23bpyran2ones through AgI or AgIAuIcatalyzed ca  cFEB   a872-8750 v203 a<p>Ag(I)- or Ag(I)-Au(I)-catalyzed cascade annulation of alkynols (5-hexyn-1-ol systems) with a-ketoesters involving a dual activation process (pi and sigma) has been developed for the first time. This reaction proceeds through cycloisomerization of alkynol to give the 6-endo-enol ether followed by annulation with an alpha-ketoester to furnish furo[2,3-b]pyran-2-ones in good yields. Chemical structures of all products were rigorously confirmed by single crystal X-ray analysis and analogy.</p>1 aThorat, Sagar, S.1 aKataria, Priyanka1 aKontham, Ravindar  uhttps://library.ncl.res.in/content/synthesis-furo23-bpyran-2-ones-through-agi-or-agi-aui-catalyzed-cascade-annulation-alkynols01327nas a2200169   4500008004100000022001400041245007100055210006500126260000900191300001600200490000700216520076900223100002200992700002601014700002201040856009501062       2021                        eng d  a0022-326300aStereoselective total synthesis of (+/-)-pleurospiroketals A and B0 aStereoselective total synthesis of pleurospiroketals A and B  cOCT   a13572-135820 v863 aA full account of our efforts toward the stereoselective total synthesis of sesquiterpenoid-derived natural products (+/-)-pleurospiroketals A and B is described. Commercially available 3-methyl-2-cyclohexenone and 2,2-dimethyloxirane were used as key building blocks, and the substrate-controlled stereoselection was exploited to access the entire stereochemistry of these natural products. Initially, a planned synthetic route involving a [6,5]-bicyclic lactone intermediate was found to be insurmountable, and the later strategy comprising OsO4-NMO-mediated dihydroxylation of 3-methyl-2-cyclohexenone, followed by Luche reduction, Eschenmoser methylenation, and Bronsted acid-induced spiroketalization steps, was ultimately identified as the reliable strategy.1 aThorat, Sagar, S.1 aKrishna, Gamidi, Rama1 aKontham, Ravindar  uhttps://library.ncl.res.in/content/stereoselective-total-synthesis-pleurospiroketals-and-b01576nas a2200157   4500008004100000022001400041245012400055210006900179260000800248300001400256490000600270520096900276100002201245700002201267856012901289       2021                        eng d  a2052-412900aStrategies for the synthesis of furo-pyranones and their application in the total synthesis of related natural products0 aStrategies for the synthesis of furopyranones and their applicat  cMAY  a2110-21620 v83 a<p>The furo-pyranone framework is widely present in the molecular structure of various biologically potent natural products and un-natural small molecules, and it represents a valuable target in synthetic organic chemistry and medicinal chemistry. In the last five decades, numerous innovative synthetic methodologies have been disclosed for these bis-oxacyclic fused heterocycles, expanding the scope of accessible building blocks, efficient and affordable catalysis, facile reaction conditions, and overall practicality of the process. In this comprehensive review article, we focus on showcasing the complete spectrum (from the first report in the 1970s to the latest disclosure in 2020) of efforts devoted towards the synthesis of diverse classes of furo-pyranones through systematization and critical analysis of the accumulated experimental knowledge and their elegant applications in total syntheses of biologically interesting related natural products.</p>1 aThorat, Sagar, S.1 aKontham, Ravindar  uhttps://library.ncl.res.in/content/strategies-synthesis-furo-pyranones-and-their-application-total-synthesis-related-natural01462nas a2200205   4500008004100000022001400041245010200055210006900157260000800226300001400234490000700248520074800255100001701003700002201020700001601042700002601058700002201084700002101106856012901127       2022                        eng d  a0022-326300aReady access to benzannulated [5,5]-oxaspirolactones using Au(III)-catalyzed cascade cyclizations0 aReady access to benzannulated 55oxaspirolactones using AuIIIcata  cMAR  a3025-30410 v873 a<p>
	This work showcases an unprecedented Au(III)-catalyzed cascade cyclization of 2-(4-hydroxyalkynyl)benzoates to access benzannulated [5,5]-oxaspirolactones related to biologically active natural products. This reaction proceeds through an initial 5-endo-dig mode of hydroalkoxylation of the alkynol segment to give the oxocarbenium species (via cyclic enol-ether) followed by the addition of carboxylate onto the oxocarbenium that delivers the oxaspirolactone scaffold. While testing this method's scope, we found that the steric and electronic environment of the hydroxyl group could alter the reaction pathway that delivers isochromenone through a competitive 6-endo-dig mode of attack of the carboxylate onto the tethered alkyne.</p>
1 aMankad, Yash1 aThorat, Sagar, S.1 aDas, Pronay1 aKrishna, Gamidi, Rama1 aKontham, Ravindar1 aReddy, Srinivasa  uhttps://library.ncl.res.in/content/ready-access-benzannulated-55-oxaspirolactones-using-auiii-catalyzed-cascade-cyclizations01579nas a2200205   4500008004100000022001400041245014300055210007100198260000800269300001200277490000600289520081600295100002401111700002201135700001801157700002601175700001701201700002201218856013301240       2022                        eng d  a2052-412900aSilver-catalyzed [3 + 3]-annulation cascade of alkynyl alcohols and α,β-unsaturated ketones for the regioselective assembly of chromanes0 aSilvercatalyzed 3 3annulation cascade of alkynyl alcohols and αβ  cJAN  a802-8090 v93 aAn unprecedented Ag(i)-catalyzed [3 + 3]-annulation of alkynyl alcohols (5-hexyn-1-ols) and α,β-unsaturated ketones is reported to construct simple to complex chromanes. This transformation begins with hydroalkoxylation of alkynol through C–C triple bond activation to give cyclic-enol ether, followed by intermolecular 1,4-addition and intramolecular 1,2-addition of enol ethers onto the enone and oxidative aromatization or Grob-type elimination steps. Facile reaction conditions, broad substrate scope, good to excellent yields, and atom economy are the salient features of this protocol. Isolation of the active pyran-tethered cyclohexadiene reaction intermediate, additional supporting experiments, and DFT calculations strongly support the experimental findings and corroborate our proposed mechanism.1 aNakate, Ashwini, K.1 aThorat, Sagar, S.1 aJain, Shailja1 aKrishna, Gamidi, Rama1 aVanka, Kumar1 aKontham, Ravindar  uhttps://library.ncl.res.in/content/silver-catalyzed-3-3-annulation-cascade-alkynyl-alcohols-and-%CE%B1%CE%B2-unsaturated-ketones01591nas a2200229   4500008004100000022001400041245014200055210006900197260000800266300001600274490000700290520076700297653001701064653001601081653001501097100002201112700002201134700002501156700002601181700002201207856013201229       2023                        eng d  a0022-326300aRegioselective synthesis of benzannulated [5,6]-oxaspirolactones via Cu(II)-catalyzed cycloisomerization of 2-(5-Hydroxyalkynyl)benzoates0 aRegioselective synthesis of benzannulated 56oxaspirolactones via  cNOV  a16915-169330 v883 a<p>Spiroketals and oxaspirolactones are widely found in biologically active natural products, serving as important structural motifs. In this study, we present a Cu-(II)-catalyzed cascade cycloisomerization of 2-(5-hydroxyalkynyl)-benzoates, enabling the regioselective synthesis of benzannulated [5,6]-oxaspirolactones containing an isochromen-1-one moiety. This strategy offers a rapid and efficient approach to access a diverse array of benzannulated [5,6]-oxaspirolactones. The methodology presented here showcases a broad substrate scope, delivering good yields and scalability up to gram scale. The structures of the oxaspirolactones were unequivocally confirmed through single-crystal X-ray analysis and by analogy using H-1 and C-13-{H-1} NMR data.</p>
10aConstruction10aIsocumarins10aStrategies1 aThorat, Sagar, S.1 aShimpi, Sagar, P.1 aSambherao, Pooja, I.1 aKrishna, Gamidi, Rama1 aKontham, Ravindar  uhttps://library.ncl.res.in/content/regioselective-synthesis-benzannulated-56-oxaspirolactones-cuii-catalyzed-cycloisomerization01950nas a2200253   4500008004100000022001400041245009600055210006900151260000900220490000700229520108400236653004101320653002501361653001501386653003001401100002501431700002201456700002101478700001901499700001701518700002401535700002201559856011501581       2025                        eng d  a1861-472800aStudies on the stereoselective synthesis of sacubitril via a chiral amine transfer approach0 aStudies on the stereoselective synthesis of sacubitril via a chi  cMAR 0 v203 a<p>
	We present a comprehensive account of our efforts directed towards the synthesis of sacubitril, a neprilysin inhibitor used in combination with valsartan and marketed as Entresto (TM). Our initial approach to the formal synthesis of sacubitril employed a chiral pool strategy, utilizing (S)-pyroglutamic acid as a key building block and Cu(I)-mediated Csp2-Csp3 cross-coupling as a key transformation. Further investigations led to the development of chiral amine transfer (CAT) reagents-based stereoselective synthesis. This involved the E-selective construction of gamma-ylidene-butenolide from readily available biphenyl bromide and 4-pentynoic acid, the conversion of this butenolide to its ene-lactam using chiral amine, and substrate-controlled diastereoselective reduction of ene-lactam using Et3SiH or Pd/C, H2 (overall chiral amine transfer) as key transformations. Antipodal lactam intermediates were synthesized using corresponding chiral amines, and the stereochemical outcomes during the ene-lactam reduction with Et3SiH were rationalized by DFT studies.</p>
10aChiral Amine Transfer (CAT) approach10aChiral pool approach10aSacubitril10astereoselective synthesis1 aSadanande, Megha, V.1 aThorat, Sagar, S.1 aSharma, Himanshu1 aSingh, Geetika1 aVanka, Kumar1 aGonnade, Rajesh, G.1 aKontham, Ravindar  uhttps://library.ncl.res.in/content/studies-stereoselective-synthesis-sacubitril-chiral-amine-transfer-approach