4''-(Pentyloxy)-[1,1':4',1''-terphenyl]-4-carboxylic acid

CAS 158938-08-0

4''-(Pentyloxy)-[1,1':4',1''-terphenyl]-4-carboxylic acid (CAS 158938-08-0) has a chemical story that connects molecular identity with practical chemistry. 4''-(Pentyloxy)-[1,1':4',1''-terphenyl]-4-carboxylic acid is a rigid aromatic acid with a specific pharmaceutical-process role. Patent and synthesis literature identify it as the lipophilic terphenyl side-chain intermediate used to manufacture the semisynthetic echinocandin antifungal anidulafungin. Published routes construct the extended terphenyl system by carbon-carbon cross-coupling, illustrating modular pharmaceutical synthesis. The pentoxy substituent contributes hydrophobic character, while the terminal carboxylic acid supplies the coupling handle. It is an engineered intermediate that becomes part of a much larger antifungal molecule, not an antifungal drug by itself.

The exact CAS identity matters because related salts, stereoisomers, intermediates and finished medicines can play very different roles even when their names look closely related.

Its story also shows why synthesis and analytical control belong together: chemists must create the intended structure, distinguish it from process-related species and verify the form actually being handled.