A New Approach to the Synthesis of Benzothiazole, Benzoxazole, and Pyridine Nucleosides as Potential Antitumor Agents
摘要:
A modified nitrogen and sulfur glycosylation reaction involving benzothiazole benzoxazole and pyridine nucleoside bases with furanose and pyranose sugars are described. Conformational analysis has been studied by homo- and hetero-nuclear two-dimensional NMR methods (2D DFQ-COSY, HMQC and HMBC). The N and S sites of glycosylation were determined from the H-1, C-13 hetero-nuclear multiple-quantum coherence (HMQC) experiments. All the deprotected nucleosides were tested for their potential antitumor activity.
Modelling nucleophilic substitution at silicon using hypervalent silicon compounds based on di and tri halosilanes
作者:Alan R. Bassindale、Moheswar Borbaruah、Simon J. Glynn、David J. Parker、Peter G. Taylor
DOI:10.1016/s0022-328x(00)00263-1
日期:2000.7
range of N-(amidomethyl)-polyhalosilanes have been measured in solution and the extent of SiO bond formation and pentacoordination determined. The larger the number of electronegative groups attached to the silicon the greater the extent of pentacoordination achievable by the silicon. Thus with trichlorosilanes a ‘tight’ pentacoordinate silicon is observed where the SiO bond is almost fully formed.