2-Aminobenzimidazole → 1H-benzimidazol-2-ylthiourea

HRID 447937Notes

Reaction equation

HRID 447937 reaction equation
C1N=C[N:3]([C:6](N2C=NC=C2)=[S:7])C=1.[NH2:13][C:14]1[NH:15][C:16]2[CH:22]=[CH:21][CH:20]=[CH:19][C:17]=2[N:18]=1.C([O-])(=O)C.[NH4+]>C(#N)C>[NH:15]1[C:16]2[CH:22]=[CH:21][CH:20]=[CH:19][C:17]=2[N:18]=[C:14]1[NH:13][C:6]([NH2:3])=[S:7]

Participants

5

Reactant 3

HCID 136242-AminobenzimidazoleHCID 802641,1'-ThiocarbonyldiimidazoleHCID 517165Ammonium Acetate

Product 1

HCID 27710151H-benzimidazol-2-ylthiourea

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent2×

Conditions

Temperature
90 °C

Procedure

0.535 g (3.0 mmol) N,N′-thiocarbonyldiimidazole was dissolved in 5 ml acetonitrile, and to this yellow solution was added drop-wise 0.40 g (3.0 mmol) 2-aminobenzimidazole, suspended in 5 ml acetonitrile, at room temperature. After 30 minutes, a precipitate formed, and the mixture was stirred another 12 hours. After 0.474 g (6.0 mmol) ammonium acetate in substance (German: “in Substanz”) was added to this mixture, the mixture was heated in the microwave (at 100 Watt) 30 minutes long at 90° C. The solvent was removed under vacuum, water was added to the residue and an extraction with dichloromethane (3×30 ml) followed. The combined organic phase was washed once again with water and, after drying over MgSO4, the solvent was removed under vacuum. The product was purified by means of preparative HPLC (Merck: Chromolith RP-18E, 100-25; eluent wasser/acetonitrile/0.1 molar acetic acid). In this single pot procedure, 0.27 g of the N-1H-benzimidazole-2-ylthiourea was directly recovered without isolation of the intermediate.

Workup

  1. customa precipitate formed
  2. customThe solvent was removed under vacuum, water
  3. additionwas added to the residue
  4. extractionan extraction with dichloromethane (3×30 ml)
  5. washThe combined organic phase was washed once again with water
  6. dry with materialafter drying over MgSO4
  7. customthe solvent was removed under vacuum
  8. customThe product was purified by means of preparative HPLC (Merck: Chromolith RP-18E, 100-25; eluent wasser/acetonitrile/0.1 molar acetic acid)
  9. customIn this single pot procedure, 0.27 g of the N-1H-benzimidazole-2-ylthiourea was directly recovered without isolation of the intermediate

Sources & evidence

ORD record
ord-766e3bc6b124407cb85a4f2348c046fd
Source dataset
uspto-grants-2013_07
Patent number
US08481576B2

Reaction notes

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