128376-91-0

Tea aroma precursor glycosides are plant-derived natural products with great economic value. However, the preparation of these glycosides remains largely overlooked in the past decades. Herein, we report a mild, efficient, and sustainable chemocatalytic procedure for the production of tea aroma precursor glycosides. During the study of the glycosidation, the catalysts were found to be decisive in the product formation favoring different reaction pathways; in addition, the influence of molecular sieves was elucidated. With regard to these findings, the serious problem of the competing orthoester formation side reaction was successfully overcome with low catalyst loading (1 mol %) and the use of 5 ? molecular sieves, leading to the preparation of a variety of tea aroma precursor β-d-glucopyranosides and β-primeverosides on a gram scale in high yields in an economical way. Taken together, the current approach features catalytic glycosidation with non-toxic and low-cost catalysts, demonstrates highly favorable greenness and sustainability, and promises industrial production of tea aroma precursor glycosides.

Due to their pronounced bioactivity and limited availability from natural resources, metabolites of the soft coral Pseudopterogorgia elisabethae, such as erogorgiaene and the pseudopterosines, represent important target molecules for chemical synthesis. We have now developed a particularly short and efficient route towards these marine diterpenes exploiting an operationally convenient enantioselective cobalt-catalyzed hydrovinylation as the chirogenic step. Other noteworthy C?C bond forming transformations include diastereoselective Lewis acid-mediated cyclizations, a Suzuki coupling and a carbonyl ene reaction. Starting from 4-methyl-styrene the anti-tubercular agent (+)-erogorgiaene (>98 % ee) was prepared in only 7 steps with 46 % overall yield. In addition, the synthesis of the pseudopterosin A aglycone was achieved in 12 steps with 30 % overall yield and, surprisingly, was found to exhibit a similar anti-inflammatory activity (inhibition of LPS-induced NF-κB activation) as a natural mixture of pseudopterosins A?D or iso-pseudopterosin A, prepared by β-D-xylosylation of the synthetic aglycone.

The invention relates to a tea leaf perfumery precursor glucoside and a synthesizing method thereof. The synthesizing method comprises the following steps of synthesizing ten glucosides including aromatic alcohol ( alkanol )-beta -D-glucosides and aromatic alcohol (alkanol )-beta -D-primrose indicans. The synthesizing method disclosed by the invention is a glucoside synthesizing method which is good in selectivity, high in production rate and low in cost.

Pseudaminic acid (Pse) is a nonulosonic acid unique to bacterial species, found as a component of important cell surface glycans and glycoproteins in various pathogenic species, such as the critical hospital threat Pseudomonas aeruginosa. Herein we present the development of a facile and scalable de novo synthesis of Pse and its functionalized derivatives from easily available Cbz-l-allo-threonine methyl ester (16 steps in 11% yield). The key reactions in our de novo synthesis involve the diastereoselective glycine thioester isonitrile-based aldol-type reaction to create the 1,3-anti-diamino skeleton, followed by the Fukuyama reduction and the indium-mediated Barbier-type allylation. Moreover, we have studied the glycosylation of the Pse glycosyl donors and identified the structural determinants for its glycosylation diastereoselectivity, which enabled us to complete the total synthesis of P. aeruginosa 1244 pilin trisaccharide α-5NβOHC47NFmPse-(2→4)-β-Xyl-(1→3)-FucNAc.

Eleven shikonin glycosides were synthesized and evaluated for their antitumor activity in vitro. Some of them were found to exhibit cytotoxic activities against both drug sensitive cell lines (K562, MCF-7 and HL60) and their drug resistant cell sublines (K562/ADR, MCF-7/ADR and HL60/ADR).

(Matrix Presented) The synthesis of a novel class of aminoglycosides, pyranmycins, is reported along with the structure activity relationship (SAR) of their antibacterial activity against Escherichia coli. Two pyranmycins show prominent activity (9 μM). P

The mollu-series glycosphingolipids, O-α-D-mannopyranosyl-(1->3)-O-β-D-mannopyranosyl-(1->4)-O-β-D-glucopyranosyl-(1->1)-2-N-tetracosanoyl-(4E)-sphingenine and O-α-D-mannopyranosyl-(1->3)-O-2)>-O-β-D-mannopyranosyl-(1->4)-O-β-D-glucopyranosyl-(1->1)-2-N-tetracosanoyl-(4E)-sphingenine, were synthesized for the first time by using 2,3,4-tri-O-acetyl-D-xylopyranosyl trichloroacetimidate, methyl 2,3,4,6-tetra-O-acetyl-1-thio-α-D-mannopyranoside, benzyl O-(4,6-di-O-benzyl-β-D-mannopyranosyl)-(1->4)-2,3,6-tri-O-benzyl-β-D-glucopyranoside 9, and (2S,3R,4E)-2-azido-3-O-(tert-butyldiphenylsilyl)-4-octadecene-1,3-diol 6 as the key intermediates.The hexa-O-benzyl disaccharide 9 was prepared by coupling two monosaccharide synthons, namely, 2,3-di-O-allyl-4,6-di-O-benzyl-α-D-mannopyranosyl bromide and benzyl 2,3,6-tri-O-benzyl-β-D-glucopyranoside.It was demonstrated that azide 6 was highly efficient as a synthon for the ceramide part in the coupling with both glycotriaosyl and glycotetraosyl donors, particularly in the presence of trimethylsilyl triflate.