Studies on the Constituents of Broussonetia Species. I. Two New Pyrrolidine Alkaloids, Broussonetines C and D, as .BETA.-Galactosidase and .BETA.-Mannosidase Inhibitors from Broussonetia kazinoki SIEB.
摘要:
从 Broussonetia kazinoki SIEB.(桑科)中分离出了两种新的吡咯烷生物碱--布洛索内酯 C 和 D。通过光谱和化学方法,布鲁索内廷素 C 和 D 分别被配制成 (2R,3R,4R,5R)-2-羟甲基-3,4-二羟基-5-(10-氧代-羟基十三烷基)吡咯烷 (1) 和 (2R,3R,4R,5R)-2-羟甲基-3,4-二羟基-5-(9-氧代-13-羟基十三烷基)吡咯烷 (2)。1 和 2 对 β-半乳糖苷酶和 β-甘露糖苷酶有抑制作用。
Convergent, stereoselective syntheses of the glycosidase inhibitors broussonetines C, O and P
作者:Celia Ribes、Eva Falomir、Juan Murga、Miguel Carda、J. Alberto Marco
DOI:10.1016/j.tet.2009.10.066
日期:2009.12
The first syntheses of the polyhydroxylated alkaloids (iminosugars) broussonetines O and P, glycosidase inhibitors of the pyrrolidine class, have been performed in a convergent, stereocontrolled way from d-serine as the chiral starting material. The synthesis of broussonetin C, a further member of this compound family, is also reported. A cross-metathesis step was one key feature of the synthesis.
Broussonetine C, a member of the Broussonetia class, was first isolated from the branches of Broussonetia Kazinoki (a deciduous tree distributed throughout Japan, China and Taiwan) in 1997 by Kusano et al.([1,2]) and was assigned structure 1. All of the Broussonetines incorporate a 2,3,4,5-tetrasubstituted pyrrolidine unit as a key motif, probably the most synthetically challenging substructure associated with this class of natural product. Significantly, Broussonetine C was found to exhibit unique beta-galactosidase and beta-mannosidase activities.([1,2]) Such properties, coupled with the unique structure assigned to the alkaloid encouraged us to choose 1 as a novel synthetic target. Thus far, only one asymmetric total synthesis of this pyrrolidine alkaloid has been reported. ([3]) In this report we describe a synthesis of 1, starting from D-arabinose.