Sodium Iodide → HCID 10435134, compound

HRID 1377471Notes

Reaction equation

HRID 1377471 reaction equation
[Cl:1][C:2]1[C:11]([Cl:12])=[CH:10][C:5]2=[N:6][C:7](=[S:9])[N:8]=[C:4]2[CH:3]=1.C[Si](C)(C)N[Si](C)(C)C.Br[C:23]1([O:36][C@H:35]([CH2:37][O:38][C:39](=[O:41])[CH3:40])[C@@H:30]([O:31][C:32](=[O:34])[CH3:33])[C@H:25]1[O:26][C:27](=[O:29])[CH3:28])O.[I-].[Na+]>C(Cl)(Cl)Cl>[Cl:1][C:2]1[C:11]([Cl:12])=[CH:10][C:5]2[N:6]([C@@H:23]3[O:36][C@H:35]([CH2:37][O:38][C:39](=[O:41])[CH3:40])[C@@H:30]([O:31][C:32](=[O:34])[CH3:33])[C@H:25]3[O:26][C:27](=[O:29])[CH3:28])[C:7](=[S:9])[NH:8][C:4]=2[CH:3]=1

Participants

6

Reactant 4

HCID 5238Sodium IodideHCID 13838HexamethyldisilazaneHCID 18421922HCID 18421922, compoundHCID 53847180HCID 53847180, compound

Product 1

HCID 10435134HCID 10435134, compound

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent

Procedure

A mixture of dry 5,6-dichlorobenzimidazole-2-thione (3, 2.19 g 10 mmole), hexamethyldisilazane (4 ml) and (NH4)2SO4 (0.1 g) was heated at reflux temperature with stirring for 15 hr under anhydrous conditions. The clear brown reaction mixture was fractionated to remove unreacted HMDS under reduced pressure (water aspirator) to afford the disilylated compound. The silylated compound was mixed with 1-bromo-2,3,5-tri-O-acetyl-D-ribofuranose (from 3.5 g (11 mmole) of tetraacetylsugar) and sodium iodide (0.05 g). The mixture was then fused at 110° C. (oil bath temperature) with stirring for 45 minutes under reduced pressure. The reaction mixture which had been cooled to room temperature was dissolved in CHCl3. The CHCl3 solution was washed with a cold saturated aqueous sodium bicarbonate solution (100 ml×4) and then cold water (100 ml×4). The CHCl3 phase was dried over Na2SO4 and evaporated on a water bath (40° C.) to dryness to yield a syrup [5,6-dichloro-1-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl) benzimidazole-2-thione]. The syrup was dissolved in methanolic ammonia (methanol saturated with ammonia at 0° C., 100 ml) and allowed to stand at room temperature for 24 hours. After the methanolic ammonia had been removed at room temperature, a syrup remained which was triturated with cold water (30 ml). The solid material (2.548 g) which separated was collected by filtration and was applied to a flash column chromatography on silica gel with CH2Cl2 -MeOH (15:1) as eluant. Fractions were collected (25 ml each), and fractions containing the desired compound were combined and evaporated to obtain 53 which was crystallized from aq. EtOH. Overall yield 2.0 g, 57.0%, mp 241° C.

Workup

  1. temperaturewas heated
  2. temperatureat reflux temperature
  3. customto remove unreacted HMDS under reduced pressure (water aspirator)
  4. customto afford the disilylated compound
  5. customwas then fused at 110° C.
  6. stirringwith stirring for 45 minutes under reduced pressure
  7. washThe CHCl3 solution was washed with a cold saturated aqueous sodium bicarbonate solution (100 ml×4)
  8. dry with materialThe CHCl3 phase was dried over Na2SO4
  9. customevaporated on a water bath (40° C.) to dryness

Sources & evidence

ORD record
ord-ee89c007ff0a47a783ed2515988d8b74
Source dataset
uspto-grants-1997_09
Patent number
US05665709

Reaction notes

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