نتایج جستجو برای: 1,2-O-isopropylidene derivatives of aldohexoses

تعداد نتایج: 21483696  

Journal: :Carbohydrate research 2001
I I Cubero M T López-Espinosa R R Díaz F F Montalbán

Either 3-O-benzoyl- (2a) or 3-O-benzyl-1,2-O-isopropylidene-beta-D-fructopyranose (2b) were regioselectively O-benzylated at C-4 to give 4a and 4b, respectively, which were transformed into 5-azido-3-O-benzoyl-4-O-benzyl- (6a) and 5-azido-3,4-di-O-benzyl-5-deoxy-1,2-O-isopropylidene-alpha-L-sorbopyranose (6b) by nucleophilic displacement of the corresponding 5-O-mesyl derivatives 5a and 5b by s...

Journal: :Carbohydrate research 2009
Giorgio Catelani Felicia D'Andrea Lorenzo Guazzelli Venerando Pistarà

The transformation of (5R)-2,6-di-O-benzyl-5-C-methoxy-beta-D-galactopyranosyl-(1-->4)-2,3:5,6-di-O-isopropylidene-aldehydo-D-glucose dimethyl acetal (8) into partially protected derivatives of D-xylo- and L-lyxo-aldohexos-5-ulose has been reported, applying appropriate epimerisation methods to its 3'-O- and 4'-O-protected alcoholic derivatives.

Retention behavior of molecules mostly depends on their chemical structure. Retention data of biologically active molecules could be an indirect relationship between their structure and biological or pharmacological activity, since the molecular structure affects their behavior in all pharmacokinetic stages. In the present paper, retention parameters (RM0) of biologically active 1,2-O-isopropyl...

Retention behavior of molecules mostly depends on their chemical structure. Retention data of biologically active molecules could be an indirect relationship between their structure and biological or pharmacological activity, since the molecular structure affects their behavior in all pharmacokinetic stages. In the present paper, retention parameters (RM0) of biologically active 1,2-O-isopropyl...

2015
Madhuri Vangala Ganesh P Shinde

The TMSOTf-mediated synthesis of β-configured spirocyclic 2-substituted-2-oxazoline ribosides was achieved using a "Ritter-like" reaction in toluene through nucleophilic addition of electron-rich nitriles to the oxacarbenium ion intermediate of 1,2;3,4-di-O-isopropylidene-β-D-psicofuranose derivatives with concomitant intramolecular trapping of the C2 hydroxymethyl group on the electrophilic ni...

2017
Neha Rana Manish Kumar Vinod Khatri Jyotirmoy Maity Ashok K Prasad

Conversion of D-glucose to 4-C-hydroxymethyl-1,2-O-isopropylidene-α-D-ribofuranose, which is a key precursor for the synthesis of different types of bicyclic/spiro nucleosides, led to the formation of an inseparable 1:1 mixture of the desired product and 4-C-hydroxymethyl-1,2-O-isopropylidene-α-D-xylofuranose. A convenient environment friendly Novozyme®-435 catalyzed selective acetylation metho...

Journal: :Carbohydrate research 2007
Jianjun Zhang Shiqiang Yan Xiaomei Liang Jingping Wu Daoquan Wang Fanzuo Kong

1-O-Allyloxycarbonyl (or ethyloxycarbonyl)-2-azido-2-deoxy-3-O-benzyl (or allyl, or benzoyl)-4,6-O-isopropylidene-beta-d-mannopyranose derivatives were prepared from the corresponding 2-hydroxy-beta-d-glucopyranosyl carbonates in high yields via triflation of the 2-hydroxyl group and subsequent SN2 displacement with azide ion. An N-acetyl-mannosamine-containing trisaccharide, a fragment of the ...

Journal: :Carbohydrate research 2004
Vladimír Církva Radek Polák Oldrich Paleta Karel Kefurt Jitka Moravcová Milan Kodícek Stanislav Forman

6-O-(4,4,5,5,6,6,7,7,7-Nonafluoro-2-hydroxyheptyl)-, 6-O-(4,4,5,5,6,6,7,7,8,8,9,9,9-tridecafluoro-2-hydroxynonyl)-, and 6-O-(4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-heptadecafluoro-2-hydroxyundecyl)-d-galactopyranose (9, 10, and 11, resp.) were prepared by a two-step synthesis including the reaction of 1,2:3,4-di-O-isopropylidene-alpha-d-galactopyranose with 2-[(perfluoroalkyl)methyl]oxiranes un...

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