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Immunosuppressants Chemical Properties Uses Production method Precautions
Chemical Name:
Arava;HWA 486;RS-34821;LEFLUNOMIDE;Leflunamide;LeflunoMida;LeflunoMideUSP31;Leflunomide, >=99%;Isoxazol lefunomide;Leflunomide (200 mg)
Molecular Formula:
Formula Weight:
MOL File:

Leflunomide Properties

Melting point:
storage temp. 
10.8(at 25℃)
CAS DataBase Reference
75706-12-6(CAS DataBase Reference)
  • Risk and Safety Statements
  • Hazard and Precautionary Statements (GHS)
Hazard Codes  Xn,Xi
Risk Statements  22-36/37/38
Safety Statements  26-36
RIDADR  UN 2811 6.1/PG 3
WGK Germany  3
RTECS  NY2354200
HazardClass  6.1
PackingGroup  III
Hazardous Substances Data 75706-12-6(Hazardous Substances Data)
Signal word: Danger
Hazard statements:
Code Hazard statements Hazard class Category Signal word Pictogram P-Codes
H301 Toxic if swalloed Acute toxicity,oral Category 3 Danger P264, P270, P301+P310, P321, P330,P405, P501
H315 Causes skin irritation Skin corrosion/irritation Category 2 Warning P264, P280, P302+P352, P321,P332+P313, P362
H319 Causes serious eye irritation Serious eye damage/eye irritation Category 2A Warning P264, P280, P305+P351+P338,P337+P313P
H335 May cause respiratory irritation Specific target organ toxicity, single exposure;Respiratory tract irritation Category 3 Warning
H360 May damage fertility or the unborn child Reproductive toxicity Category 1A, 1B Danger
Precautionary statements:
P201 Obtain special instructions before use.
P202 Do not handle until all safety precautions have been read and understood.
P261 Avoid breathing dust/fume/gas/mist/vapours/spray.
P264 Wash hands thoroughly after handling.
P264 Wash skin thouroughly after handling.
P270 Do not eat, drink or smoke when using this product.
P280 Wear protective gloves/protective clothing/eye protection/face protection.
P301+P310 IF SWALLOWED: Immediately call a POISON CENTER or doctor/physician.
P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.
P308+P313 IF exposed or concerned: Get medical advice/attention.
P337+P313 IF eye irritation persists: Get medical advice/attention.
P405 Store locked up.
P501 Dispose of contents/container to..…

Leflunomide price More Price(14)

Manufacturer Product number Product description CAS number Packaging Price Updated Buy
Sigma-Aldrich L5025 Leflunomide Immunosuppressant 75706-12-6 25mg $74 2017-11-08 Buy
Sigma-Aldrich 1356960 Leflunomide United States Pharmacopeia (USP) Reference Standard 75706-12-6 200mg $432.1 2017-11-08 Buy
TCI Chemical L0250 Leflunomide >98.0%(HPLC)(N) 75706-12-6 1g $427 2017-11-08 Buy
TCI Chemical L0250 Leflunomide >98.0%(HPLC)(N) 75706-12-6 200mg $123 2017-11-08 Buy
Alfa Aesar J65917 Leflunomide 75706-12-6 100mg $134 2017-11-08 Buy

Leflunomide Chemical Properties,Uses,Production


Leflunomide is a kind of isoxazole immunosuppressive drugs with anti-proliferative activity , modern pharmacology classifies  this product  as antipyretic, analgesic and anti-inflammatory drugs . This product can be rapidly converted to the active metabolites  and play a role by the liver and intestinal cytoplasm and microsomes , its; main mechanism is  during DNA synthesis, inhibiting a key enzyme-DHODH (DHODH) activity, so that the nucleotides within the B lymphocyte  are depleted , it terminates the biosynthesis of DNA and RNA, the cells can not enter s phase, and ultimately can not proliferate, resulting in anti-rheumatic effects, it is suitable for the treatment of adults with active rheumatoid arthritis, ankylosing spondylitis, it can slow bone destruction, alleviate the symptoms and signs. In addition, leflunomide can also inhibit the tyrosine kinase activity, thereby inhibiting proliferation of T cell, B cell  and non-immune cells, but it can also, by biosynthesis inhibition of cyclooxygenase-2 (COX2) , inhibit prostaglandin synthesis and exert anti-inflammatory effects and inhibit mast cells and basophils histamine release. When  this product is used in organ transplant patients,the  dose adjustment is difficult, it is mainly used to treat rheumatoid arthritis and other autoimmune diseases.
After oral administration of the product, it is rapidly transformed to the active metabolite  in the intestinal wall and liver  , F is 80%,it  does not affect the  absorption of the meal. Tmax is 6~12 h, if the first dose is administered as a loading dose of 100mg, it can reach steady-state plasma concentrations in 3 days, otherwise it needs numbers of months to reach steady-state plasma concentrations. Active metabolite PPB is 99.3%, which is mainly  distributed in the liver, kidney and skin, less in brain tissue. After further metabolization of the active metabolite,  43% of the marker is excreted in the urine of, 48% is excreted by the fecal , T1/2 is about 2 weeks, enterohepatic circulation leads to a longer half-life of the active metabolite  which is the main factor. High-fat diet does not have a big effect on the plasma concentrations of drugs. Activated charcoal or cholestyramine inhibits absorption of the drug.

Chemical Properties

White crystalline powder, melting at 166.5 ℃.


(1) It is hydrogenated acid dehydrogenase inhibitor with immunosuppressive and anti-inflammatory effects for the treatment of adults with active rheumatoid arthritis.
(2) Nonsteroidal anti-inflammatory drug.

Production method

Ethyl acetoacetate, triethyl orthoformate and acetic anhydride are refluxed together to the complete reaction of raw materials, about 5h. Distillate and collect  140 150 ℃/1.87kPa fraction, the compound ( I) is obtained, in 85% yield.
Compound (I) is dissolved in ethanol,the mixture of hydroxylamine hydrochloride, sodium acetate and water is added dropwise at 10-15 ℃ and 1h, After dropping,react for about 8h.Concentrated hydrochloric acid and glacial acetic acid are added ,then reflux  for 5h. Concentrate under reduced pressure to 1/2 volume, cool to 10 ℃, filtration, recrystallize ethanol-water  ,compound (Ⅱ) is obtained, it is white crystalline powder, melting point 145-146.5 ℃, in 80% yield.
Compound (II) is dissolved in toluene and thionyl chloride is added dropwise at 50-55℃, reflux for 3h. After concentration, distillation, collect  78-79 ℃/1.87kPa fraction, the compound (III) is obtained, in 75% yield.
Trifluoromethyl aniline and triethylamine are dissolved  in dichloromethane, at 0-5 ℃ solution ,the compound (Ⅲ) is added. Then at 25--30 ℃ reaction lasts 3h. Water is added, the organic layer is separated, wash with water, wash with brine, and dry. Concentrate under reduced pressure to 1/3 volume, petroleum ether is added, cool, filter, and recrystallize from ethyl acetate to give white crystals powder of leflunomide , m.p. 166~167 ℃, in yield 81%.


1, people who are leflunomide and its metabolites allergy, pregnant women or women who may become pregnant and lactating women are disabled.
2, patients with severe liver damage and hepatitis B or hepatitis C serology markers positive should use with caution. ALT and white cells should be checked regularly during medication.
3, patients with immune deficiency, uncontrolled infection, active gastrointestinal disease, renal insufficiency, bone marrow dysplasia should use with caution.
4. For males who prepare fertility, treatment interruption should be considered, at the same time   cholestyramine should be taken .
5, during treatment of this product, the effect and safety of the immunization live vaccine have  no clinical data, the immunization vaccine should not be used during medication.
6, for children using the product,the safety and efficacy have not been studied, so patients younger than 18 years of age are not recommended to the FDA.
7, if the overdose or toxicity occurs, cholestyramine or activated charcoal  can be administered orally to promote excretion of leflunomide.
8, the active metabolite of the product can cause diclofenac, ibuprofen, tolbutamide plasma concentration increasing from 13% to 50%, while the combination of rifampicin can increase blood concentrations of the active metabolite increasing by about 40% . In addition, the product may increase the liver toxicity of methotrexate.

Chemical Properties

Off White Crystalline Solid


An immunosuppressive. Inhibits T and B cell proliferation. Activity is attributed mainly to its metabolite, a malononitrile derivative, which is beleived to inhibit dihydroorotate dehydrogenase as well as several protein tyrosine kinases. Therapeutical




anti-Altzheimer therapeutic


ChEBI: A monocarboxylic acid amide obtained by formal condensation of the carboxy group of 5-methyl-1,2-oxazole-4-carboxylic acid with the anilino group of 4-(trifluoromethyl)aniline. The prodrug of teriflunomide.

Biological Activity

Immunosuppressant agent. In vitro the active metabolite A77 1726 (RS-61980) inhibits dihydroorotate dehydrogenase (K i = 2.7 μ M) and de novo pyrimidine synthesis in T-cells; blocks lymphocyte cell cycle progression and proliferation. A77 1726 also inhibits anti-CD3/CD28-induced cytokine production in PBMC cells (IC 50 = 21-27 μ g/ml). In vivo reduces inflammation in several animal models of autoimmune disease, arthritis, asthma and graft rejection.

Leflunomide Preparation Products And Raw materials

Raw materials

Preparation Products

Leflunomide Suppliers

Global( 260)Suppliers
Supplier Tel Fax Email Country ProdList Advantage
Shenzhen Sendi Biotechnology Co.Ltd.
0755-23311925 18102838259
0755-23311925 CHINA 3218 55
Henan DaKen Chemical CO.,LTD.
+86-371-55531817 CHINA 22144 58
Hi-Tech Chemistry Corp
0519-86626038 CHINA 811 58
Henan Tianfu Chemical Co.,Ltd.
0371-55170693 CHINA 20803 55
Mainchem Co., Ltd.
+86-0592-6210733 CHINA 32765 55
020-81716319 CHINA 2549 55
career henan chemical co
+86-371-86658258 CHINA 10012 58
Wuhan DKY Technology Co.,Ltd. 027-81302488 18007166089
027-81302088; China 1965 58
J & K SCIENTIFIC LTD. 400-666-7788 +86-10-82848833
+86-10-82849933; China 96815 76
INTATRADE GmbH +49 3493/605464
+49 3493/605470 Germany 3587 66

View Lastest Price from Leflunomide manufacturers

Image Release date Product Price Min. Order Purity Supply Ability Manufacturer
2018-08-20 Leflunomide
US $7.00 / KG 1KG 99% 100KG

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