5'-O-(4,4'-Dimethoxytrityl)thymidine → 3'-O-[(6-nitroveratryl)oxycarbonyl]thymidine

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A solution of 1.97 g 5′-O-(4,4′-dimethoxytrityl)thymidine (3.62 mmol) in 18 ml absolute dichloromethane and 2 ml absolute pyridine is added in a nitrogen atomsphere and in the absence of light to an N-methyl-N3-[(6-nitroveratryl)oxycarbonyl]imidazoliumchloride acylation reaction (19) (produced from 7.25 mmol chloroformic acid-6-nitroveratryl ester). The reaction mixture is stirred in the dark at 4° C. overnight. The molecular sieve is separated and the organic phase is extracted twice against saturated NaHCO3 (100 ml). After drying via Na2SO4, 200 ml of a 10% trichloroacetic acid in dichloroethane are added to the organic phase and stirred at room temperature for 5 minutes. The deep-red solution is extracted twice with saturated NaHCO3 (200 ml), the organic phase is dried via Na2SO4 and evaporated. Purification via flash chromatography (66-80% ethyl acetate in toluene) yielded 1.153 g of the title compound (66% yield)

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