The Leflunomide, with the CAS registry number 75706-12-6, is also known as 4-Isoxazolecarboxamide, 5-methyl-N-(4-(trifluoromethyl)phenyl)-; 5-Methylisoxazole-4-carboxylic acid (4-trifluoromethyl)anilide; Arava. It belongs to the product categories of Active Pharmaceutical Ingredients; API; Osteoarthritis and Rheumatoid Arthritis; Inhibitors; Intermediates & Fine Chemicals; Pharmaceuticals; Cytokine signaling; Aromatics; Heterocycles; An immunosuppressive agent. This chemical's molecular formula is C₁₂H₉F₃N₂O₂ and molecular weight is 270.21. What's more, its systematic name is 5-Methyl-N-[4-(trifluoromethyl)phenyl]-1,2-oxazole-4-carboxamide. In addition, Leflunomide(CAS 75706-12-6) is off white crystalline solid which should be sealed in the container and stored in the cool and dry place.

Physical properties about Leflunomide are: (1)ACD/LogP:  2.287; (2)# of Rule of 5 Violations:  0; (3)ACD/LogD (pH 5.5):  2.29; (4)ACD/LogD (pH 7.4):  2.29; (5)ACD/BCF (pH 5.5):  32.22; (6)ACD/BCF (pH 7.4):  32.22; (7)ACD/KOC (pH 5.5):  417.95; (8)ACD/KOC (pH 7.4):  417.92; (9)#H bond acceptors:  4; (10)#H bond donors:  1; (11)#Freely Rotating Bonds:  2; (12)Polar Surface Area:  55.13 Å²; (13)Index of Refraction:  1.541; (14)Molar Refractivity:  61.024 cm³; (15)Molar Volume:  194.108 cm³; (16)Polarizability:  24.192×10^-24 cm³; (17)Surface Tension:  40.5660018920898 dyne/cm; (18)Density:  1.392 g/cm³; (19)Flash Point:  128.771 °C; (20)Enthalpy of Vaporization:  52.861 kJ/mol; (21)Boiling Point:  289.311 °C at 760 mmHg; (22)Vapour Pressure:  0.0020000000949949 mmHg at 25°C.

Preparation of Leflunomide(CAS 75706-12-6): It can be produced by 5-methyl-isoxazole-4-carbonyl chloride and 4-trifluoromethyl-aniline.  This reaction needs solvent diethyl ether at ambient temperature. The yield is 93%.

Uses of Leflunomide: It is a DMARD which is used in active moderate to severe rheumatoid arthritis and psoriatic arthritis. It is also an immunomodulatory drug inhibiting dihydroorotate dehydrogenase. It can relieve symptoms of rheumatoid arthritis and psoriatic arthritis. What's more, Leflunomide (CAS 75706-12-6) can be used to produce other chemicals. For example, it can react with dimethoxymethyl-dimethyl-amine to get dimethoxymethyl-dimethyl-amine. This reaction needs solvent dioxane. The yield is 60%.

When you are using this chemical, please be cautious about it as the following: Leflunomide (CAS 75706-12-6) is harmful if swallowed. And it is irritating to eyes, respiratory system and skin. In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. So people should wear suitable protective clothing when contact it.

You can still convert the following datas of Leflunomide (CAS 75706-12-6) into molecular structure:
(1) SMILES:O=C(Nc1ccc(cc1)C(F)(F)F)c2c(onc2)C
(2) Std. InChI:InChI=1S/C12H9F3N2O2/c1-7-10(6-16-19-7)11(18)17-9-4-2-8(3-5-9)12(13,14)15/h2-6H,1H3,(H,17,18)
(3) Std. InChIKey:VHOGYURTWQBHIL-UHFFFAOYSA-N

The following are the toxicity data of Leflunomide (CAS 75706-12-6) which has been tested.