A new synthetic route for the preparation of larger quantities
of the anticancer nucleoside analogue 3′-C-ethynylcytidine
is described. Starting from cytidine which was orthogonally protected in
three steps, the ketonucleoside analogue as the key intermediate was
obtained through oxidation of the unprotected 3′-hydroxy group.
Stereoselective addition of the trimethylsilyl-protected acetylide
residue at the 3′-carbonyl group followed by a complete deprotection
afforded 3′-C-ethynylcytidine
in an overall yield of 24% in seven steps.
drugs - nucleosides - stereoselectivity - ketones - oganometallic ragents
