Trimethylsilyl triflate → HCID 23383154, compound

HRID 2266945Notes

Reaction equation

HRID 2266945 reaction equation
[Br:1][C:2]1[NH:3][C:4]2[CH:10]=[C:9]([Cl:11])[C:8]([Cl:12])=[CH:7][C:5]=2[N:6]=1.O([Si](C)(C)C)S(C(F)(F)F)(=O)=O.C(O[C@@H:29]1[O:46][CH2:45][C@@H:40]([O:41][C:42](=[O:44])[CH3:43])[C@@H:35]([O:36][C:37](=[O:39])[CH3:38])[C@H:30]1[O:31][C:32](=[O:34])[CH3:33])(=O)C.C(=O)(O)[O-].[Na+]>ClCCCl>[Br:1][C:2]1[N:3]([C@@H:45]2[O:46][CH2:29][C@@H:30]([O:31][C:32](=[O:34])[CH3:33])[C@@H:35]([O:36][C:37](=[O:39])[CH3:38])[C@H:40]2[O:41][C:42](=[O:44])[CH3:43])[C:4]2[CH:10]=[C:9]([Cl:11])[C:8]([Cl:12])=[CH:7][C:5]=2[N:6]=1

Participants

6

Reactant 4

HCID 65367Trimethylsilyl triflateHCID 97336β-D-Ribopyranose, 1,2,3,4-tetraacetateHCID 4660172-bromo-5,6-dichloro-1H-benzimidazoleHCID 516892Sodium Bicarbonate

Product 1

HCID 23383154HCID 23383154, compoundYield 56%

Reagents, catalysts & solvents 1

HCID 111,2-DichloroethaneSolvent

Procedure

2-Bromo-5,6-dichlorobenzimidazole (4.0 g, 15 mmol), N,O-bis(trimethylsiyl)acetamide (Aldrich, 3.7 mL, 15 mmol), and 1,2-dichloroethane (Aldrich Sure Seal, 75 mL) were combined and refluxed under nitrogen for 0.5 h. The solution was cooled to room temperature and trimethylsilyl triflate (Aldrich, 3.2 ml, 16 mmol) was added. Immediately, 4.8 g (15 mmol) solid 1,2,3,4-tetra-O-acetyl-b-D-ribopyranose (beta-D-ribopyranose 1,2,3,4-tetraacetate, Aldrich, Milwaukee) was added. The solution was stirred under nitrogen at reflux for 0.5 h, then poured into 7% aqueous sodium bicarbonate and extracted with dichloromethane. The organic layers was dried with magnesium sulfate (anhyd.), filtered, and evaporated. The crude residue was purified on a silica gel column (5×20 cm, 230-400 mesh) with CH2Cl2 to give 2-bromo-5,6-dichloro-1-(2,3,4-tri-O-acetyl-β-D-ribopyranosyl)-1H-benzimidazole which was fractionated in two parts based on elution. The faster product fraction was impure (1.9 g) and purified by a second column to give 1.4 g (2.7 mmol); the slower product fraction was (3.0 g, 5.7 mmol) for a total yield of 56%; m.p. 100-110° C.; 1H NMR (DMSO-d6) δ 8.39 (s, 1H), 7.91 (s, 1H), 5.95-5.92 (d, 1H, J=9.6 Hz), 5.73-5.70 (d, 1H, J=9.6 Hz), 5.67 (bs, 2H), 4.13-4.09 (dd, 1H, J=6.3 Hz and J=5.8 Hz), 4.00-3.95 (overlapping dd, 1H), 2.19 (s, 3H), 1.98 (s, 3H), 1.74 (s, 3H).

Workup

  1. temperaturerefluxed under nitrogen for 0.5 h
  2. temperatureat reflux for 0.5 h
  3. extractionextracted with dichloromethane
  4. dry with materialThe organic layers was dried with magnesium sulfate (anhyd.)
  5. filtrationfiltered
  6. customevaporated
  7. customThe crude residue was purified on a silica gel column (5×20 cm, 230-400 mesh) with CH2Cl2

Sources & evidence

ORD record
ord-262ec69af65d465c9d778c4ef839adbb
Source dataset
uspto-grants-2010_12
Patent number
US07858773B2

Reaction notes

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