Leflunomide Related Compounds & Impurities

Leflunomide is a DHODH inhibitor prodrug that suppresses pyrimidine synthesis in activated lymphocytes, used for rheumatoid and psoriatic arthritis.

Simson Pharma Limited along with its subsidiary offices Simson Pharma Global Ltd. (UK) and Simson Pharma Global LLC (USA) is a trusted manufacturer and supplier of high-quality pharmaceutical reference standards, offering a comprehensive portfolio of Leflunomide reference standards, pharmacopeial and non-pharmacopeial Leflunomide impurities, related compounds, related substances, metabolites, stable isotope-labelled compounds, deuterium labelled compounds and nitrosamine (N-NO) reference standards.

These materials support pharmaceutical research and development, product development, ANDA and DMF submissions, quality control (QC), analytical method development and validation, stability studies, impurity identification, and genotoxic impurity assessment.

Our Leflunomide-related reference standards are thoroughly characterized using advanced analytical techniques and are supplied with comprehensive Certificates of Analysis (COA) and supporting analytical data from our USFDA certified, ISO 17025 and ISO 17034 accredited Lab, to meet global regulatory expectations. EP and USP traceable reference standards can also be provided upon request, subject to availability. Simson is also a provider of EP and USP traceable standards. To ensure consistent quality and reliability, our reference standards are periodically re-tested according to established quality management procedures.

Pharmaceutical Reference Standards / Impurity Standards

Leflunomide
Leflunomide
  • CAT. No.L500000
  • CAS. No.75706-12-6
  • Mol. F.C12H9F3N2O2
  • Mol. W.270.21 g/mol
  • Stock Status:Instock
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Leflunomide Impurity
Leflunomide Impurity
  • CAT. No.L500001
  • CAS. No.51135-73-0
  • Mol. F.C7H9NO3
  • Mol. W.155.15 g/mol
  • Stock Status:Instock
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Leflunomide Related Compound B
Leflunomide Related Compound B
  • CAT. No.L500002
  • CAS. No.108605-62-5
  • Mol. F.C12H9F3N2O2
  • Mol. W.270.21 g/mol
  • Stock Status:Instock
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Leflunomide EP Impurity C
Leflunomide EP Impurity C
  • CAT. No.L500003
  • CAS. No. 61643-23-0
  • Mol. F.C12H9F3N2O2
  • Mol. W.270.21 g/mol
  • Stock Status:Instock
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Leflunomide EP Impurity A
Leflunomide EP Impurity A
  • CAT. No.L500004
  • CAS. No.455-14-1
  • Mol. F.C7H6F3N
  • Mol. W.161.12 g/mol
  • Stock Status:Instock
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Leflunomide EP Impurity E
Leflunomide EP Impurity E
  • CAT. No.L500005
  • CAS. No.208401-20-1
  • Mol. F.C12H9F3N2O2
  • Mol. W.270.20 g/mol
  • Stock Status:Instock
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Leflunomide EP Impurity H
Leflunomide EP Impurity H
  • CAT. No.L500006
  • CAS. No.24522-30-3
  • Mol. F.C10H7F3N2O
  • Mol. W.228.17 g/mol
  • Stock Status:Instock
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Leflunomide EP Impurity B
Leflunomide EP Impurity B
  • CAT. No.L500007
  • CAS. No.163451-81-8
  • Mol. F.C12H9F3N2O2
  • Mol. W.270.21 g/mol
  • Stock Status:Instock
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Ethyl 3-methylisoxazole-4-carboxylate
Ethyl 3-methylisoxazole-4-carboxylate
  • CAT. No.L500008
  • CAS. No.20328-15-8
  • Mol. F.C7H9NO3
  • Mol. W.155.15 g/mol
  • Stock Status:Under Synthesis
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Leflunomide EP Impurity D
Leflunomide EP Impurity D
  • CAT. No.L500010
  • CAS. No.42831-50-5
  • Mol. F.C5H5NO3
  • Mol. W.127.10 g/mol
  • Stock Status:Instock
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Leflunomide EP Impurity F
Leflunomide EP Impurity F
  • CAT. No.L500011
  • CAS. No.1403564-06-6
  • Mol. F.C12H9F3N2O2
  • Mol. W.270.21 g/mol
  • Stock Status:Custom Synthesis
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Leflunomide EP Impurity G
Leflunomide EP Impurity G
  • CAT. No.L500012
  • CAS. No.724429-16-7
  • Mol. F.C12H12N2O2
  • Mol. W.216.24 g/mol
  • Stock Status:Custom Synthesis
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Teriflunomide Impurity 2
Teriflunomide Impurity 2
  • CAT. No.L500013
  • CAS. No.69066-42-8
  • Mol. F.C9H6F3NO3
  • Mol. W.233.14 g/mol
  • Stock Status:Instock
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3-Methylisoxazole-4-carboxylic Acid
3-Methylisoxazole-4-carboxylic Acid
  • CAT. No.L500014
  • CAS. No.17153-20-7
  • Mol. F.C5H5NO3
  • Mol. W.127.10 g/mol
  • Stock Status:Instock
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Leflunomide Impurity 3
Leflunomide Impurity 3
  • CAT. No.L500015
  • CAS. No.195371-90-5
  • Mol. F.C15H9F6NO
  • Mol. W.333.23 g/mol
  • Stock Status:Instock
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Teriflunomide Impurity 3
Teriflunomide Impurity 3
  • CAT. No.L500016
  • CAS. No.1011244-72-6
  • Mol. F.C14H11F3N2O
  • Mol. W.280.25 g/mol
  • Stock Status:Instock
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Teriflunomide Impurity 16
Teriflunomide Impurity 16
  • CAT. No.L500017
  • CAS. No.349-97-3
  • Mol. F.C9H8F3NO
  • Mol. W.203.16 g/mol
  • Stock Status:Instock
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Teriflunomide Impurity 7
Teriflunomide Impurity 7
  • CAT. No.L500018
  • CAS. No.106-49-0
  • Mol. F.C7H9N
  • Mol. W.107.15 g/mol
  • Stock Status:Custom Synthesis
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2-Chlorobenzotrifluoride
2-Chlorobenzotrifluoride
  • CAT. No.L500019
  • CAS. No.88-16-4
  • Mol. F.C7H4ClF3
  • Mol. W.180.55 g/mol
  • Stock Status:Custom Synthesis
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2-Aminobenzotrifluoride
2-Aminobenzotrifluoride
  • CAT. No.L500020
  • CAS. No.88-17-5
  • Mol. F.C7H6F3N
  • Mol. W.161.12 g/mol
  • Stock Status:Custom Synthesis
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2-cyano-2hydroxy-N-(4-(trifluromethyl)phenyl)acetamide
2-cyano-2hydroxy-N-(4-(trifluromethyl)phenyl)acetamide
  • CAT. No.L500022
  • CAS. No.NA
  • Mol. F.C10H7F3N2O2
  • Mol. W.244.17 g/mol
  • Stock Status:Custom Synthesis
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Teriflunomide Impurity 8
Teriflunomide Impurity 8
  • CAT. No.L500023
  • CAS. No.61865-29-0
  • Mol. F.C7H8FN
  • Mol. W.125.14 g/mol
  • Stock Status:Under Synthesis
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4-Nitrobenzylfluoride
4-Nitrobenzylfluoride
  • CAT. No.L500025
  • CAS. No.500-11-8
  • Mol. F.C7H6FNO2
  • Mol. W.155.12 g/mol
  • Stock Status:Custom Synthesis
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Leflunomide EP Impurity F
Leflunomide EP Impurity F
  • CAT. No.L500027
  • CAS. No.1403564-06-6
  • Mol. F.C12H9F3N2O2
  • Mol. W.270.21 g/mol
  • Stock Status:Instock
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2-Hydroxy-N-(4-trifluoromethyl)phenyl)propanamide
2-Hydroxy-N-(4-trifluoromethyl)phenyl)propanamide
  • CAT. No.L500028
  • CAS. No.NA
  • Mol. F.C10H10F3NO2
  • Mol. W.233.19 g/mol
  • Stock Status:Custom Synthesis
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3-hydroxy-N-(4-(trifluoromethyl)phenyl)propanamide
3-hydroxy-N-(4-(trifluoromethyl)phenyl)propanamide
  • CAT. No.L500029
  • CAS. No.NA
  • Mol. F.C10H10F3NO2
  • Mol. W.233.19 g/mol
  • Stock Status:Custom Synthesis
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Teriflunamide Impurity 4
Teriflunamide Impurity 4
  • CAT. No.L500031
  • CAS. No.1385789-70-7
  • Mol. F.C12H12N2O2
  • Mol. W.216.24 g/mol
  • Stock Status:Instock
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3-Trifluoro Isomer
3-Trifluoro Isomer
  • CAT. No.L500032
  • CAS. No.62004-05-1
  • Mol. F.C12H9F3N2O2
  • Mol. W.270.21 g/mol
  • Stock Status:Instock
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2-Cyano-3-hydroxy-but-2-enoic acid (3-trifluoromethylphenyl)amide
2-Cyano-3-hydroxy-but-2-enoic acid (3-trifluoromethylphenyl)amide
  • CAT. No.L500033
  • CAS. No.NA
  • Mol. F.C12H9F3N2O2
  • Mol. W.270.21 g/mol
  • Stock Status:Custom Synthesis
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Teriflunomide-Ortho-isomer
Teriflunomide-Ortho-isomer
  • CAT. No.L500034
  • CAS. No.220512-86-7
  • Mol. F.C12H9F3N2O2
  • Mol. W.270.21 g/mol
  • Stock Status:Custom Synthesis
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Teriflunamide Impurity 20
Teriflunamide Impurity 20
  • CAT. No.L500035
  • CAS. No.NA
  • Mol. F.C12H10F2N2O2
  • Mol. W.252.20 g/mol
  • Stock Status:Custom Synthesis
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Teriflunamide Impurity 21
Teriflunamide Impurity 21
  • CAT. No.L500036
  • CAS. No.NA
  • Mol. F.C12H11FN2O2
  • Mol. W.234.20 g/mol
  • Stock Status:Custom Synthesis
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(E)-Teriflunomide
(E)-Teriflunomide
  • CAT. No.L500037
  • CAS. No.214782-56-6
  • Mol. F.C12H9F3N2O2
  • Mol. W.270.21 g/mol
  • Stock Status:Custom Synthesis
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Teriflunomide Impurity F
Teriflunomide Impurity F
  • CAT. No.L500038
  • CAS. No.2707-23-5
  • Mol. F.C9H7ClF3NO
  • Mol. W.237.61 g/mol
  • Stock Status:Custom Synthesis
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Teriflunomide impurity G
Teriflunomide impurity G
  • CAT. No.L500039
  • CAS. No.NA
  • Mol. F.C9H6Cl2F3NO
  • Mol. W.272.05 g/mol
  • Stock Status:Custom Synthesis
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4-amino-N,N'-bis(4-(trifluoromethyl)phenyl)benzimidamide(E/Z mixture)
4-amino-N,N'-bis(4-(trifluoromethyl)phenyl)benzimidamide(E/Z mixture)
  • CAT. No.L500040
  • CAS. No.NA
  • Mol. F.C21H15F6N3
  • Mol. W.423.35 g/mol
  • Stock Status:Custom Synthesis
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Teriflunomide Ortho Isomer
Teriflunomide Ortho Isomer
  • CAT. No.L500041
  • CAS. No.220512-86-7
  • Mol. F.C12H9F3N2O2
  • Mol. W.270.21 g/mol
  • Stock Status:Custom Synthesis
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2 cyano-3-hydroxy-N-[3-(trifluoromethyl)phenyl]but-2-enamide
2 cyano-3-hydroxy-N-[3-(trifluoromethyl)phenyl]but-2-enamide
  • CAT. No.L500042
  • CAS. No.NA
  • Mol. F. C12H9F3N2O2
  • Mol. W.270.21 g/mol
  • Stock Status:Instock
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Nitroso-Teriflunomide
Nitroso-Teriflunomide
  • CAT. No.L500043
  • CAS. No.NA
  • Mol. F.C12H8F3N3O3
  • Mol. W.299.21 g/mol
  • Stock Status:Custom Synthesis
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Teriflunomide Impurity 28
Teriflunomide Impurity 28
  • CAT. No.L500044
  • CAS. No.NA
  • Mol. F.C13H8F6N2O2
  • Mol. W.338.21 g/mol
  • Stock Status:Custom Synthesis
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Leflunomide Metabolite Ethyl Analog
Leflunomide Metabolite Ethyl Analog
  • CAT. No.L500045
  • CAS. No.2734292-21-6
  • Mol. F.C13H11F3N2O2
  • Mol. W.284.24 g/mol
  • Stock Status:Custom Synthesis
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Leflunomide EP Impurity A Hydrochloride
Leflunomide EP Impurity A Hydrochloride
  • CAT. No.L500046
  • CAS. No.90774-69-9
  • Mol. F.C7H7ClF3N
  • Mol. W.197.59 g/mol
  • Stock Status:Instock
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Teriflunomide Meta Impurity
Teriflunomide Meta Impurity
  • CAT. No.L500047
  • CAS. No.63927-52-6
  • Mol. F.C12H9F3N2O2
  • Mol. W.270.21 g/mol
  • Stock Status:Instock
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Malonamic Acid
Malonamic Acid
  • CAT. No.L500048
  • CAS. No.2345-56-4
  • Mol. F.C3H5NO3
  • Mol. W.103.08 g/mol
  • Stock Status:Custom Synthesis
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Teriflunomide Ortho Impurity
Teriflunomide Ortho Impurity
  • CAT. No.L500049
  • CAS. No.NA
  • Mol. F.C12H9F3N2O2
  • Mol. W.270.20 g/mol
  • Stock Status:Custom Synthesis
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Teriflunomide Lactose Adduct 1
Teriflunomide Lactose Adduct 1
  • CAT. No.L500050
  • CAS. No.NA
  • Mol. F.C24H29F3N2O12
  • Mol. W.594.50 g/mol
  • Stock Status:Custom Synthesis
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Teriflunomide Lactose Adduct 2
Teriflunomide Lactose Adduct 2
  • CAT. No.L500051
  • CAS. No.NA
  • Mol. F.C24H29F3N2O12
  • Mol. W.594.50 g/mol
  • Stock Status:Custom Synthesis
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Leflunomide Form 1
Leflunomide Form 1
  • CAT. No.L500052
  • CAS. No.75706-12-6
  • Mol. F.C12H9F3N2O2
  • Mol. W.270.21 g/mol
  • Stock Status:Custom Synthesis
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Leflunomide Impurity 4
Leflunomide Impurity 4
  • CAT. No.L500054
  • CAS. No.1903709-86-3
  • Mol. F.C8H7ClF3N
  • Mol. W.209.60 g/mol
  • Stock Status:Custom Synthesis
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Teriflunomide Impurity A
Teriflunomide Impurity A
  • CAT. No.L500055
  • CAS. No.202057-74-7
  • Mol. F.C12H9N3O2
  • Mol. W.227.22 g/mol
  • Stock Status:Custom Synthesis
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Leflunomide Impurity 5
Leflunomide Impurity 5
  • CAT. No.L500056
  • CAS. No.NA
  • Mol. F.C6H7NO3
  • Mol. W.141.12 g/mol
  • Stock Status:Custom Synthesis
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Teriflunomide Impurity 17
Teriflunomide Impurity 17
  • CAT. No.L500058
  • CAS. No.64748-87-4
  • Mol. F.C9H8F3NO
  • Mol. W.203.16 g/mol
  • Stock Status:Custom Synthesis
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Teriflunomide Impurity 1
Teriflunomide Impurity 1
  • CAT. No.L500059
  • CAS. No.1058722-45-4
  • Mol. F.C12H9F3N2O3
  • Mol. W.286.21 g/mol
  • Stock Status:Custom Synthesis
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Teriflunomide Impurity 4
Teriflunomide Impurity 4
  • CAT. No.L500060
  • CAS. No.2809442-03-1
  • Mol. F.C10H7F3N2O2
  • Mol. W.244.17 g/mol
  • Stock Status:Custom Synthesis
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N-Nitroso leflunomide impurity 1
N-Nitroso leflunomide impurity 1
  • CAT. No.L500061
  • CAS. No.NA
  • Mol. F.C12H8F3N3O3
  • Mol. W.299.21 g/mol
  • Stock Status:Custom Synthesis
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Leflunomide Impurity 6
Leflunomide Impurity 6
  • CAT. No.L500062
  • CAS. No.523987-35-1
  • Mol. F.C12H9F3N2O2
  • Mol. W.270.21 g/mol
  • Stock Status:Custom Synthesis
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Leflunomide Impurity 2
Leflunomide Impurity 2
  • CAT. No.L500063
  • CAS. No.NA
  • Mol. F.C12H8ClF3N2O2
  • Mol. W.304.65 g/mol
  • Stock Status:Custom Synthesis
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Isotope Labelled Compounds

Teriflunomide-d4
Teriflunomide-d4
  • CAT. No.L500009
  • CAS. No.1185240-22-5
  • Mol. F.C12H5F3N2O2D4
  • Mol. W.274.24 g/mol
  • Stock Status:Instock
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Leflunomide-D4
Leflunomide-D4
  • CAT. No.L500026
  • CAS. No.1189987-23-2
  • Mol. F.C12H5D4F3N2O2
  • Mol. W.274.23 g/mol
  • Stock Status:Instock
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