Methanol → 2-Chloro-5,6-dinitro-1-beta-D-ribofuranosylbenzimidazole

HRID 6347

Reaction equation

HRID 6347 reaction equation
[Cl:1][C:2]1[N:6]([C@@H:7]2[O:27][C@H:26]([CH2:28][O:29]CC3C=CC=CC=3)[C@@H:17]([O:18]CC3C=CC=CC=3)[C@H:8]2[O:9]CC2C=CC=CC=2)[C:5]2[CH:37]=[C:38]([N+:44]([O-:46])=[O:45])[C:39]([N+:41]([O-:43])=[O:42])=[CH:40][C:4]=2[N:3]=1.B(Cl)(Cl)Cl.CO>C(Cl)Cl.CCOC(C)=O>[Cl:1][C:2]1[N:6]([C@@H:7]2[O:27][C@H:26]([CH2:28][OH:29])[C@@H:17]([OH:18])[C@H:8]2[OH:9])[C:5]2[CH:37]=[C:38]([N+:44]([O-:46])=[O:45])[C:39]([N+:41]([O-:43])=[O:42])=[CH:40][C:4]=2[N:3]=1

Participants

6

Reactant 3

HCID 887MethanolHCID 25135Boron TrichlorideHCID 540450672-Chloro-5,6-dinitro-1-(2,3,5-tri-O-benzyl-beta-D-ribofuranosyl)benzimidazole

Product 1

HCID 228814602-Chloro-5,6-dinitro-1-beta-D-ribofuranosylbenzimidazoleYield 77.6%

Reagents, catalysts & solvents 2

HCID 6344DichloromethaneSolventHCID 8857Ethyl AcetateSolvent

Conditions

Temperature
-78 °C

Procedure

To a solution of 0.464 g (0.719 mmol) of 60 in 12 mL of CH2Cl2, was added dropwise 8.4 mL of 1M BCl3 at -78° C. The reaction mixture was stirred at -78° C. for 2 h and then at -40° C. for 2 h. MeOH (5 mL) was added 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 cold H2O (50 mL), sat. NaHCO3 solution (50 mL), sat. NaCl solution (50 mL), dried (Na2SO4), and evaporated. The residue was coevaporated with MeOH (3 x) and then suspended in a small amount of CHCl3 for a few hours. The solid product was filtered to give 0.209 g of 61. This sample was contaminated by a small amount of 2-chloro- 5,6-dinitrobenzimidazole. A part of the sample (0.18 g) was purified on a silica column (2.4×10 cm, eluted with pure EtOAc). Evaporation of the appropriate fractions and crystallization by addition of CHCl3 gave 0.084 g of 61 as a white solid. MP: 132°-135° C. MS: (El) m/e 374.0276 (1%, M+ =374.0265). 1H NMR (DMSO-d6): δ9.18 (s, 1, 7-H), 8.60 (s, 1, 4-H), 6.00 (d, 1, 1'-H, J1'-2' =7.5 Hz), 5.59 (d, 1, 2'-OH, J2'-2'OH =6.0 Hz), 5.52 (t, 1, 5'-OH, J5'-5'OH =4.5 Hz), 5.38 (d, 1, 3'-OH, J3'-3'OH =4.5 Hz), 4.01 (m, 1, 2'-H, J2'-3' =5.5 Hz), 4.16 (m, 1, 3'-H, J3'-4' =2.0 Hz), 4.07 (m, 1, 4'-H, J4'-5" =J4'-5" =2.5 Hz), 3.73 (m, 2, 5'-H and 5"-H, J5'-5" =12.0 Hz). 13C NMR (DMSO-d6): δ146.55 (C2), 142.63 (C3a), 138.90, 138.60 (C5 and C6), 134.12 (C7a), 116.67 (C4), 111.62 (C7), 89.98 (C1'), 86.91 (C4'), 72.86 (C2'). 69.84 (C3'), 60.85 (C5'). Anal. Calcd. for C12H11ClN4O8 : C, 38.47; H, 2.96; N, 14.95. Found: C, 38.46; H, 2.98; N, 14.62.

Workup

  1. waitat -40° C. for 2 h
  2. stirringstirring
  3. waitwas continued at -40° C. for 10 min
  4. washThe EtOAc solution was washed with cold H2O (50 mL), sat. NaHCO3 solution (50 mL), sat. NaCl solution (50 mL)
  5. dry with materialdried (Na2SO4)
  6. customevaporated
  7. waitsuspended in a small amount of CHCl3 for a few hours
  8. filtrationThe solid product was filtered

Sources & evidence

ORD record
ord-888777079fb14ca3a86b3b24b2f9e593
Source dataset
uspto-grants-1993_09
Patent number
US05248672

Linked notes

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