Oxalic Acid → 2-(3-Bromophenyl)benzimidazole

HRID 77065

Reaction equation

HRID 77065 reaction equation
[2H][C:2]1[C:7]([2H])=[C:6]([NH2:9])[C:5]([NH2:10])=[C:4]([2H])[C:3]=1[2H].C(O)(=O)C(O)=O.[Br:19][C:20]1[CH:21]=[C:22]([CH:25]=[CH:26][CH:27]=1)[CH:23]=O>C(O)C.O>[Br:19][C:20]1[CH:21]=[C:22]([C:23]2[NH:10][C:5]3[CH:4]=[CH:3][CH:2]=[CH:7][C:6]=3[N:9]=2)[CH:25]=[CH:26][CH:27]=1

Participants

5

Reactant 3

HCID 971Oxalic AcidHCID 765833-BromobenzaldehydeHCID 107729501,2-Diaminobenzene (D4, 98%)

Product 1

HCID 2788222-(3-Bromophenyl)benzimidazoleYield 26.6%

Reagents, catalysts & solvents 1

HCID 19096565Water ethanolSolvent

Conditions

Temperature
80 °C

Procedure

Method 1—Step a O-phenylenediamine (81.8 g, 756.6 mmol) and oxalic acid (3.40 g, 37.8 mmol) were completely dissolved in EtOH—H2O/1:1 (2 L) previously warmed at 80° C. 3-Bromobenzaldehyde (44.10 mL, 378.30 mmol) was then added dropwise to the solution. The reaction mixture was stirred overnight at 70° C. to the open air. The day after solid was filtered off and triturated with MeOH (150 mL) to give the product as a pale yellow solid (27.50 g). 3.8 g were recovered from the mother liquors. Total yield 31.30 g (30%).

Workup

  1. filtrationThe day after solid was filtered off
  2. customtriturated with MeOH (150 mL)

Sources & evidence

ORD record
ord-deb0a06724304497a43c4cc34d772a92
Source dataset
uspto-grants-2014_09
Patent number
US08835648B2

Linked notes

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