01956nas a2200253 4500008004100000022001400041245007900055210006900134260007400203300001200277490000700289520102700296653001801323653003701341653002301378653004501401100002401446700002501470700002801495700002501523700002201548700002201570856011001592 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

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.

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. uhttp://library.ncl.res.in/content/synthesis-and-characterization-superhydrophobic-superoleophilic-surface01434nas a2200181 4500008004100000245008000041210006900121260000800190300001200198490000700210520081100217100002401028700001601052700002401068700002801092700002201120856011001142 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. uhttp://library.ncl.res.in/content/biocompatible-superhydrophobic-coating-material-biomedical-applications01104nas a2200181 4500008004100000245013000041210006900171260000800240300001400248490000700262520040700269100002600676700002200702700002800724700002400752700002200776856012400798 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 uhttp://library.ncl.res.in/content/lewis-acid-catalyzed-cascade-annulation-alkynols-alpha-ketoesters-facile-access-gamma01168nas a2200169 4500008004100000022001400041245006100055210005600116260000800172300001400180490000600194520064500200100002200845700002300867700002200890856008600912 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

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.

1 aThorat, Sagar, S.1 aPalange, Megha, N.1 aKontham, Ravindar uhttp://library.ncl.res.in/content/four-step-total-synthesis-yaoshanenolides-and-b01153nas a2200169 4500008004100000022001400041245013300055210006900188260000900257300001200266490000700278520050200285100002200787700002200809700002200831856013000853 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

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.

1 aThorat, Sagar, S.1 aKataria, Priyanka1 aKontham, Ravindar uhttp://library.ncl.res.in/content/synthesis-furo23-bpyran-2-ones-through-agi-or-agi-aui-catalyzed-cascade-annulation-alkynols01326nas a2200169 4500008004100000022001400041245007100055210006500126260000900191300001600200490000700216520076900223100002200992700002601014700002201040856009401062 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 uhttp://library.ncl.res.in/content/stereoselective-total-synthesis-pleurospiroketals-and-b01575nas a2200157 4500008004100000022001400041245012400055210006900179260000800248300001400256490000600270520096900276100002201245700002201267856012801289 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

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.

1 aThorat, Sagar, S.1 aKontham, Ravindar uhttp://library.ncl.res.in/content/strategies-synthesis-furo-pyranones-and-their-application-total-synthesis-related-natural01461nas a2200205 4500008004100000022001400041245010200055210006900157260000800226300001400234490000700248520074800255100001701003700002201020700001601042700002601058700002201084700002101106856012801127 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

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.

1 aMankad, Yash1 aThorat, Sagar, S.1 aDas, Pronay1 aKrishna, Gamidi, Rama1 aKontham, Ravindar1 aReddy, Srinivasa uhttp://library.ncl.res.in/content/ready-access-benzannulated-55-oxaspirolactones-using-auiii-catalyzed-cascade-cyclizations01578nas a2200205 4500008004100000022001400041245014300055210007100198260000800269300001200277490000600289520081600295100002401111700002201135700001801157700002601175700001701201700002201218856013201240 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 uhttp://library.ncl.res.in/content/silver-catalyzed-3-3-annulation-cascade-alkynyl-alcohols-and-%CE%B1%CE%B2-unsaturated-ketones