反应详情

5'-O-Dimethoxytritylthymidine (1.6 g, 2.9 mmol) in anhydrous tetrahydrofuran (5 ml) was added dropwise to a well stirred solution at -78° of CH3OPCl2 (0.33 ml, 2.5 mmol) and collidine (1.86 ml, 14.1 mmol) in anhydrous tetrahydrofuran (5 ml). A white precipitate formed during the addition. The mixture was stirred for 15 min at -78° and then filtered through a sintered glass funnel to remove collidine hydrochloride. The collidine hydrochloride was washed with dry tetrahydrofuran (1 ml). The filtrate was then diluted with dry toluene and concentrated to a gum. After dry argon had been bled into the apparatus, a solution (6 ml) containing toluene:tetrahydrofuran (2:1) was added and the gum was allowed to dissolve completely in this solution. Solvent was removed by concentration in vacuo. This reconcentration using a solution of toluene and tetrahydrofuran was repeated three times. After the final concentration, the gum was dissolved in dry tetrahydrofuran (3 ml), cooled to -78° and a solution of tetrazole (0.18 g, 2.6 mmol) in dry tetrahydrofuran (3 ml) was added dropwise. A white precipitate of collidine hydrochloride formed during the addition. The mixture was stirred additional 10 min at -78° and then transferred using positive argon pressure and a cannula to a centrifuge tube filled with argon. The supernatant recovered after centrifugation contained the tetrazolylphosphite product which can be used directly for synthesis of deoxyoligonucleotides. Alternatively, the tetrazolylphosphite can be stored as a precipitate and reconstituted as needed.

1. customA white precipitate formed during the addition
2. filtrationfiltered through a sintered glass funnel
3. customto remove collidine hydrochloride
4. washThe collidine hydrochloride was washed with dry tetrahydrofuran (1 ml)
5. additionThe filtrate was then diluted with dry toluene
6. concentrationconcentrated to a gum
7. additiona solution (6 ml) containing toluene:tetrahydrofuran (2:1)
8. additionwas added
9. dissolutionto dissolve completely in this solution
10. customSolvent was removed by concentration in vacuo
11. concentrationAfter the final concentration
12. dissolutionthe gum was dissolved in dry tetrahydrofuran (3 ml)
13. temperaturecooled to -78°