3.1.2. General Procedure for the Synthesis of Morpholino Nucleosides **11**

Morpholino nucleosides **2A,G,C** (0.1 mmol) were dissolved in 1.5 mL of EtOH, conc. aq. ammonia (3 mL) was added to each solution and the reaction mixtures were stirred at room temperature. After the deblocation of heterocyclic bases was completed (1–2 days), the reaction mixtures were evaporated. Aq. 80% AcOH (1.5 mL) was added to the residues and to the morpholino nucleosides **2U,T,IU,BrU,ClU** (0.1 mmol). In 1.5 h, all reaction mixtures were diluted with water (5 mL) and washed by CH2Cl<sup>2</sup> (5 × 5 mL). Aqueous layers were evaporated, coevaporated with toluene (3 × 5 mL) and again with water (3 × 5 mL). After drying in vacuum, morpholino nucleosides 11 were obtained in a yield of 90% as partial acetate salts.
