Acetic Acid → 2-Butyl-5-cyano-4-(1H-pyrrol-1-yl)imidazole

HRID 248617Notes

Reaction equation

HRID 248617 reaction equation
C([O-])(=O)C.[K+].C(O)(=O)C.[NH2:10][C:11]1[N:12]=[C:13]([CH2:18][CH2:19][CH2:20][CH3:21])[NH:14][C:15]=1[C:16]#[N:17].CO[CH:24]1[CH2:28][CH2:27][CH:26](OC)O1>ClCCl>[CH2:18]([C:13]1[NH:14][C:15]([C:16]#[N:17])=[C:11]([N:10]2[CH:24]=[CH:28][CH:27]=[CH:26]2)[N:12]=1)[CH2:19][CH2:20][CH3:21]

Participants

6

Reactant 4

HCID 176Acetic AcidHCID 790982,5-DimethoxytetrahydrofuranHCID 517044Potassium AcetateHCID 191069144-Amino-2-butyl-5-cyanoimidazole

Product 1

HCID 149628802-Butyl-5-cyano-4-(1H-pyrrol-1-yl)imidazole

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

A solution of potassium acetate (5.0 g), acetic acid (22 mL) and 4-amino-2-butyl-5-cyanoimidazole (Example 7, 1.45 g) was heated to reflux and treated with 2,5-dimethoxy-tetrahydrofuran (1.25 mL). The reaction was held at reflux for 1 minute then cooled back to room temperature with an ice bath. The majority of the acetic acid was evaporated at reduced pressure then the residue was partitioned between ethyl acetate and 10% aqueous K2CO3 (120 mL) each. The organic layer was dried over MgSO4 and evaporated. The residue was purified by flash chromatography on silica gel, eluting with hexane-ethyl acetate (90:10 to 80:20). Evaporation of solvents gave a gum that was redissolved in dichloromethane and evaporated once again. The residual oil was held under a vacuum overnight to afford a waxy solid. 1H-NMR (CDCl3) δ 9.9 (br, 1H), 7.4 (s, 2H), 6.3 (s, 2H), 2.7 (t, 2H), 1.7 (m, 2H), 1.4 (m, 2H), 1.0 (t, 3H).

Workup

  1. temperatureto reflux
  2. temperatureat reflux for 1 minute
  3. customThe majority of the acetic acid was evaporated at reduced pressure
  4. customthe residue was partitioned between ethyl acetate and 10% aqueous K2CO3 (120 mL) each
  5. dry with materialThe organic layer was dried over MgSO4
  6. customevaporated
  7. customThe residue was purified by flash chromatography on silica gel
  8. washeluting with hexane-ethyl acetate (90:10 to 80:20)
  9. customEvaporation of solvents
  10. customgave a gum that
  11. customevaporated once again
  12. customwas held under a vacuum overnight
  13. customto afford a waxy solid

Sources & evidence

ORD record
ord-6ca13150efca45cfa38a958581a48c2d
Source dataset
uspto-grants-1993_05
Patent number
US05210211

Reaction notes

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