Water → HCID 22874345, compound

Participants

Reaction Steps

Detritylation of the fully protected monomer was accomplished by stirring a mixture of 831 mg (1 mmol) of 17 in CH2Cl2 /MeOH 4:1 (20 ml) containing 2% of TsOH×H2O for 15 minutes at r.t. The mixture was then diluted with EtOAc (130 ml), washed with saturated NaHCO3 solution (2×60 ml) and back-extracted. The organic layer was dried (MgSO4) and evaporated. The residue of the 5'-OH monomer intermediate was purified by FC (silica gel, 11.5×3 cm, gradient toluene/EtOAc 1:1+6% MeOH) to yield 530 mg (95%) of 18 as an amorphous solid. UV (MeOH): 298 (sh, 3.58), 274 (sh, 4.38), 268 (4.44). 1H-NMR ((D6)DMSO): 10.59 (s, NH); 8.70, 8.61 (2s, H--C(8), H--C(2)); 8.15 (d, 2H o to NO2), 7.61 (d, 2H m to NO2); 5.96 (s, H--C(1')); 5.15 (t, OH--C(5')); 4.74 (m, H--C(2')); 4.38 (m, H--C(4'), OCH2CH2 (6-N)); 3.73 (m, H--C (5')); 3.58 (m, H--C(5')); 3.10 (t, OCH2CH2); 2.27 (m, H--C (3')); 1.90 (m, H--C(3')); 0.82 (s, 9H, t-butyl); 0.00 (s, 2×CH3 at Si). Anal. calc. for C25H34N6O7Si (558.7): C 53.75, H 6.13, N. 15.04; found: C 53.98, H 6.12, N 14.80.

Provenance & Evidence