00488nas a2200121   4500008004100000022001400041245005600055210005500111260007500166300001400241100002100255856009000276       2005                        eng d  a0936-521400aSodium methylsulfinylmethylide: a versatile reagent0 aSodium methylsulfinylmethylide a versatile reagent  aRUDIGERSTR 14, D-70469 STUTTGART, GERMANYbGEORG THIEME VERLAG KGcOCT  a2697-26981 aMondal, Mukulesh  uhttps://library.ncl.res.in/content/sodium-methylsulfinylmethylide-versatile-reagent-001496nas a2200169   4500008004100000022001400041245017400055210006900229260007100298300001400369490000700383520074000390100002101130700002601151700001901177856013001196       2006                        eng d  a0022-326300aFacile synthesis of 1,3,7-trihydroxyxanthone and its regioselective coupling reactions with prenal: simple and efficient access to osajaxanthone and nigrolineaxanthone F0 aFacile synthesis of 137trihydroxyxanthone and its regioselective  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJUN  a4992-49950 v713 a<p>A facile five-step synthesis of naturally occurring 1,3,7-trihydroxyxanthone has been described starting from 1,3,5-trimethoxybenzene via NBS-induced nuclear bromination, lithiation followed by an in situ benzoylation with methyl 2,5-dibenzyloxybenzoate, selective deprotection of the two benzyl groups, base-catalyzed intramolecular cyclization, and demethylations pathway with 62% overall yield. The regioselective coupling reactions of 1,3,7-trihydroxyxanthone with prenal in the presence of calcium hydroxide at room temperature and under thermal conditions at 140-150 degrees C have been demonstrated to exclusively obtain the natural products osajaxanthone in 75% yield and nigrolineaxanthone F in 98% yield, respectively.</p>1 aMondal, Mukulesh1 aPuranik, Vedavati, G.1 aArgade, N., P.  uhttps://library.ncl.res.in/content/facile-synthesis-137-trihydroxyxanthone-and-its-regioselective-coupling-reactions-prenal-001807nas a2200169   4500008004100000022001400041245019700055210006900252260007100321300001400392490000700406520103100413100002101444700002601465700001901491856012701510       2007                        eng d  a0022-326300aFacile phenol-driven intramolecular diastereoselective thermal/base-catalyzed dipolar [2+2] annulation reactions: an easy access to complex bioactive natural and unnatural benzopyran congeners0 aFacile phenoldriven intramolecular diastereoselective thermalbas  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAR  a2068-20760 v723 a<p>The complex bioactive natural and unnatural benzopyran congeners have been synthesized using one-/two-step approaches in very good yields from the reactions of two different dihydroxyphthalides, natural resorcyclic acid derivative, and trihydroxybenzophenone with citral and/or farnesal, via the phenol-driven intramolecular diastereoselective thermal/base-catalyzed dipolar [2 + 2] cycloaddition reactions and three different thermal intramolecular cyclization reactions. The effects of the nature and the position of phenolic groups in the starting materials on the course of these cycloaddition reactions have also been described. Depending upon the absence or presence of intramolecular hydrogen bonding of the phenolic group with the carbonyl moiety in the starting materials, these phenol-driven intramolecular thermal/base-catalyzed dipolar [2 + 2] cycloaddition reactions either furnished the kinetically controlled products or directly formed the thermodynamically controlled rearranged products, respectively.</p>1 aMondal, Mukulesh1 aPuranik, Vedavati, G.1 aArgade, N., P.  uhttps://library.ncl.res.in/content/facile-phenol-driven-intramolecular-diastereoselective-thermalbase-catalyzed-dipolar-22