(alphaR,gammaS)-gamma-[(3-Carboxy-1-oxopropyl)amino]-alpha-methyl-[1,1'-biphenyl]-4-pentanoic acid 4-ethyl ester calcium salt (2:1)
[CAS 1369773-39-6]

Identification

• Classification: API >> Other chemicals
• Name: (alphaR,gammaS)-gamma-[(3-Carboxy-1-oxopropyl)amino]-alpha-methyl-[1,1'-biphenyl]-4-pentanoic acid 4-ethyl ester calcium salt (2:1)
• Synonyms: AHU-377 hemicalcium salt
• Molecular Formula: 2(C₂₄H₂₉NO₅).Ca
• Molecular Weight: 863.06
• CAS Registry Number: 1369773-39-6
• EC Number: 810-306-3
• SMILES: CCOC(=O)[C@H](C)C[C@@H](CC1=CC=C(C=C1)C2=CC=CC=C2)NC(=O)CCC(=O)[O-].CCOC(=O)[C@H](C)C[C@@H](CC1=CC=C(C=C1)C2=CC=CC=C2)NC(=O)CCC(=O)[O-].[Ca+2]

Properties

• Solubility: Soluble DMSO: 100 mM, ethanol :20 mM (Expl.)

Safety Data

• Hazard Symbols: GHS06;GHS09 Danger
• Risk Statements: H301-H400
• Safety Statements: P273-P301+P310+P330

chemBlink Chemical Story

(alphaR,gammaS)-gamma-[(3-carboxy-1-oxopropyl)amino]-alpha-methyl-[1,1′-biphenyl]-4-pentanoic acid 4-ethyl ester calcium salt (2:1) is a complex, stereochemically defined biphenyl-containing amino acid derivative present as a calcium salt in a 2:1 stoichiometric ratio. The structure combines aromatic biphenyl hydrophobic domains with multiple carboxylic acid functions, an amide linkage, and an ester-protected acid, resulting in a multifunctional amphiphilic organic framework.

The central backbone of the molecule is a substituted pentanoic acid chain bearing both stereochemical centers and functionalized side groups. The designations (alphaR, gammaS) indicate two defined chiral centers, which establish a specific three-dimensional arrangement of substituents along the aliphatic chain. These stereochemical constraints influence the spatial orientation of the functional groups and contribute to the overall conformational preference of the molecule.

At the gamma position of the chain is an amide substituent described as a [(3-carboxy-1-oxopropyl)amino] group. This moiety contains a secondary amide linkage formed between an amino group and a substituted propionic acid fragment. The presence of both a carboxyl group and a ketone-like carbonyl within this side chain introduces strong polarity and multiple hydrogen-bonding sites. The amide bond itself exhibits resonance stabilization, giving partial double-bond character and restricting rotation around the C–N bond.

At the alpha position of the pentanoic backbone is a methyl substituent, which contributes steric bulk and defines one of the stereogenic centers. This substitution increases hydrophobicity locally and affects the overall folding and spatial arrangement of the molecule.

A key structural feature is the [1,1′-biphenyl]-4-yl moiety attached to the main chain. Biphenyl consists of two connected phenyl rings that can adopt non-coplanar conformations due to steric repulsion between ortho hydrogen atoms. This biphenyl unit contributes significant hydrophobic surface area and aromatic character. The para substitution at the 4-position provides a defined point of attachment to the aliphatic backbone, while the biphenyl system introduces rigidity and π-electron-rich domains capable of aromatic stacking interactions.

The molecule also contains an ester functionality at the 4-position of the pentanoic acid chain, specifically an ethyl ester. Ester groups are characterized by a carbonyl bonded to an alkoxy substituent, providing moderate polarity and acting as hydrogen-bond acceptors. Esterification reduces the acidity of the corresponding carboxylic acid and modifies solubility and lipophilicity.

The overall compound is present as a calcium salt in a 2:1 ratio, meaning two organic anionic units are associated with one calcium cation. Calcium ions are divalent and coordinate primarily through electrostatic interactions with carboxylate groups. In solution or solid-state structures, calcium can stabilize carboxylate anions through ionic coordination, influencing crystallinity, solubility, and aggregation behavior.

From a structural perspective, the molecule combines rigid aromatic systems (biphenyl) with flexible aliphatic chains and multiple polar functional groups. The amide and carboxylate groups introduce strong polarity and hydrogen-bonding capability, while the biphenyl and aliphatic regions contribute hydrophobic character. This creates a strongly amphiphilic molecule with distinct polar and nonpolar domains.

Chemically, the most reactive functional groups include the ester linkage, which can undergo hydrolysis under acidic or basic conditions, and the amide-containing side chain, which is generally more stable but can be cleaved under strong hydrolytic conditions. The carboxylate groups interact strongly with metal ions such as calcium, forming coordination complexes that influence physical form and stability.

The biphenyl aromatic system is chemically stable under typical conditions but may participate in π–π interactions in condensed phases. The stereochemistry at both chiral centers plays an important role in defining the molecule’s three-dimensional conformation and potential interaction behavior.

Without specific literature confirming biological or functional roles for this exact compound, no application claims can be made. Based solely on structural analysis, it is best described as a stereochemically defined biphenyl-substituted amino acid derivative containing multiple carboxyl and amide functionalities, present as a calcium coordination salt that stabilizes the carboxylate groups and contributes to its solid-state organization.

References

1976. Drug treatment of insomnia in old age. Psychopharmacology bulletin.