Total synthesis of calonyctin A2, a macrolidic glycolipid with plant growth-promoting activity
摘要:
Calonyctin A2, a tetrasaccharidic glycolipid having a 22-membered macrolidic structure, has been synthesized by the assembly of three 6-deoxygenated thioglycoside intermediates. The short-step synthesis was achieved by preparation of the most complicated b-c disaccharide unit from phenyl 2,2':4,6:4',6'-tri-O-benzylidene-1-thio-beta-D-laminaribioside without any glycosidation reaction and by regioselective macrolactonization. (C) 2000 Elsevier Science Ltd. All rights reserved.
coadministered with antineoplastic agents, is an alternative approach for increasing the success rate of therapy regimes with different drug combinations. This report describes the isolation and structure elucidation of six new resin glycosides from moon vine seeds (Ipomoea alba) as potential mammalian multidrug-resistance-modifying agents. Albinosides IV–IX (1–6), along with the known albinosides I–III (7–9)
In a continuing study on resin glycosides of crude drugs originated from Convolvulaceae plants, we examined the seeds of Cuscuta chinensis. Two novel acylated trisaccharides named cus-1 and cus-2 were isolated, together with a mixture of resin glycoside-like compounds. Their structures were defined as α-L-rhamnopyranosyl-(1→3)-[2-O-(11S)-11-hydroxytetradecanoyl]-[4-O-(2R, 3R)-3-hydroxy-2-methylbutyryl]-α-L-rhamnopyranosyl-(1→2)-[6-O-acetyl]-D-glucopyranose and α-L-rhamnopyranosyl-(1→3)-[2-O-(11S)-11-hydroxyhexadecanoyl]-[4-O-(2R, 3R)-3-hydroxy-2-methylbutyryl]-α-L-rhamnopyranosyl-(1→2)-[6-O-acetyl]-D-glucopyranose, respectively. They are considered to be closely related to so-called resin glycosides in terms of structure and biosynthesis.
Unusual ether-type resin glycoside dimers from the seeds of Cuscuta chinensis
作者:Bo-Yi Fan、Jian-Guang Luo、Yu-Cheng Gu、Ling-Yi Kong
DOI:10.1016/j.tet.2014.01.068
日期:2014.3
Two new resin glycosides, cuses 3 (1) and 4 (2), were initially obtained from the seeds of Cuscutachinensis. Both of them contained a reducing glucose unit, and thus existed as a pair of isomers. In order to solve the existing problem of tautomerism, the remanent resin glycoside fraction was converted into aminoalditol derivatives with p-anisidine, and then another eight new resin glycosides cuses
Calonyctin A2, a tetrasaccharidic glycolipid having a 22-membered macrolidic structure, has been synthesized by the assembly of three 6-deoxygenated thioglycoside intermediates. The short-step synthesis was achieved by preparation of the most complicated b-c disaccharide unit from phenyl 2,2':4,6:4',6'-tri-O-benzylidene-1-thio-beta-D-laminaribioside without any glycosidation reaction and by regioselective macrolactonization. (C) 2000 Elsevier Science Ltd. All rights reserved.