Leflunomide , ≥98% , 75706-12-6

Synonym(s):
5-Methyl-N-[4-(trifluoromethyl) phenyl]-isoxazole-4-carboxamide;5-Methylisoxazole-4-(4-trifluoromethyl)carboxanilide;Leflunomide

CAS NO.：75706-12-6

Empirical Formula: C12H9F3N2O2

Molecular Weight: 270.21

MDL number: MFCD00867593

EINECS: 616-254-6

PRODUCT Properties

• Melting point: 166.5 °C
• Boiling point: 289.3±40.0 °C(Predicted)
• Density: 1.392±0.06 g/cm3(Predicted)
• storage temp.: 2-8°C
• solubility: Practically insoluble in water, freely soluble in methanol, sparingly soluble in methylene chloride.
• pka: 10.8(at 25℃)
• form: Solid
• color: White
• Merck: 14,5432
• Stability: Stable for 2 years from date of purchase as supplied. Solutions in DMSO or ethanol may be stored at -20° for up to 1 month.
• InChIKey: VHOGYURTWQBHIL-UHFFFAOYSA-N

Description and Uses

Leflunomide is an orally-available disease-modifying antirheumatic drug and was launched as Arava in the US for the treatment of rheumatoid arthritis (RA) ; it is the first and only drug to be indicated to slow down structural joint damage of RA, so addressing an unmet medical need.
Leflunomide is prepared in 3 steps from the appropriate acetoacetic anilide using a nitrile oxide- enamine cycloaddition reaction to assemble the isoxazole ring. Leflunomide is a prodrug, being extensively metabolized in vivo into the corresponding 2-cyano-3-hydroxy-2-butenamide resulting from fragmentation of the isoxazole ring. This cyanoenol is actually the active metabolite and several experiments in animals have demonstrated that after oral administration, substantial and sustained levels of this metabolite were delivered to the systemic circulation.
In vitro, Leflunomide’s active metabolite inhibits dihydroorotate dehydrogenase, an enzyme involved in the biosynthesis of pyrimidine nucleotides, probably accounting for its immunosuppressive effect in vivo. Other mechanisms of action such as inhibition of tyrosine kinase and inhibition of responsiveness to interleukin-2 have been proposed. In diverse models of autoimmune or allergic diseases, Leflunornide showed efficacy both prophylactically and therapeutically.

vasodilator

Safety

• Symbol(GHS): GHS06
• Signal word: Danger
• Hazard statements: H301-H315-H319-H335
• Precautionary statements: P261-P264-P270-P301+P310-P302+P352-P305+P351+P338
• 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
• HS Code: 2934990002