Hexane → 5,6-Dichloro-2-ethynyl-1-(2,3-di-O-acetyl-5-deoxy-beta-D-ribofuranosyl) 1H-benzimidazole

HRID 2227204Notes

Reaction equation

HRID 2227204 reaction equation
Br[C:2]1[N:6]([C@@H:7]2[O:19][C@H:18]([CH3:20])[C@@H:13]([O:14][C:15](=[O:17])[CH3:16])[C@H:8]2[O:9][C:10](=[O:12])[CH3:11])[C:5]2[CH:21]=[C:22]([Cl:26])[C:23]([Cl:25])=[CH:24][C:4]=2[N:3]=1.[CH3:27][CH2:28]CCCC>Cl[Pd](Cl)([P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)[P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.C(N(CC)CC)C>[Cl:25][C:23]1[C:22]([Cl:26])=[CH:21][C:5]2[N:6]([C@@H:7]3[O:19][C@H:18]([CH3:20])[C@@H:13]([O:14][C:15](=[O:17])[CH3:16])[C@H:8]3[O:9][C:10](=[O:12])[CH3:11])[C:2]([C:27]#[CH:28])=[N:3][C:4]=2[CH:24]=1

Participants

5

Reactant 2

HCID 8058HexaneHCID 699962602-Bromo-5,6-dichloro-1-(5-deoxy-2,3-di-O-acetyl-beta-D-ribofuranosyl)benzimidazole

Product 1

HCID 570077735,6-Dichloro-2-ethynyl-1-(2,3-di-O-acetyl-5-deoxy-beta-D-ribofuranosyl) 1H-benzimidazoleYield 31%

Reagents, catalysts & solvents 2

HCID 178418476HCID 178418476, compoundCatalystHCID 8471TriethylamineSolvent2×

Conditions

Temperature
25 °C

Procedure

2-Bromo-5,6-dichloro-1-(2,3-di-O-acetyl-5-deoxy-beta-D-ribofuranosyl)-1H-benzimidazole (0.43 g, 0.92 mmol), trimethylacetylene (Aldrich, 0.43 ml, 3.0 mmol), bis(triphenylphosphine)palladium(II) chloride (Aldrich, 0.015 g, 0.02 mmol), cuprous iodide (0.01 g, 0.05 mmol) and triethylamine (distilled from CaH, 30 mL) were combined and flushed with argon for 30 min. The solution was stirred at 25° C. for 1 h then warmed to 80° C. After 3 h the reaction mixture was concentrated and taken up in dichloromethane (100 mL) and extracted with 50 mL of 2% EDTA (Aldrich) twice then with 50 mL of H2O. The organic layer was dried with magnesium sulfate (anhyd), filtered, and evaporated. The crude residue was purified on a silica gel column (2.5×16 cm, 230-400 mesh) with 1:2 ethyl acetate: hexane with 0.1 % triethylamine to give the title compound (0.12 g, 0.28 mmol, 31%); MS (ES+): m/z (rel. intensity) 433 (100, M++Na); 1H NMR (DMSO-d6) δ8.12 (s, 1H, ArH), 8.00 (s, 1H, ArH), 6.21 (d, 1H, CH, J=6.1 Hz), 5.65 (apparent triplet, 1H, CH, J=6.8 Hz), 5.20 (apparent triplet, 1H, CH, J=6.5 Hz), 4.23-4.19 (m, CH, 1H), 2.10 (s, 3H, OAc), 1.98 (s, 3H, OAc), 1.53 (d, 3H, CH3, J=6.3 Hz).

Workup

  1. customflushed with argon for 30 min
  2. temperaturethen warmed to 80° C
  3. concentrationAfter 3 h the reaction mixture was concentrated
  4. extractionextracted with 50 mL of 2% EDTA (Aldrich) twice
  5. dry with materialThe organic layer was dried with magnesium sulfate (anhyd)
  6. filtrationfiltered
  7. customevaporated
  8. customThe crude residue was purified on a silica gel column (2.5×16 cm, 230-400 mesh) with 1:2 ethyl acetate

Sources & evidence

ORD record
ord-44a85bec204540cfaf6dbff240d081f3
Source dataset
uspto-grants-2002_07
Patent number
US06413938B1

Reaction notes

Loading…