1-(Cyclopropylcarbonyl)piperazine hydrochloride
[CAS# 1021298-67-8]

Identification

• Classification: Pharmaceutical intermediate >> Heterocyclic compound intermediate >> Piperazine
• Name: 1-(Cyclopropylcarbonyl)piperazine hydrochloride
• Synonyms: (Cyclopropyl)(piperazin-1-yl)methanone hydrochloride
• Molecular Formula: C₈H₁₄N₂O.HCl
• Molecular Weight: 190.67
• CAS Registry Number: 1021298-67-8
• EC Number: 810-996-6
• SMILES: C1CC1C(=O)N2CCNCC2.Cl

Properties

• Melting point: 174 - 176 $degree$C (Expl.)

Safety Data

• Hazard Symbols: GHS02;GHS07 DangerGHS02
• Risk Statements: H228-H302-H315-H317-H319
• Safety Statements: P210-P240-P241-P261-P264-P264+P265-P270-P272-P280-P301+P317-P302+P352-P305+P351+P338-P321-P330-P332+P317-P333+P317-P337+P317-P362+P364-P370+P378-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Acute toxicity	Acute Tox.	4	H302
Flammable solids	Flam. Sol.	2	H228
Skin sensitization	Skin Sens.	1	H317
Specific target organ toxicity - single exposure	STOT SE	3	H335

Discovery and Applications

1-(Cyclopropylcarbonyl)piperazine hydrochloride is an organic compound that belongs to the class of N-substituted piperazine derivatives, which have been extensively studied in medicinal and synthetic chemistry. Piperazine is a heterocyclic diamine that has been known since the late nineteenth century, and derivatives of piperazine were explored in the twentieth century for their diverse pharmacological properties. N-acylation of piperazine, such as with a cyclopropylcarbonyl group, provides molecules with defined structural and electronic characteristics that can be useful for both chemical synthesis and drug development. The compound is typically prepared by reacting piperazine with cyclopropylcarbonyl chloride under controlled conditions to form the corresponding N-cyclopropylcarbonyl derivative. The hydrochloride salt is often isolated to enhance stability, improve solubility in water, and facilitate handling. The cyclopropyl group introduces a strained three-membered ring that can influence the molecule’s chemical reactivity and steric profile. This structural feature has been exploited in pharmaceutical research because cyclopropyl-substituted amides can alter binding interactions, metabolic stability, and pharmacokinetic properties compared with non-cyclopropyl analogs. 1-(Cyclopropylcarbonyl)piperazine hydrochloride and related N-acyl piperazine compounds have been studied as intermediates in the synthesis of pharmacologically active agents. Piperazine derivatives have served as scaffolds in the development of drugs targeting the central nervous system, including antipsychotic, anxiolytic, and antidepressant agents. The introduction of an acyl group at the nitrogen atom modifies the lipophilicity, hydrogen bonding capability, and steric environment of the piperazine ring, allowing medicinal chemists to fine-tune biological activity in drug discovery programs. In addition to medicinal applications, N-substituted piperazines are valuable building blocks in synthetic organic chemistry. The secondary amine of piperazine can undergo further chemical transformations, including alkylation, acylation, and cyclization reactions. By using a hydrochloride salt, chemists can control reaction conditions and improve yield and purity during multistep synthetic sequences. Compounds like 1-(cyclopropylcarbonyl)piperazine hydrochloride are particularly useful when designing molecules that require a defined piperazine core with a reactive acyl substituent. The cyclopropylcarbonyl group also influences the conformational properties of the molecule. Three-membered rings are strained, which can affect the orientation of the amide bond and the overall shape of the molecule. This feature has been leveraged in both medicinal chemistry and material science research to modify molecular interactions and optimize the fit of compounds within enzyme active sites or receptor binding pockets. Pharmacological and chemical studies on N-acyl piperazines demonstrated that such compounds exhibit predictable reactivity patterns and good chemical stability. They can be isolated, purified, and stored under standard laboratory conditions without significant decomposition. The use of hydrochloride salts further stabilizes the compound and enhances solubility in aqueous media, which is important for both chemical reactions and biological evaluation. Overall, 1-(cyclopropylcarbonyl)piperazine hydrochloride represents a well-characterized example of an N-substituted piperazine derivative. Its discovery and application illustrate the broader utility of acylated piperazines in synthetic chemistry, pharmaceutical research, and medicinal chemistry. The combination of a piperazine scaffold, an acyl substituent, and a cyclopropyl ring provides a versatile structural motif that has been extensively used in laboratory synthesis and drug development studies.

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