Synthesis and evaluation of glycosyl donors with novel leaving groups for transglycosylations employing β-galactosidase from bovine testes
摘要:
Novel aryl beta-D-galactopyranosides were synthesized employing phase-transfer catalysis, and assayed as potential galactose donors in the presence of P-galactosidase from bovine testes using pNP-Gal as a reference. The aglycones were represented mainly by nitrophenols containing halogens, hydroxymethyl, aldehyde, carboxyl, ester or amino functions. An unusual intermolecular acetyl migration onto the benzylic alcohol group was observed during galactosylation of hydroxymethylnitrophenols. Pyridyl glycosides were obtained by reaction with the corresponding silver pyridinolates. Glycosides of halo-, hydroxymethyl- or methoxy-carbonyl-nitrophenols as leaving groups gave virtually the same yields of transglycosylation products. A minor increase was achieved with nitrosalicylaldehyde as leaving group, whereas carboxy or amino derivatives gave very low or no yield of the transglycosylation product. Commercially available donors such as resorufinyl and 4-methylumbelliferyl beta-D-galactopyranosides exhibited a lower transglycosylation potential than these novel pNP-Gal derivatives. (c) 2006 Elsevier Ltd. All rights reserved.
An object of the present invention is to provide a therapeutic agent for ulcerative colitis which allows 5-aminosalicylic acid (5-ASA) useful as a therapeutic agent for ulcerative colitis to be efficiently delivered to the large intestine of the affected site almost without being absorbed or metabolized in the stomach or the upper part of the small intestine and is safe and can be administered over a long term. The present invention relates to 5-ASA into which D-galactose represented by the following general formula [1] has been introduced.
The compound of the present invention can be efficiently delivered to the large intestine of the site of action, and is degraded by the intestinal bacterial flora, whereby 5-ASA as the active ingredient can be produced in the large intestine.
An object of the present invention is to provide a therapeutic agent for ulcerative colitis which allows 5-aminosalicylic acid (5-ASA) useful as a therapeutic agent for ulcerative colitis to be efficiently delivered to the large intestine of the affected site almost without being absorbed or metabolized in the stomach or the upper part of the small intestine and is safe and can be administered over a long term. The present invention relates to 5-ASA into which D-galactose represented by the following general formula [1] has been introduced.
The compound of the present invention can be efficiently delivered to the large intestine of the site of action, and is degraded by the intestinal bacterial flora, whereby 5-ASA as the active ingredient can be produced in the large intestine.