- Exploring the Biochemical Foundations of a Successful GLUT1-Targeting Strategy to BNCT: Chemical Synthesis and in Vitro Evaluation of the Entire Positional Isomer Library of ortho-Carboranylmethyl-Bearing Glucoconjugates
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Boron neutron capture therapy (BNCT) is a noninvasive binary therapeutic modality applicable to the treatment of cancers. While BNCT offers a tumor-targeting selectivity that is difficult to match by other means, the last obstacles preventing the full har
- Matovi?, Jelena,J?rvinen, Juulia,Sokka, Iris K.,Imlimthan, Surachet,Raitanen, Jan-Erik,Montaser, Ahmed,Maaheimo, Hannu,Huttunen, Kristiina M.,Per?niemi, Sirpa,Airaksinen, Anu J.,Sarparanta, Mirkka,Johansson, Mikael P.,Rautio, Jarkko,Ekholm, Filip S.
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p. 285 - 304
(2020/12/21)
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- The First Total Syntheses of Enantiomerically Pure Naturally Occuring Ellagitannins Gemin D and its Regioisomer Hippomanin A
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The total syntheses of naturally occuring ellagitannins gemin D (1) and its regioisomer hippomanin A (2) are reported. In addition, the phase-transfer catalyzed benzylation reaction of the 2,3-glucopyranoside diols 3-7 is described. Our studies have illustrated the influence of the structure of 2,3-glucopyranoside diols on the regioselectivity of the phase-transfer catalyzed benzylation at their free 2,3-OH groups. We could show, that both phase-transfer catalyzed benzylations of 2,3-glucopyranoside diols using tetrabutylammonium hydrogensulfate (Bu4NHSO4) or using tetrabutylammonium iodide (Bu4NI) disfavour the formation of the corresponding 3-O-monobenzylated products and preferentially give the 2-O-monobenzylated products. However, the ratio of the generated 2- versus 3-O-mono- and 2,3-dibenzylated products from these reactions also strongly depends upon the nature of the starting materials. The glucopyranosides 3 and 4 are the first examples, which allow the completely regioselective monobenzylation at the 2-OH positions by a phase-transfer catalyzed reaction.
- Khanbabaee, Karamali,Loetzerich, Kerstin,Borges, Markus,Grosser, Mathias
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p. 159 - 166
(2007/10/03)
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- The structures and reactions of stannylene acetals from carbohydrate-derived trans-diols. Part I. In the absence of added nucleophiles
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Di-n-butylstannylene acetals of benzyl 4,6-O-benzylidene-α- and -β-D-glucopyranoside and galactopyranoside have been prepared and studied in solution by 1H, 13C, and 119Sn nuclear magnetic resonance spectroscopy.The species present in solution have been identified from the 119Sn nmr spectral data, by comparison of the 13C nmr chemical shifts of the stannylene acetals and their precursor diols and also by analysis of the products of reactions performed without added nucleophiles.The orientations of the two substituents on the carbons in the pyranose ring attached to the carbons in the stannylene ring determine the structures adopted by the stannylene acetal in solution.If one substituent is axial and the other equatorial, the stannylene acetal exists as a single symmetrical dimer in which the two oxygen atoms in the two 1,3,2-dioxastannolane rings adjacent to the axial substituents are dicoordinate.A stannylene acetal with two adjacent equatorial substituents exists as a non-interconverting mixture of dimers; one with two adjacent axial substituents is present as a rapidly interconverting mixture of dimers, trimers, and tetramers.Benzoylation and benzylation of the latter two types of stannylene acetals have been performed and have been shown to be only slightly regioselective in contrast to the known highly regioselective reactions of the first type.Only when single dimers are present are regiospecific or highly regioselective reactions obtained.The causes of the variation in the species present and of the reaction regioselectivity for different stannylene acetals are discussed.
- Grindley, T. Bruce,Thangarasa, Rasiah
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p. 1007 - 1019
(2007/10/02)
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- CHEMO-, STEREO- AND REGIOSELECTIVE HYDROGENOLYSIS OF CARBOHYDRATE BENZYLIDENE ACETALS. SYNTHESIS OF BENZYL ETHERS OF BENZYL α-D-, METHYL β-D-MANNOPYRANOSIDES AND BENZYL α-D-RHAMNOPYRANOSIDE BY RING CLEAVAGE OF BENZYLIDENE DERIVATIVES WITH THE LiAlH4-AlCl3
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Treatment of benzyl α-(1) and methyl β-D-mannopyranoside (2) with α,α-dimethoxytoluene gave the exo and endo isomers (3,5 and 4,6) of the dibenzylidene derivatives of 1 and 2.Hydrogenolysis of the exo isomers (3 and 5) with a molar equivalent of AlH2Cl ga
- Liptak, Andras,Imre, Janos,Harangi, Janos,Nanasi, Pal,Neszmelyi, Andras
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p. 3721 - 3728
(2007/10/02)
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