Salacinol, a new type of alpha-glucosidase inhibitor discovered from the antidiabetic herb, was synthesized for the first time. Under the strategy that salacinol would be synthesized by the coupling reaction between 1,4-epithio-D-arabinitol and the cyclic sulfate of an erythritol derivative, the model coupling reactions between tetrahydrothiophene and versatile cyclic sulfate derivatives were undertaken. These experiments indicated that the 1,3-diol of the cyclic sulfate should be protected with the isopropylidene group, otherwise, even the benzylidene-protected cyclic sulfate decomposed during the reaction. Thus, the salacinol was synthesized using the cyclic sulfate of 1,3-O-isopypropylidene-D-erythritol. The resulting coupling product was deisopropylidenated to afford salacinol. A diastereomer of salacinol was also synthesized. (C) 2000 Elsevier Science Ltd. All rights reserved.
Glycosidase inhibitors and methods of synthesizing same
申请人:Pinto Mario Brian
公开号:US20050065139A1
公开(公告)日:2005-03-24
A method for synthesizing Salacinol, its stereoisomers, and analogues, homologues and other derivatives thereof potentially useful as glycolsidase inhibitors. The compounds of the invention may have the general formula (I) or (II):
The synthetic schemes comprise reacting a cyclic sulfate with a 5-membered ring sugar containing a heteroatom (X). The heteroatom preferably comprises sulfur, selenium, or nitrogen. The cyclic sulfate and ring sugar reagents may be readily prepared from carbohydrate precursors, such as D-glucose, L-glucose, D-xylose and L-xylose. The target compounds are prepared by opening of the cyclic sulfates by nucleophilic attack of the heteroatoms on the 5-membered ring sugars. The resulting heterocyclic compounds have a stable, inner salt structure comprising a heteroatom cation and a sulfate anion. The synthetic schemes yield various stereoisomers of the target compounds in moderate to good yields with limited side-reactions.
K1115 B1, isolated from the broth of Streptomyces species, was found to be a mixture of stereoisomers. Authors synthesized all stereoisomers of K1115 B1 by convergent synthesis coupling a rhamnose derivative, an isobenzofuranone, and a chiral tetraol. Comparison of 1H NMR spectra and optical rotations made it clear that the absolute structures of K1115 B1α (the major isomer) and K1115 B1β (the minor
从链霉菌属菌种的肉汤中分离出的K1115 B 1被发现是立体异构体的混合物。作者通过收敛合成鼠李糖衍生物,异苯并呋喃酮和手性四元醇的方法合成了K1115 B 1的所有立体异构体。比较1 1 H NMR谱和旋光讲明的K1115 B中的绝对结构1α(主要异构体)和K1115乙1β(次要异构体)为:(1 - [R,17小号) -和(1 - [R 17 - [R)-配置。立体异构体的旋光性表明,报道的铝霉素与K1115 B的结构相同1可能是立体异构体的另一种混合物。
Tertiary Amine Promoted Asymmetric Aldol Reaction of Aldehydes
作者:Bartosz Gut、Jacek Mlynarski
DOI:10.1002/ejoc.201500519
日期:2015.8
direct asymmetric self-aldol reactions of various α-oxyaldehydes catalyzed by tertiaryamines have been demonstrated. By using 10 mol-% of quinine catalyst, dimerization products have been prepared in high yields, with good anti-diastereocontrol, and up to 80 % ee. The presented enolate-mediated synthesis of protected tetrose sugars has never been accomplished before by chiral tertiaryamine organocatalysts
reactions enabled the asymmetric synthesis of deoxysugars with >99 % ee. In addition, the direct amino acid catalyzed C(2)+C(2)+C(2) methodology is a new entry for the short, highly enantioselective denovosynthesis of carbohydrate derivatives, isotope-labeled sugars, and polyketide natural products. The one-pot asymmetric denovo syntheses of deoxy and polyketide carbohydrates involved a novel dynamic kinetic
Highlysyn-selective cross-aldol reaction of aldehydes has remained a challenging subject in the field of aminocatalysis. To achieve this end, chiral primary amines have been explored and the primary−tertiary diamine−Brønsted acid salts are found to promote the cross-aldol reactions of aldehydes with high activity and syn selectivity. Among various vicinal diamines screened, l-phenylalanine derived