Water → 2-(2-Thienylcarbonyl)benzoic acid

HRID 54971Notes

Reaction equation

HRID 54971 reaction equation
[C:1]1(=[O:11])[O:6][C:4](=[O:5])[C:3]2=[CH:7][CH:8]=[CH:9][CH:10]=[C:2]12.[Cl-].[Al+3].[Cl-].[Cl-].[S:16]1[CH:20]=[CH:19][CH:18]=[CH:17]1.O>[N+](C1C=CC=CC=1)([O-])=O>[S:16]1[CH:20]=[CH:19][CH:18]=[C:17]1[C:4]([C:3]1[CH:7]=[CH:8][CH:9]=[CH:10][C:2]=1[C:1]([OH:6])=[O:11])=[O:5]

Participants

6

Reactant 4

HCID 962WaterHCID 6811Phthalic AnhydrideHCID 8030ThiopheneHCID 6451240Aluminum(III) Chloride

Product 1

HCID 2826542-(2-Thienylcarbonyl)benzoic acidYield 27%

Reagents, catalysts & solvents 1

HCID 7416NitrobenzeneSolvent

Procedure

A solution of 74.1 g (0.5 mole) of phthalic anhydride in 300 mL of nitrobenzene was treated with 147 g (1.1 mole) of aluminum chloride. The solution was stirred for two hours and 42.1 g (0.5 mole) of thiophene was added dropwise over 80 minutes at 40°-45°. The reaction was stirred at 50°-55° for two hours and then let sit at room temperature overnight. The reaction was poured into 2.8 L of cold water, stirred, separated, and the nitrobenzene was removed from the nitrobenzene layer by steam distillation. The residue was recrystallized from toluene to provide 31.1 g (27%) of 2-thienoylbenzoic acid, mp 141-143. The thienoylbenzoic acid was treated with methylhydrazine as described in Example 185 to provide 24.4 g (75%) of the phthalazinone product, mp 143-144, after recrystallization from ethyl acetate.

Workup

  1. stirringThe reaction was stirred at 50°-55° for two hours
  2. waitlet sit at room temperature overnight
  3. stirringstirred
  4. customseparated
  5. customthe nitrobenzene was removed from the nitrobenzene layer by steam distillation
  6. customThe residue was recrystallized from toluene

Sources & evidence

ORD record
ord-badfe0d6a3f14dbbb8f39bceae2caad5
Source dataset
uspto-grants-1997_04
Patent number
US05624922

Reaction notes

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