General Papers ARKIVOC 2002 (x) 1-8
NMR (DMSO-d6) d 38.6 (2F), 46.0 (2F), 82.5 (3F); EI-MS m/z 139 (100), 383 (20, M+ + 1). Analysis. Calcd. for C12H13F7N2O4: C, 37.71; H, 3.43; N, 7.33. Found: C, 37.64; H, 3.47; N,
7.16. 5-(1,1-Diethoxyperfluorohexyl)uracil (7b). Yield 84%; mp 245-246 °C; 1H NMR (DMSO-d6) d 1.16 (t, J = 7 Hz, 6H), 3.56 (m, 4H), 7.56 (s, 1H), 11.2 (bs, exchangeable with D2O, 2H); 19F NMR (DMSO-d6) d 36.8 (2F), 40.5 (2F), 42.4 (2F), 46.7 (2F), 82.3 (3F); EI-MS m/z 139 (100), 483 (25, M+ + 1). Analysis. Calcd. for C14H13F11N2O4: C, 34.87; H, 2.72; N, 5.81. Found: C, 35.02; H, 2.76; N, 5.77. Acetals 8a,b
Sodium benzyloxide prepared from sodium hydride (120 mg, 5 mmol) and benzyl alcohol (5 mL) was allowed to react with 3 (1 mmol) in benzyl alcohol (5 mL) and the mixture was worked up as described above. The product was crystallized from ether. 5-(1,1-Dibenzyloxyperfluorobutyl)uracil (8a). Yield 66%; mp 225-227 °C; 1H NMR (DMSOd6) d 4.63 (d, J = 11.5 Hz, 2H), 4.77 (d, J = 11.5 Hz, 2H), 7.36 (m, 10H), 7.65 (s, 1H), 11.3 (bs, exchangeable with D2O, 2H); 19F NMR (DMSO-d6) d 38.6 (2F), 46.4 (2F), 82.5 (3F); EI-MS m/z 308 (100), 507 (10, M+ + 1). Analysis. Calcd. for C22H17F7N2O4: C, 52.18; H, 3.38; N, 5.53. Found: C, 52.46; H, 3.33; N, 5.57. 5-(1,1-Dibenzyloxyperfluorohexyl)uracil (8b). Yield 63%; mp 224-225 °C; 1H NMR (DMSOd6) d 4.62 (d, J = 11.5 Hz, 2H), 4.76 (d, J = 11.5 Hz, 2H), 7.36 (m, 10H), 7.66 (s, 1H), 11.3 (bs, exchangeable with D2O, 2H); 19F NMR (DMSO-d6) d 36.9 (2F), 40.6 (2F), 42.5 (2F), 47.1 (2F),
82.3 (3F). Analysis. Calcd. for C24H17F11N2O4: C, 47.54; H, 2.83; N, 4.62. Found: C, 47.69; H, 2.86; N, 4.64. 5-(2-Heptafluoropropyl-4-hydroxymethyl-1,3-dioxolan-2-yl)uracil (9). A mixture of glycerol (5 mL) and metallic sodium (0.115g, 5 mmol) was stirred at 23 oC until evolution of hydrogen ceased and then treated with a solution of 3a (0.33g, 1 mmol). The mixture was heated to 150 oC for 8 h, concentrated by distillation of glycerol on a Kugelrohr, and the residue was dissolved in water (6 mL). The solution was neutralized with hydrochloric acid (1 M) and concentrated on a rotary evaporator to 4 mL. The resultant precipitate of 9 was filtered and crystallized from EtOH: yield 0.195g (51%); mp 273-274 oC; 1H NMR (DMSO-d6) d 3.50 (m, 2H), 3.80 (m, 1H), 4.24 (m, 2H), 5.01(bs, exchangeable with D2O, 1H), 7.56(dd, JH-F = 29 Hz, JH-F = 6 Hz, 1H) 11.20 (bs, exchangeable with D2O, 2H); 19F NMR (DMSO-d6) d 38.2 (2F), 44.3 (2F), 82.2 (3F); ); FAB- MS (thioglycerol) m/z 383 (100, M+ + 1), 308 (60). Analysis. Calcd. for C11H9F7N2O5: C, 34.56; H, 2.37; N, 7.32. Found: C, 34.76; H, 2.37; N, 7.25.
2-Ethoxy-5-(perfluoroalkyl)pyrimidines 11a,b
5-Bromopyrimidin-2(1H)one was obtained by the following modification of the published procedure.20 Pyrimidin-2(1H)one hydrochloride (5.0 g, 38 mmol) was added gradually at 23 °C to a stirred solution of bromine (9.0 g, 56 mmol) in water (100 mL) and then the mixture was
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