Generation of α-Linked Oligosaccharide Libraries by Random Glycosylation on Unprotected Acceptors Yili Ding 1* , Chamakura VNS Varaprasad 2 , Saeed El-Ashram 1 , Jiedan Liao 1 , Nan Zhang 1 , Shujian Huang 1 and Bingyun Wang 1 1 Life Science Department, Foshan University, Foshan, Guangdong, China 2 Das Pharma, Turangi, Kakinada, Andhra Pradesh, India *Corresponding author: Ding Y, Life Science Department, Foshan University, Foshan, Guangdong, China, Tel: +13052299170; E-mail: yiding93@yahoo.com Received date: February 07, 2018; Accepted date: February 21, 2018; Published date: February 25, 2018 Copyright: © 2018 Ding Y, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract Background Te GlcNAc related disaccharides were reported to show inhibitory activity on breast tumor cells (MDA- MB-231). However, synthesis of disaccharides is lengthy, laborious and time consuming, and it is necessary to fnd more efcient methods to generate the disaccharide libraries. Random glycosylation has been an established practice to generate β-linked disaccharides library. Synthesis of α-linked disaccharide libraries by random glycosylation hasn’t been explored yet. We present our results on the synthesis of α-linked GlcNAc related disaccharide libraries by random glycosylation in this article. Results Employing random glycosylation as a key step on an unprotected GlcNAc monosaccharide, and afer deprotection and careful purifcation, few α-linked GlcNAc related disaccharide libraries were obtained in acceptable ratios, and the results were confrmed by mass and NMR spectral data. Conclusion Random glycosylation was demonstrated as an efcient method for the synthesis of α-linked GlcNAc related oligosaccharide libraries. Keywords: Oligosaccharide; Random glycosylation; Combinatorial chemistry; α-Linked GlcNAc oligosaccharide library Introduction Interaction between cell surface carbohydrate ligands and various protein receptors forms the basis of recognition events, which are fundamental to vastly diverse range of biological and pathological processes [1]. Cell surface carbohydrates constitute efcient receptors for hormones, toxins, bacteria and viruses [2]. Terefore, synthetic oligosaccharides can be screened as cell adhesion inhibitors or antigens from which specifc antibodies can be triggered. However, oligosaccharides are very complex and diverse, and their synthesis is both lengthy and expensive [3]. Recent research showed that the most important residue in the structures of oligosaccharide epitopes recognized by the antibodies are the terminal fragments which normally are disaccharides, trisaccharides or tetrasaccharides [4]. Tis fact elicited lot of interest to synthesize a diverse array of small size (di, tri and tetra) oligosaccharide libraries for studying their biological properties instead of synthesizing the whole size oligosaccharides. Specifc disaccharides have been identifed as markers for certain types of tumors. For example, the chondroitin sulfate disaccharides were reported to show inhibitory activity on breast tumor cells (MDA- MB-231) [5], 16 chondroitin sulfate disaccharides were tested on the more aggressive MDA-MB-231 cell line, a statistically signifcant decrease in cell viability was observed for some of disaccharides at 100 μg/mL concentration, and the results indicated that both the number and position of the sulfate groups present in the chondroitin sulfate disaccharide have an efect on MDA-MB-231 cell viability. Tese results stimulated lot of interest among chemists to fnd the more efcient methods to synthesize the small sulfated oligosaccharide libraries. Accordingly, using an orthogonal protection strategy, sulfated Gal- β1,3/4-GlcNAc disaccharide library was reported by Tu et al. [6], while synthesis of 48 disaccharide building blocks for assembling of a heparin oligosaccharide library was achieved by Hung research group [7]. Further, from a common intermediate possessing orthogonally removable protective groups, all 16 disaccharide sulfates were systematically synthesized by Suda et al. [8]. Tese syntheses are both lengthy and time consuming, and there is a large scope to fnd more efcient methods for generating the oligosaccharide libraries. Random glycosylation on unprotected glycosylation acceptors can generate oligosaccharide libraries containing all possible oligosaccharides with certain confguration [9]. Random galactosylation on an unprotected GlcNAc acceptor generated all six- possible disaccharide library with α and β linkages, and six disaccharides were chemically synthesized to compare with the library in HPLC to confrm the results [10]. Te ratio of six disaccharides is not good enough for their biological activity evaluation, even many O r g a n i c C h e m i s t r y : C u r r e n t R e s e a r c h ISSN: 2161-0401 Organic Chemistry: Current Research Ding et al., Organic Chem Curr Res 2018, 7:1 DOI: 10.4172/2161-0401.1000188 Research Article Open Access Organic Chem Curr Res, an open access journal ISSN: 2161-0401 Volume 7 • Issue 1 • 1000188