Acetaldehyde, 2,2-dimethoxy- → N-(1H-benzimidazol-2-ylmethyl)-2,2-dimethoxyethanamine

HRID 908251Notes

Reaction equation

HRID 908251 reaction equation
Cl.Cl.[NH:3]1[C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][C:6]=2[N:5]=[C:4]1[CH2:12][NH2:13].[CH3:14][O:15][CH:16]([O:19][CH3:20])[CH:17]=O.C([O-])(=O)C.[Na+].C([BH3-])#N.[Na+]>CO>[NH:3]1[C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][C:6]=2[N:5]=[C:4]1[CH2:12][NH:13][CH2:17][CH:16]([O:19][CH3:20])[O:15][CH3:14]

Participants

6

Reactant 4

HCID 162650Acetaldehyde, 2,2-dimethoxy-HCID 517045Sodium AcetateHCID 2723957(1H-benzo[d]imidazol-2-yl)methanamine dihydrochlorideHCID 5003444Sodium cyanoborohydride

Product 1

HCID 58024802N-(1H-benzimidazol-2-ylmethyl)-2,2-dimethoxyethanamineYield 72.4%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

To a MeOH 150 mL suspension of 1-(1H-benzimidazol-2-yl)methanamine dihydrochloride (4.0 g, 18.2 mmol) were added dimethoxyacetaldehyde (1.89 g, 18.2 mmol, 60 wt. % solution in water), sodium acetate (7.45 g, 91 mmol) and sodium cyanoborohydride (9.09 mL, 9.09 mmol, 1.0 M THF solution). The reaction mixture was stirred at room temperature overnight, concentrated under reduced pressure and reconstituted in DCM (150 mL). The resulting suspension was filtered. The filtrate was concentrated and chromatographed on silica gel with a gradient solvent mixture (5% MeOH-DCM to 15% MeOH-DCM over 15 CV) to give the title compound as oil (3.1 g). LC/MS: m/z 205(M+-OMe). 1H-NMR (CDCl3, 500 MHz) δ 3.02 (d, 1H), 3.36 (s, 6H), 4.40 (s, 211), 4.52 (t, 1H), 7.28-7.32 (m, 2H), 7.58-7.62 (m, 2H), 8.78-8.92 (br.s, 1H).

Workup

  1. concentrationconcentrated under reduced pressure
  2. filtrationThe resulting suspension was filtered
  3. concentrationThe filtrate was concentrated
  4. customchromatographed on silica gel with a gradient solvent mixture (5% MeOH-DCM to 15% MeOH-DCM over 15 CV)

Sources & evidence

ORD record
ord-535d95bce4234cb29bdf23169f3a3d12
Source dataset
uspto-grants-2011_09
Patent number
US08017605B2

Reaction notes

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