Reacción #3746

Ecuación de reacción

methanol

Triethylamine

thymidine

4,4'-dimethoxytrityl chloride

→

5

Rendimiento 85.3%

5'-O-(4,4'-dimethoxytrityl) thymidine

Rendimiento 85.3%

Disolventes

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.STIRRINGThe solution was stirred at room temperature for 2 hours
2. 2
   workup.ADDITIONwas added
3. 3
   Otroto consume the excess DMTrCl
4. 4
   workup.STIRRINGThe mixture was stirred for 5 minutes
5. 5
   Otrothe solvent removed by rotary evaporation
6. 6
   workup.DISSOLUTIONThe residue was dissolved in 250 ml of ethyl acetate
7. 7
   Lavadothe solution was washed with saturated NaHCO3
8. 8
   Secadodried over MgSO4
9. 9
   OtroThe solid was recrystallized from ethyl acetate/hexane

Procedimiento

Triethylamine (10 ml) in 200 ml THF was injected into a solid mixture of 6.8 g (28.0 mmol) thymidine and 10.2 g (28.6 mmol) 4,4'-dimethoxytrityl chloride under nitrogen with stirring. The solution was stirred at room temperature for 2 hours. After completion of the reaction, 10 ml methanol was added to consume the excess DMTrCl. The mixture was stirred for 5 minutes and the solvent removed by rotary evaporation. The residue was dissolved in 250 ml of ethyl acetate and the solution was washed with saturated NaHCO3 and dried over MgSO4. The solid was recrystallized from ethyl acetate/hexane to obtain 13.0 g 5'-protected thymidine 16 (85.6%).: m.p. 124°-126° C.; 1H NMR (200 MHz, CDCl3) δ8.97 (s, 1H, NH), 7.60 (m, 1H, H-6), 6.72-7.42 (m, 13H, Ph), 6.42 (m, 1H, H-1'), 4.56 (m, 1H, H-3'), 4.05 (m, 1H, H-4'), 3.78 (s, 6H, OMe2), 3.41 (m, 2H, H-5'), 2.62 (m, 1H, OH), 2.46 (m, 2H, H-2'), 1.46 (s, 3H, Me); 13C NMR (50 MHz, CDCl3) δ163.0 (C-4), 157.6, 149.8 (C-2), 143.5, 135.0 (C-6), 134.7, 134.6, 129.4, 127.4, 127.3, 126.5, 112.8, 110.9 (C-5), 86.7 (C-4'), 86.2, 84.7 (C-1'), 72.5 (C-3'), 63.8 (C-5'), 55.5 (OCH3), 41.3 (C-2'), 12.5 (CH3).

Fuente