01238nas a2200157   4500008004100000022001400041245011800055210006900173260010600242300001400348490000700362520053200369100002700901700002000928856013200948       2007                        eng d  a0040-403900aPropargyl 1,2-orthoesters as glycosyl donors: stereoselective synthesis of 1,2-trans glycosides and disaccharides0 aPropargyl 12orthoesters as glycosyl donors stereoselective synth  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcSEP  a6564-65680 v483 a<p>Propargyl 1,2-orthoesters are identified as glycosyl donors. Various glycosides and disaccharides were synthesized in a stereoselective manner using AuBr3 as the promoter. AuBr3 may activate the alkyne resulting in the formation of a 1,2-dioxolenium ion and also behaves as a Lewis acid to facilitate the attack of the glycosyl acceptor. The versatility of the protocol was demonstrated using a panel of aglycones comprising aliphatic, alicyclic, steroidal and sugar alcohols. (C) 2007 Elsevier Ltd. All rights reserved.</p>1 aSureshkumar, Gopalsamy1 aHotha, Srinivas  uhttps://library.ncl.res.in/content/propargyl-12-orthoesters-glycosyl-donors-stereoselective-synthesis-12-trans-glycosides-and-001092nas a2200145   4500008004100000022001400041245014300055210006900198260011000267300001400377520038300391100002700774700002000801856012500821       2008                        eng d  a1359-734500aGold mediated glycosylations: selective activation of propargyl 1,2-orthoesters in the presence of aglycones containing a propargyl moiety0 aGold mediated glycosylations selective activation of propargyl 1  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcJUL  a4282-42843 a<p>Selective activation of propargyl 1,2-orthoesters in the presence of propargyl glycosides and propargyl ethers was studied; a catalytic amount of AuBr(3) activated the propargyloxy, group of the 1,2-orthoester thereby giving access to disaccharides with the propargyl group at the reducing end; furthermore, propargyl ethers were unaffected under the reaction conditions.</p>1 aSureshkumar, Gopalsamy1 aHotha, Srinivas  uhttps://library.ncl.res.in/content/gold-mediated-glycosylations-selective-activation-propargyl-12-orthoesters-presence-001956nas a2200205   4500008004100000022001400041245009600055210006900151260008800220300001200308490000700320520116600327100002201493700001801515700002001533700002701553700002001580700002901600856012101629       2011                        eng d  a1044-549800aEnhanced DNA binding of 9-omega-amino alkyl ether analogs from the plant alkaloid berberine0 aEnhanced DNA binding of 9omegaamino alkyl ether analogs from the  a140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USAbMARY ANN LIEBERT, INCcFEB  a123-1330 v303 a<p>To understand the structure-activity relationship of isoquinoline alkaloids, absorption, fluorescence, circular dichroism, and thermodynamics were employed to study the interaction of five C-9-omega-amino alkyl ether analogs from the plant alkaloid berberine with double-stranded calf thymus DNA. The C-9 derivatization resulted in dramatic enhancements in the fluorescence emission of these compounds. The most remarkable changes in the spectral and binding properties were in the BC4 and BC5 derivatives. Interactions of these analogs, which have an additional recognition motif with DNA, were evaluated through different spectroscopic and calorimetric titration experiments. The analogs remarkably enhanced the DNA binding affinity and the same was directly dependent on the alkyl chain length. The analog with six alkyl chains enhanced the DNA binding affinity by about 33 times compared with berberine. The binding became more entropically driven with increasing chain length. These results may be of potential use in the design of berberine derivatives and understanding of the structure-activity relationship for improved therapeutic applications.</p>1 aIslam, Md, Maidul1 aBasu, Anirban1 aHossain, Maidul1 aSureshkumar, Gopalsamy1 aHotha, Srinivas1 aKumar, Gopinatha, Suresh  uhttps://library.ncl.res.in/content/enhanced-dna-binding-9-omega-amino-alkyl-ether-analogs-plant-alkaloid-berberine-001469nas a2200193   4500008004100000022001400041245012800055210006900183260011000252300001400362490000600376520065800382100002201040700002701062700001901089700002201108700002001130856012501150       2011                        eng d  a1477-052000aFacile synthesis of unusual glycosyl carbamates and amino acid glycosides from propargyl 1,2-orthoesters as glycosyl donors0 aFacile synthesis of unusual glycosyl carbamates and amino acid g  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcMAR  a5951-59590 v93 a<p>Propargyl 1,2-O-orthoesters are exploited for the synthesis of 1,2-trans O-glycosides of protected amino acids. N-Fmoc- and N-Cbz protected serine/threonine - benzyl/methyl esters reacted well with glucosyl-, galactosyl-, mannosyl- and lactosyl- derived propargyl 1,2-orthoesters affording respective 1,2-trans glycosides in good yields under AuBr(3)/4 angstrom MS Powder/CH(2)Cl(2)/rt. t-Boc serine derivative gave serine 1,2-orthoester and glycosyl carbamate. Optimized conditions enabled preparation of new glycosyl carbamates from N-Boc protected amines in a single step using gold catalysts and propargyl 1,2-orthoesters in excellent yields.</p>1 aShaikh, Ashif, Y.1 aSureshkumar, Gopalsamy1 aPati, Debasish1 aGupta, Sayam, Sen1 aHotha, Srinivas  uhttps://library.ncl.res.in/content/facile-synthesis-unusual-glycosyl-carbamates-and-amino-acid-glycosides-propargyl-12-0