<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Sanki, Aditya K.</style></author><author><style face="normal" font="default" size="100%">Bhattacharya, Rahul</style></author><author><style face="normal" font="default" size="100%">Atta, Ananta Kumar</style></author><author><style face="normal" font="default" size="100%">Suresh, Cheravakkattu G.</style></author><author><style face="normal" font="default" size="100%">Pathak, Tanmaya</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Diastereoselective addition of planar N-heterocycles to vinyl sulfone-modified carbohydrates: a new route to isonucleosides</style></title><secondary-title><style face="normal" font="default" size="100%">Tetrahedron</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2008</style></year><pub-dates><date><style  face="normal" font="default" size="100%">NOV</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">45</style></number><publisher><style face="normal" font="default" size="100%">PERGAMON-ELSEVIER SCIENCE LTD</style></publisher><pub-location><style face="normal" font="default" size="100%">THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND</style></pub-location><volume><style face="normal" font="default" size="100%">64</style></volume><pages><style face="normal" font="default" size="100%">10406-10416</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Michael-type addition reactions of planar N-heterocycles at the C-2 positions of vinyl sulfone-modified carbohydrates provide an efficient and general route for the carbon-N-heterocycle bond formation. Therefore, the addition pattern of planar heterocycles, such as imidazole, triazole, thymine, and adenine to 3-C-phenyisulfonyl-hex-2-enopyranosides (1 alpha/1 beta) and 3-C-p-toluenesulfonyl-pent-2-enofuranosides (2 alpha/2 beta) was studied for developing a general methodology for the synthesis of new classes of isonucleosides possessing a carbon-N-heterocycle linkage at C-2 positions of furanosyl and pyranosyl sugars. To a great extent, the anomeric configurations of the starting vinyl sulfones play crucial roles in deciding the diastereoselectivity of addition of heterocycles. However, the trityl protected 3-C-p-toluenesulfonyl-hex-2-enopyranosides (33 alpha/33 beta) were judged to be More practical starting materials for desulfortylation and deprotection for the synthesis of a new class of thymine and adenine deoxyisonucleosides. (C) 2008 Elsevier Ltd. All rights reserved.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">45</style></issue><work-type><style face="normal" font="default" size="100%">Article</style></work-type><custom3><style face="normal" font="default" size="100%">Foreign</style></custom3><custom4><style face="normal" font="default" size="100%">2.645</style></custom4></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Deshpande, Sachin G.</style></author><author><style face="normal" font="default" size="100%">Suresh, Cheravakkattu G.</style></author><author><style face="normal" font="default" size="100%">Pathak, Tanmaya</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Studies on the synthesis and unusual behavior of vinyl sulfone-modified hexenopyranosylthymines</style></title><secondary-title><style face="normal" font="default" size="100%">Carbohydrate Research</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">glycal</style></keyword><keyword><style  face="normal" font="default" size="100%">hexopyranosyl nucleosides</style></keyword><keyword><style  face="normal" font="default" size="100%">Michael addition</style></keyword><keyword><style  face="normal" font="default" size="100%">unsaturated nucleosides</style></keyword><keyword><style  face="normal" font="default" size="100%">vinyl sulfone-modified nucleosides</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year><pub-dates><date><style  face="normal" font="default" size="100%">MAY</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">7</style></number><publisher><style face="normal" font="default" size="100%">ELSEVIER SCI LTD</style></publisher><pub-location><style face="normal" font="default" size="100%">THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND</style></pub-location><volume><style face="normal" font="default" size="100%">343</style></volume><pages><style face="normal" font="default" size="100%">1163-1170</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Although vinyl sulfone-modified- (VSM) pent-2-enofuranosyl nucleosides 2 and hex-2-enopyranosyl glycoside 4 are easily synthesized from the corresponding mesylated sulfones le and 3c, respectively, via an oxidation-mesylation-elimination route, the 3'-C-sulfonyl-hex-2'-enopyranosylthymine 11 is not obtained from 10 and a glycal derivative 12 is formed instead. On the other hand, 3-C-sulfonyl-hex-3'-enopyranosylthymine 20 is easily synthesized from the mesylated sulfone 19. Again unlike the reaction patterns of VSM-pent-T-enofuranosyl nucleosides 2 and hex-2-enopyranosyl glycosides 4 as Michael acceptors, the reactions of nucleophiles with 3'-C-sulfonyl-hex-3'-enopyranosylthymine 20 yielded a rearranged product 21 instead of Michael adducts. (c) 2008 Published by Elsevier Ltd.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">7</style></issue><custom3><style face="normal" font="default" size="100%">Foreign</style></custom3><custom4><style face="normal" font="default" size="100%">1.898</style></custom4></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Das, Indrajit</style></author><author><style face="normal" font="default" size="100%">Suresh, Cheravakkattu G.</style></author><author><style face="normal" font="default" size="100%">Decout, Jean-Luc</style></author><author><style face="normal" font="default" size="100%">Pathak, Tanmaya</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Unusual addition of amines to C-2 of vinyl sulfone-modified-beta-D-pent-2-enofuranosyl carbohydrates: synthesis of a new class of beta-anomeric 2-amino-2,3-dideoxy-D-threo-pentofuranosides</style></title><secondary-title><style face="normal" font="default" size="100%">Carbohydrate Research</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">amino sugars</style></keyword><keyword><style  face="normal" font="default" size="100%">deoxyaminosugars</style></keyword><keyword><style  face="normal" font="default" size="100%">desulfonylation with Mg-MeOH-NiBr(2)</style></keyword><keyword><style  face="normal" font="default" size="100%">diastereoselective Michael addition</style></keyword><keyword><style  face="normal" font="default" size="100%">vinyl sulfone-modified carbohydrates</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year><pub-dates><date><style  face="normal" font="default" size="100%">JUN</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">8</style></number><publisher><style face="normal" font="default" size="100%">ELSEVIER SCI LTD</style></publisher><pub-location><style face="normal" font="default" size="100%">THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND</style></pub-location><volume><style face="normal" font="default" size="100%">343</style></volume><pages><style face="normal" font="default" size="100%">1287-1296</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;When 3-C-sulfonyl-pent-2-enofuranosides and 3-C-sulfonyl-hex-2-enofuranosides were reacted with primary and secondary amines, only the beta-anomeric methoxy group of the pent-2-enofuranoside did not cause any hindrance to incoming nitrogen nucleophiles. This resulted in the `unusual' addition of amines, in which the diastereoselectivity of the reaction was overwhelmingly in favor of amino sugars of the D-arabino configuration. Selected products were desulfonylated to obtain a new class of beta-anomeric 2-amino-2,3-dideoxy-D-threo-pentofuranosides. (C) 2008 Elsevier Ltd. All rights reserved.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">8</style></issue><work-type><style face="normal" font="default" size="100%">Article</style></work-type><custom3><style face="normal" font="default" size="100%">Foreign</style></custom3><custom4><style face="normal" font="default" size="100%">1.817</style></custom4></record></records></xml>