Fimasartan
[CAS 247257-48-3]

Identification

• Classification: API >> Circulatory system medication >> Antihypertensive drug
• Name: Fimasartan
• Synonyms: 2-Butyl-5-dimethylaminothiocarbonylmethyl-6-methyl-3-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]pyrimidin-4(3H)-one
• Molecular Formula: C₂₇H₃₁N₇OS
• Molecular Weight: 501.65
• CAS Registry Number: 247257-48-3
• SMILES: CCCCC1=NC(=C(C(=O)N1CC2=CC=C(C=C2)C3=CC=CC=C3C4=NNN=N4)CC(=S)N(C)C)C

Properties

• Density: 1.3±0.1 g/cm³ Calc.^*
• Boiling point: 693.0±65.0 °C 760 mmHg (Calc.)^*
• Flash point: 372.9±34.3 °C (Calc.)^*
• Solubility: DMSO: 49mg/mL (Expl.)
• Index of refraction: 1.658 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS02;GHS07 Danger
• Risk Statements: H228-H315-H319
• Safety Statements: P240-P210-P241-P264-P280-P302+P352-P370+P378-P337+P313-P305+P351+P338-P362+P364-P332+P313
• Transport Information: UN 1325

chemBlink Chemical Story

Fimasartan, CAS 247257-48-3, is a nonpeptide angiotensin II receptor blocker developed by Boryung Pharmaceutical in South Korea. It was known during development as BR-A-657. Published medicinal-chemistry work describes its discovery from a series of pyrimidin-4(3H)-one derivatives designed as losartan analogues and identifies fimasartan as a highly potent, orally active antagonist selective for the angiotensin II AT1 receptor.

The renin-angiotensin system regulates vascular tone and blood pressure. Angiotensin II binding to AT1 receptors promotes vasoconstriction and other responses that raise blood pressure. Fimasartan blocks this receptor, preventing angiotensin II from producing its normal AT1-mediated effects. This places it in the same pharmacological family as losartan, valsartan and other angiotensin receptor blockers, although its detailed molecular structure and pharmacokinetic profile are distinct.

The discovery program is a useful example of analogue-based drug design. Researchers retained the general pharmacophore concept established by earlier angiotensin receptor antagonists but explored pyrimidinone derivatives and different substituents. The compound reported as 12a/BR-A-657 combined very high AT1 binding affinity and functional antagonism with oral activity in animal models. That balance, rather than receptor affinity alone, supported its development as fimasartan.

Fimasartan was first approved in South Korea in 2010 for hypertension. Clinical development evaluated it alone and in combinations, including with hydrochlorothiazide. PubChem and FDA substance records identify the free compound as C27H31N7OS; marketed pharmaceutical forms may use a salt, so the CAS identity of the free molecule should not automatically be applied to every drug-product solid form.

Its chemical story illustrates the evolution of a mature drug class. Once a validated biological target exists, innovation can proceed by redesigning the molecular scaffold to improve potency, oral exposure and practical pharmaceutical properties while preserving the established mechanism. Fimasartan is therefore both an AT1 antagonist and an example of regional pharmaceutical discovery producing a new member of a globally important antihypertensive class.

References:
1. PubChem, Fimasartan, CID 9870652, CAS 247257-48-3.
2. Kim TW et al. Bioorg Med Chem Lett. 2012;22:1649-1654. DOI: 10.1016/j.bmcl.2011.12.116.
3. Fimasartan. Am J Cardiovasc Drugs. 2011;11:249-252. PMID: 21740078.
4. U.S. FDA GSRS, Fimasartan, UNII P58222188P.

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