(1R,2S)-rel-2-(3,4-Difluorophenyl)cyclopropanamine hydrochloride
[CAS# 1156491-10-9]

Identification

• Classification: Chemical reagent >> Organic reagent >> Amine salt (ammonium salt)
• Name: (1R,2S)-rel-2-(3,4-Difluorophenyl)cyclopropanamine hydrochloride
• Synonyms: (1R,2S)-2-(3,4-difluorophenyl)cyclopropan-1-amine;hydrochloride
• Molecular Formula: C₉H₉F₂N.HCl
• Molecular Weight: 205.63
• CAS Registry Number: 1156491-10-9
• EC Number: 829-852-9
• SMILES: C1[C@H]([C@@H]1N)C2=CC(=C(C=C2)F)F.Cl

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P270-P271-P280-P301+P317-P302+P352-P304+P340-P305+P351+P338-P319-P321-P330-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin irritation	Skin Irrit.	2	H315
Acute toxicity	Acute Tox.	4	H302
Eye irritation	Eye Irrit.	2A	H319
Eye irritation	Eye Irrit.	2	H319

Discovery and Applications

(1R,2S)-rel-2-(3,4-Difluorophenyl)cyclopropanamine hydrochloride is a synthetic organic compound belonging to the class of substituted cyclopropanamines. Compounds of this type have attracted interest because the cyclopropane ring, with its rigid three-membered structure, can impose conformational constraints on attached substituents, thereby modulating receptor binding and pharmacological activity. The presence of a difluorophenyl substituent in this molecule further enhances its potential pharmacological profile, as fluorine atoms are known to influence lipophilicity, metabolic stability, and bioavailability.

The hydrochloride salt form is often prepared to increase solubility and stability, enabling better handling in both laboratory and clinical settings. This compound has been studied as a structural motif in the design of pharmacological agents that act on the central nervous system. In particular, derivatives of phenylcyclopropanamines have been explored for their potential as monoamine transporter inhibitors, a class of compounds relevant in the treatment of depression, anxiety, and related neuropsychiatric disorders. The difluoro substitution pattern on the phenyl ring is considered to fine-tune activity at different transporters, including those for dopamine, norepinephrine, and serotonin.

The discovery of this compound type arose from medicinal chemistry efforts aimed at finding alternatives to classical antidepressants and stimulants. The cyclopropane scaffold offers increased metabolic stability compared to open-chain analogues, and it has been used as a bioisostere to mimic more flexible structures while imparting resistance to enzymatic breakdown. The synthesis typically involves cyclopropanation reactions followed by amination and selective halogenation of the aromatic ring, with resolution to obtain stereoisomers of interest. The hydrochloride salt is obtained through protonation with hydrogen chloride.

In terms of applications, (1R,2S)-rel-2-(3,4-difluorophenyl)cyclopropanamine hydrochloride has been primarily investigated as a research compound rather than a widely used therapeutic drug. Its main role lies in serving as a tool in medicinal chemistry for structure–activity relationship studies. Such studies help in understanding how stereochemistry, fluorination, and ring constraints influence biological activity at neurotransmitter transporters and receptors. Compounds in this class may contribute to the development of novel antidepressants, psychostimulants, or other neuroactive agents.

Beyond neuropharmacology, the compound also represents an example of how chemical modification strategies such as cyclopropane incorporation and halogen substitution are applied to optimize drug candidates. By altering pharmacokinetics and pharmacodynamics in predictable ways, such modifications help researchers design compounds with improved therapeutic potential and fewer side effects.

Overall, (1R,2S)-rel-2-(3,4-difluorophenyl)cyclopropanamine hydrochloride exemplifies the interplay between synthetic organic chemistry and drug discovery. While not itself a marketed therapeutic, its discovery and use as a research agent have contributed to the broader effort of developing improved treatments for disorders involving monoaminergic dysfunction.