Synthesis of "Reversed" and "Double Headed" Nucleosides
摘要:
The synthesis of several partially and fully deprotected ''reversed'' nucleosides are described starting from ''reversed'' 5-iodouracil-1-yl nucleoside 1. The preparation of a novel purine-purine and mixed purine-pyrimidine ''double headed'' nucleosides via ''reversed'' purine nucleoside 12 is also described.
Synthesis and Biological Activity of Reversed Pyrimidine Nucleosides
摘要:
An efficient approach to reversed nucleosides which enables their synthesis in gram quantities is described. N-1'-Pyrimidine reversed nucleosides were prepared by treating of the sodium salt of pyrimidine bases with protected 5-tosyl ribose. Additionally, N-1',N-3'-disubstituted reversed nucleosides were isolated in the condensation reactions with the 5-halogen pyrimidines. Using the Sonogashira coupling of 5'-iodouracil reversed nucleoside with ethynyltrimethyl silane gave 5'-ethynyl derivative which was further transformed into 5'-acetyl reversed nucleoside. Biological activity of deprotected reversed nucleosides was validated on the panel of six human carcinoma cell lines (HeLa, MIAPaCa2, Hep2, NCI-H358, CaCo-2, and HT-29). 5'-Iodouracil derivative displayed moderate growth inhibition activity against human colon carcinoma (CaCo-2) cells.
The ''double headed' nucleosides 10, 11 and 13 bearing pyrimidine or purine bases attached on C-1 and C-5 positions of single ribose unit have been synthesized following a new synthetic strategy. The strategy rests on the introduction of the first nucleo base at C-5 position of the ribose unit giving 'reversed' nucleoside and the subsequent attachment of the second base at C-1 position of the ribose, by classical glycosylation reaction. This order of the base attachments gave much better yields on the ''double headed' nucleosides then previously known C-1 then C-5 order of attachments.