DIASTEREOSELECTIVE METHOD FOR PREPARING GLYCOSYLATED PURINE OR PYRIMIDINE BASE Russian patent published in 2004 - IPC

FIELD: organic chemistry, heterocyclic compounds, chemical technology. SUBSTANCE: method involves glycosylation of silylated purine or pyrimidine base or its analog, or derivative with compound of the formula (IIa) or (IIb) wherein R₃ means substituted carbonyl or carbonyl derivative; W and X mean sulfur atom, S=O, SO₂ or oxygen atom; L means removing group. Method involves using Lewis-type acid of the formula (III) (values of radicals R₅-R₈ are given in the description). By other variant of method indicated bases, their analogs or derivatives are subjected for glycosylation with a single cleaved ester enantiomer prepared from compound of the formula (IX) in the presence of Lewis-type acid of the formula (III). EFFECT: enhanced optical purity of end compounds. 17 cl, 50 ex