1-[(2-Acetoxyethoxy)methyl]-3-benzyl-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: 75 % (viscous and colourless).

Rf: 0.76 (CHCl₃ / MeOH, 9/1, V/V).

¹H NMR (DMSO-d₆): 2.00 (s, 3H, COOCH₃); 3.70 (m, 2H, OCH₂CH₂O); 4.10 (m, 2H, OCH₂CH₂O); 5.10 (s, 2H, CH₂Ph); 5.25 (s, 2H, OCH₂N); 7.14 (sl, 5H, C₆H₅).

UV (λ max (nm), H₂O): 288, 263^sh.

MS (m/z): 397 [M (⁷⁹Br)]⁺, 399 [M (⁸¹Br)]⁺

Anal. calc. for C₁₅H₁₆BrN₃O₅: C: 45.24, H: 4.05, N: 10.55; Found: C: 45.67, H: 4.29, N: 10.18.