1-[(2-Acetoxyethoxy)methyl]-3-methyl-5-bromo-6-azauracil

The product 2 was prepared via a direct condensation under solid-liquid phase transfer catalysis (S.L.P.T.C.) [1] conditions. To a solution of 0.02 mmole of tetraglyme in 4 ml of anhydrous THF, 0.11 mmole of potassium tert-butoxide is added. Then 0.1 mmole of the acyclonucleoside 1 [2] is added, the reaction mixture is stirred at room temperature for 15 min. The reaction mixture is cooled to 0°C and 0.11 mmole of alkylating agent in 2 ml of dry THF is added dropwise with stirring. When the addition is finished, the reaction mixture is stirred at 0°C for 30 min. The reaction mixture is then filtered and the filtrate is evaporated in vacuo to dryness. The residue is then chromatographed on a silica gel column and the expected acyclonucleoside 2 was isolated. Yield: 80 % (viscous and colourless)

Rf: 0.63 (CHCl₃ / MeOH, 9/1, V/V).

¹H NMR (DMSO-d6): 2.00 (s, 3H, COOCH₃); 3.60 (s, 3H, CH₃); 3.70 (m, 2H, OCH₂CH₂O); 4.10 (m, 2H, OCH₂CH₂O); 5.25 (s, 2H, OCH₂N).

UV (l max (nm), H₂O): 288.

MS (m/z): 321 [M (⁷⁹Br)]⁺, 323 [M (⁸¹Br)]⁺

Anal. calc. for C₉H₁₂BrN₃O₅: C 33.55, H 3.75, N 13.04; Found: C 33.54, H 3.75, N 12.75.