01382nas a2200301   4500008004100000022001400041245008300055210006900138260010600207300001400313490000700327520035600334653001100690653001900701653002400720100002400744700002500768700002000793700002000813700002300833700002300856700001200879700001800891700002100909700001900930700002200949856010900971       2005                        eng d  a0040-402000aUnusual stereochemical outcome of radical cyclization: synthesis of (+)-biotin0 aUnusual stereochemical outcome of radical cyclization synthesis   aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcSEP  a9273-92800 v613 a<p>An enantioselective synthesis of (+)-biotin 1 starting from naturally available cysteine is described. The key steps are the unusual stereochemical outcome of radical cyclization of compound 10 to prepare 5,5-fused system 11, and the introduction of C4-sidechain at C-6 in 13 via a Grignard reaction. (c) 2005 Elsevier Ltd. All rights reserved.</p>10abiotin10aexocyclization10aradical cyclization1 aChavan, Subhash, P.1 aChittiboyina, A., G.1 aRamakrishna, G.1 aTejwani, R., B.1 aRavindranathan, T.1 aKamat, Subhash, K.1 aRai, B.1 aSivadasan, L.1 aBalakrishnan, K.1 aRamalingam, S.1 aDeshpande, V., H.  uhttps://library.ncl.res.in/content/unusual-stereochemical-outcome-radical-cyclization-synthesis-biotin-001063nas a2200205   4500008004100000022001400041245011000055210006900165260007300234300001400307490000600321520025300327653002500580653002100605653002900626653003700655100001900692700001900711856012700730       2008                        eng d  a1566-736700aMulti-component carbon-carbon bond forming Mannich reaction catalyzed by yttria-zirconia based Lewis acid0 aMulticomponent carboncarbon bond forming Mannich reaction cataly  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAUG  a2445-24480 v93 a<p>A direct three component Mannich-type reaction of aldehyde, amine, and ketone (without silyl enolates) were efficiently catalyzed by yttria-zirconia based strong Lewis acid in aqueous acetonitrile. (C) 2008 Elsevier B.V. All rights reserved.</p>10abeta-amino carbonyls10aMannich reaction10amulti-component reaction10ayttria-zirconia based Lewis acid1 aRamalingam, S.1 aKumar, Pradeep  uhttps://library.ncl.res.in/content/multi-component-carbon-carbon-bond-forming-mannich-reaction-catalyzed-yttria-zirconia-001071nas a2200193   4500008004100000022001400041245017300055210006900228260005700297300001200354490000800366520023200374653002900606653002900635653004600664100001900710700001900729856012900748       2008                        eng d  a1011-372X00aSynthesis of alpha-amino phosphonates by three component condensation of carbonyl compound, amine, and dialkyl phosphite using Yttria-zirconia based Lewis acid catalyst0 aSynthesis of alphaamino phosphonates by three component condensa  a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcOCT  a315-3190 v1253 a<p>An efficient Yttria-zirconia Lewis acid catalyzed one-pot synthesis of alpha-amino phosphonates by three component coupling reaction of a carbonyl compound amine and dialkyl phosphates is described in good to high yield.</p>10aalpha-amino phosphonates10athree component coupling10aYttria-zirconia based Lewis acid catalyst1 aRamalingam, S.1 aKumar, Pradeep  uhttps://library.ncl.res.in/content/synthesis-alpha-amino-phosphonates-three-component-condensation-carbonyl-compound-amine-001071nas a2200193   4500008004100000022001400041245014100055210006900196260008600265300001800351490000700369520025000376653002300626653002200649653003700671100001900708700001900727856013100746       2009                        eng d  a0039-791100aYttria-zirconia-based lewis acid catalysis of the biginelli reaction: an efficient one-pot synthesis of 3,4-dihydropyrimidin-2-(1H)-ones0 aYttriazirconiabased lewis acid catalysis of the biginelli reacti  a325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USAbTAYLOR & FRANCIS INCcMAR  aPII 9092393990 v393 a<p>Yttria-zirconia-based Lewis acid efficiently catalyzes the three-component cyclocondensation reaction of aldehyde, -keto ester, and urea or thiourea in refluxing acetonitrile to produce the corresponding dihydropyrimidones in high yields.</p>10aBiginelli reaction10adihydropyrimidone10ayttria-zirconia-based Lewis acid1 aRamalingam, S.1 aKumar, Pradeep  uhttps://library.ncl.res.in/content/yttria-zirconia-based-lewis-acid-catalysis-biginelli-reaction-efficient-one-pot-synthesis-001464nas a2200217   4500008004100000022001400041245011000055210006900165260011700234300001200351520058300363653001600946653002200962653002600984653002801010100001901038700002701057700001901084700001901103856012401122       2013                        eng d  a1551-700400aConcise synthesis of (5R,6S)-tert-butyl 5-acetoxy-6-(hydroxymethyl)-5,6-dihydropyridine-1(2H)-carboxylate0 aConcise synthesis of 5R6Stertbutyl 5acetoxy6hydroxymethyl56dihyd  aC/O ALAN R KATRITZKY, UNIV FLORIDA, DEPT CHEMISTRY, PO BOX 117200, GAINESVILLE, FL 32611 USAbARKAT USA INCcOCT  a220-2273 a<p>An efficient synthesis of (5R,6S)-tert-butyl 5-acetoxy-6-(hydroxymethyl)-5,6-dihydropyridine-1(2H)-carboxylate 1, a common intermediate for various polyhydroxylated piperidines is reported in six steps with 32% overall yield starting from Garner's aldehyde. The key steps include the diastereoselective nucleophilic addition and intramolecular cyclization. (5R,6S)-tert-butyl 5-acetoxy-6-(hydroxymethyl)-5,6-dihydropyridine-1(2H)-carboxylate is a common precursor for the synthesis of 1-deoxy-L-mannojirimycin, 1-deoxy-L-idonojirimycin, L-fagomycin and related analogues.</p>10acyclization10aGarner's aldehyde10anucleophilic addition10apolyhydroxy piperidines1 aRamalingam, S.1 aBhise, Ankushkumar, D.1 aShow, Krishanu1 aKumar, Pradeep  uhttps://library.ncl.res.in/content/concise-synthesis-5r6s-tert-butyl-5-acetoxy-6-hydroxymethyl-56-dihydropyridine-12h-0