Meclofenamic acid → 2-[(2,6-Dichloro-3-methylphenyl) amino]-benzoic acid, 2-(aminothioxomethyl)hydrazide

HRID 1088290Notes

Reaction equation

HRID 1088290 reaction equation
C(Cl)(=O)C(Cl)=O.[Cl:7][C:8]1[C:13]([CH3:14])=[CH:12][CH:11]=[C:10]([Cl:15])[C:9]=1[NH:16][C:17]1[CH:25]=[CH:24][CH:23]=[CH:22][C:18]=1[C:19](O)=[O:20].CN(C)C=O.[NH2:31][NH:32][C:33]([NH2:35])=[S:34]>C(Cl)Cl.N1C=CC=CC=1>[NH2:35][C:33](=[S:34])[NH:32][NH:31][C:19](=[O:20])[C:18]1[CH:22]=[CH:23][CH:24]=[CH:25][C:17]=1[NH:16][C:9]1[C:10]([Cl:15])=[CH:11][CH:12]=[C:13]([CH3:14])[C:8]=1[Cl:7]

Participants

7

Reactant 4

HCID 4037Meclofenamic acidHCID 6228DimethylformamideHCID 65578Oxalyl chlorideHCID 2723789Thiosemicarbazide

Product 1

HCID 98641092-[(2,6-Dichloro-3-methylphenyl) amino]-benzoic acid, 2-(aminothioxomethyl)hydrazideYield 42.4%

Reagents, catalysts & solvents 2

HCID 1049PyridineSolventHCID 6344DichloromethaneSolvent2×

Conditions

Temperature
0 °C

Procedure

Oxalyl chloride (2.85 g, 22.5 mmol) in 10 ml of methylene chloride is added dropwise to a 0° C. suspension of 2-[(2,6-dichloro-3-methylphenyl)amino]-benzoic acid (3.17 g, 10.6 mmol) and dimethylformamide (830 μl, 10.6 mmol) in 50 ml of methylene chloride. The clear yellow solution is stirred at 0° C. for 15 minutes and then at room temperature for 30 minutes. The solution is then concentrated in vacuo to give a yellow solid. This solid is added in portions to a suspension of thiosemicarbazide (1.95 g, 21.4 mmol) in 20 ml of pyridine. The suspension is stirred at 0° C. for 30 minutes then at room temperature overnight. The reaction mixture is concentrated in vacuo and the residue is partitioned between ethyl acetate and water. The organic layer is concentrated, then slurried with equal volumes of ethyl acetate and hexane. The off-white solid is collected by filtration providing 1.66 g (42%) of 2-[(2,6-dichloro-3-methylphenyl)amino]-benzoic acid, 2-(aminothioxomethyl) hydrazide, mp is undefined.

Workup

  1. waitat room temperature for 30 minutes
  2. concentrationThe solution is then concentrated in vacuo
  3. customto give a yellow solid
  4. stirringThe suspension is stirred at 0° C. for 30 minutes
  5. customat room temperature
  6. customovernight
  7. concentrationThe reaction mixture is concentrated in vacuo
  8. customthe residue is partitioned between ethyl acetate and water
  9. concentrationThe organic layer is concentrated
  10. filtrationThe off-white solid is collected by filtration

Sources & evidence

ORD record
ord-d7bc837529924ea693387075bf18c946
Source dataset
uspto-grants-1990_10
Patent number
US04962119

Reaction notes

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