Methanol → 1-(beta-D-Ribofuranosyl)-2,4,5,6-tetrachlorobenzimidazole

HRID 263887Notes

Reaction equation

HRID 263887 reaction equation
C([O:8][C@@H:9]1[C@H:13]([O:14]CC2C=CC=CC=2)[C@@H:12]([CH2:22][O:23]CC2C=CC=CC=2)[O:11][C@H:10]1[N:31]1[C:35]2[CH:36]=[C:37]([Cl:42])[C:38]([Cl:41])=[C:39]([Cl:40])[C:34]=2[N:33]=[C:32]1[Cl:43])C1C=CC=CC=1.B(Cl)(Cl)Cl.C(Cl)Cl.CO>C(Cl)Cl.CCOC(C)=O>[C@@H:10]1([N:31]2[C:35]3[CH:36]=[C:37]([Cl:42])[C:38]([Cl:41])=[C:39]([Cl:40])[C:34]=3[N:33]=[C:32]2[Cl:43])[O:11][C@H:12]([CH2:22][OH:23])[C@@H:13]([OH:14])[C@H:9]1[OH:8]

Participants

6

Reactant 3

HCID 887MethanolHCID 20463568Boron trichloride methylene chlorideHCID 228765561-(2,3,5-Tri-O-benzyl-beta-D-ribofuranosyl)-2,4,5,6-tetrachlorobenzimidazole

Product 1

HCID 541626391-(beta-D-Ribofuranosyl)-2,4,5,6-tetrachlorobenzimidazoleYield 81.4%

Reagents, catalysts & solvents 2

HCID 6344DichloromethaneSolventHCID 8857Ethyl AcetateSolvent

Conditions

Temperature
-78 °C

Procedure

To a solution of 0.565 g (0.858 mmol) of 91a in 8 mL of CH2Cl2, was added dropwise 8.58 mL of 1M BCl3 /CH2Cl2 at -78° C. The reaction mixture was stirred at -78° C. for 2 hr and then at -40° C. for 2 hr. MeOH (2.5 mL) was added dropwise and stirring was continued at -40° C. for 10 min. The reaction mixture was diluted with EtOAc (75 mL). The EtOAc solution was washed with H2O (50 mL), sat. NaHCO3 solution (50 mL), sat. NaCl solution (50 mL), dried (Na2SO4), and evaporated. The residue was suspended in a small amount of CHCl3 and then filtered. The solid product was washed with portions of CHCl3 and recrystallized from MeOH to give 0.271 g (81%) of 92 as white crystals. MP: 172°-175° C. (dec). 1H NMR (DMSO-d6): d 8.62 (s, 1, 7-H), 5.89 (d, 1, 1'-H, J1'-2' =8.0 Hz), 5.52 (d, 1, 2'-OH, J2'-2'OH =6.5 Hz), 5.46 (t, 1, 5'-OH, J5'-5'OH =4.5 Hz), 5.31 (d, 1, 3'-OH, J3'-3'OH =4.5 Hz), 4.39 (m, 1, 2'-H, J2'-3' =5.5 Hz), 4.14 (m, 1, 3'-H, J3'-4' =2.0 Hz), 4.04 (m, 1, 4'-H, J4'-5' =J4'-5" =2.5 Hz), 3.72 (m, 2, 5'-H and 5"-H, J5'-5" =12.0 Hz). 13C NMR (DMSO-d6): d 142.44 (C2), 138.56 (C3a), 131.95 (C7a), 126.91 (C4), 124.52, 122.39 (C5 and C6), 113.55 (C7), 89.58 (C1'), 86.44 (C4'), 71.95 (C2'), 69.53 (C3'), 60.82 (C5'). Anal. Calcd. for C12H10Cl4N2O4 : C, 37.14; H, 2.60; N, 7.22. Found: C, 37.01; H, 2.60; N, 7.01.

Workup

  1. waitat -40° C. for 2 hr
  2. stirringstirring
  3. waitwas continued at -40° C. for 10 min
  4. washThe EtOAc solution was washed with H2O (50 mL), sat. NaHCO3 solution (50 mL), sat. NaCl solution (50 mL)
  5. dry with materialdried (Na2SO4)
  6. customevaporated
  7. filtrationfiltered
  8. washThe solid product was washed with portions of CHCl3
  9. customrecrystallized from MeOH

Sources & evidence

ORD record
ord-9ddd5d907a1b49e7a4387ff4aa33fb41
Source dataset
uspto-grants-1997_07
Patent number
US05646125

Reaction notes

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