Search Results

You are looking at 1 - 10 of 89 items :

Clear All

The 27 th International Carbohydrate Symposium (ICS-27), the bi-annual symposium of the International Carbohydrate Organization (ICO), an associate organization of IUPAC, was held at the Indian Institute of Science, Bangalore, India, 12–17 January 2014. Conducting this symposium was a historic moment and an acknowledgment of the country that has made great strides in the science and technology of carbohydrates over the last couple of decades and before. The symposium was attended by ~700 delegates from over 40 countries, well represented in terms of

Abstract

Conformational analysis of unnatural seven-membered sugars, namely, septanoses and septanosides are discussed herein. The conformational properties of these sugars in the solid state, solution phase and computational methods are presented. The analyses reveal that conformations of septanosides are diverse and largely unpredictable, as compared furanosides and pyranosides.

Abstract

Cyclodextrins (CDs) – a family of cyclic oligosaccharides – are ideal building blocks for the construction of environmentally benign materials. Herein, we reflect upon the serendipitous discovery of two classes of extended crystalline materials – referred to as cyclodextrin metal-organic frameworks (CD-MOFs) and CD-Bamboo – based on CDs which offer opportunities for potential applications in the world of industry and commerce all the way from sequestering carbon dioxide to extracting gold in an eco-friendly manner. The crucial role of serendipity in scientific research expresses itself two times over at the boundaries between coordination chemistry with materials science.

Abstract

Addition of a carbene to a glycal is the prominent method for the synthesis of 1,2-cyclopropyl carbohydrates. This incorporation of a cyclopropane into a carbohydrate scaffold enables divergent reactivity, with the two main classes being ring expansion and cleavage to 2-C-branched carbohydrates. A wide variety of products are obtained depending on the functionality attached to the cyclopropane (none or ester or halogens) and the promoter (Lewis acid, Brønsted acid, halophile or base) used in the reaction. This article reviews progress in the synthesis and reactions of 1,2-cyclopropyl carbohydrates since 2000 and discloses efforts by our group in the area.

Abstract

Anionic fucose-containing polysaccharides (fucoidans of brown seaweeds, sulfated fucans and fucosylated chondroitin sulfates of invertebrates) are attracting a rapidly growing research interest due to different types of their biological activity discovered in recent years. In particular, algal fucoidans are characterized by large structural variations depending on the species used for their isolation and by the lack of structural regularity due to random distribution of both carbohydrate and non-carbohydrate substituents along the polymer chains. These features make it difficult to find distinct correlations between structural elements and biological properties of polysaccharides. Nevertheless, there is expectation that systematic structural and biochemical studies of fucoidans will form a basis for the development of new drugs. Herewith we summarize our recent results on the influence of fucoidan structure on blood coagulation.

Abstract

Structural studies in this laboratory encompass four of the five major classes of plant lectins, including the one discovered by us. In addition to addressing issues specific to individual lectins, the work provided insights into protein folding, quaternary association and generation of ligand specificity. Legume and β-prism fold lectins constitute families of proteins in which small alterations in essentially the same tertiary structure lead to large variations in quaternary structure, including that involving an open structure. Strategies for generating ligand specificity include water bridges, variation in loop length, post translational modification and oligomerization. Three of the structural classes investigated have subunits with three-fold symmetry. The symmetry in the structure is reflected in the sequence to different extents in different sub-classes. The evolutionary implications of this observation have been explored. The work on lectins has now been extended to those from mycobacteria.

Abstract

Pyranosidic allylic (Ferrier) cations that share dicobalt hexacarbonyl propargyl (Nicholas) stabilization at C-1, can be easily generated by treatment of hexacarbonyldicobalt alkynyl glycals with BF3·OEt2, and display a remarkable reactivity leading to a variety of products. The substituent at O-6 in these glycals plays a pivotal role in directing the outcome of the transformations. Accordingly, 6-O-benzyl or 6-O-allyl groups cause a series of transformations resulting in the stereoselective formation of oxepanes through a process that involves an initial hydride transfer step from the allyl or benzyl substituent to the Ferrier–Nicholas cation. On the contrary, 6-OH derivatives undergo an overall ring contraction to branched tetrahydrofuran derivatives. 6-O-Silyl derivatives, in the presence of heteroaryl nucleophiles, were transformed into C-3 branched bis-C-C-glycosides, containing two of such molecules.

27th International Carbohydrate Symposium (ICS27)January 12–17, 2014, Bangalore, India http://www.ics27bangalore.in/ 247th ACS National Meeting & ExpositionMarch 16–20, 2014, Dallas, TX, USA Program Theme: Chemistry of Energy/Advanced Materials for New Opportunities http://www.divched.org/content/247th-acs-national-meetingexposition 5th Nordic Wood Biorefinery Conference (NWBC 2014)March 25–27, 2014, Stockholm, Sweden Topics: Biorefinery systems and processes; Biorefinery products: chemicals, materials and fuels Information: http://www.innventia.com/nwbc2014 13

27th International Carbohydrate Symposium (ICS27)January 12–17, 2014, Bangalore, India http://www.ics27bangalore.in/ 247th ACS National Meeting & ExpositionMarch 16–20, 2014, Dallas, TX, USA Program Theme: Chemistry of Energy/Advanced Materials for New Opportunities http://www.divched.org/content/247th-acs-national-meetingexposition 5th Nordic Wood Biorefinery Conference (NWBC 2014)March 25–27, 2014, Stockholm, Sweden Topics: Biorefinery systems and processes; Biorefinery products: chemicals, materials and fuels Information: http://www.innventia.com/nwbc2014 13

The 9th International Conference “Wood Science and Engineering in the third Millenium” (ICWSE 2013) November 7–9, 2013, Transilvania University, Brasov, Romania Tel/Fax : +40 268 419 581; http://www2.unitbv.ro 27th International Carbohydrate Symposium (ICS27) January 12–17, 2014, Bangalore, India http://www.ics27bangalore.in/ 247th ACS National Meeting & Exposition March 16–20, 2014, Dallas, TX, USA Program Theme: Chemistry of Energy/Advanced Materials for New Opportunities http://www.divched.org/content/247th-acs-national-meetingexposition 5th Nordic Wood