Stereochemical variations on the colchicine motif. Peracid oxidation of thiocolchicone. Synthesis, conformation and inhibition of microtubule assembly
作者:Ulf Berg、H�kan Bladh、Konstantinos Mpampos
DOI:10.1039/b402840f
日期:——
When 7-oxodesacetamidothiocolchicine (1) was treated with various peroxides in order to afford a Baeyer–Villiger rearrangement, a complex mixture of products was formed, which included the sulfoxide, (2) and sulfone, (3). When peracetic acid was used two additional products were formed; a C-ring lactone (4) and a ring-contracted allocolchicine derivative (5). The sulfoxide (2) was semi-preparatively resolved into enantiomers by chromatography on microcrystalline triacetylcellulose. Rotational barriers around the A–C pivot bond of 2, 4 and 5 were determined by dynamic 1H NMR analysis. The compounds 2, 3, 4 and 7a exhibit moderate inhibition of tubulin polymerization, according to in vitro turbidity studies, whereas 5 was inactive.
7-oxodesacetamidothiocolchicine (1) 经各种过氧化物处理以进行拜耳-维利格重排后,生成了一种复杂的混合物,其中包括亚砜 (2) 和砜 (3)。当使用过乙酸时,会生成两种额外的产物:一种 C 环内酯(4)和一种环收缩的异小甘菊碱衍生物(5)。通过在微晶三乙酰纤维素上进行色谱分析,亚砜(2)被半分离成对映体。通过动态 1H NMR 分析确定了 2、4 和 5 的 A-C 枢键周围的旋转障碍。根据体外浑浊度研究,化合物 2、3、4 和 7a 对微管蛋白的聚合有中度抑制作用,而 5 则没有活性。