3-Cyanopyrazole
[CAS# 36650-74-5]

Identification

• Classification: Organic raw materials >> Heterocyclic compound
• Name: 3-Cyanopyrazole
• Synonyms: 1H-Pyrazole-3-carbonitrile; 5-Cyanopyrazole; Pyrazole-3-carbonitrile
• Molecular Formula: C₄H₃N₃
• Molecular Weight: 93.09
• CAS Registry Number: 36650-74-5
• EC Number: 675-771-5
• SMILES: C1=C(NN=C1)C#N

Properties

• Density: 1.3±0.1 g/cm³ Calc.^*
• Boiling point: 317.4±15.0 °C 760 mmHg (Calc.)^*
• Flash point: 114.0±5.6 °C (Calc.)^*
• Index of refraction: 1.551 (Calc.)^*

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

Safety Data

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

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2	H319
Acute toxicity	Acute Tox.	4	H332
Eye irritation	Eye Irrit.	2A	H319
Acute toxicity	Acute Tox.	4	H312
Acute toxicity	Acute Tox.	4	H302

Discovery and Applications

3‑Cyanopyrazole (also called 1H‑pyrazole‑3‑carbonitrile) is a small heterocyclic nitrile with the molecular formula C₄H₃N₃ and CAS number 36650‑74‑5. The pyrazole ring includes two adjacent nitrogen atoms, and the cyano (–C≡N) group is attached at the 3‑position, making this compound a useful intermediate in heterocyclic and medicinal chemistry.

This molecule has been used as a building block in the synthesis of more complex pyrazole derivatives. Because of its cyano group, it is amenable to a variety of chemical transformations: it can be converted into amidines, amides, or other nitrogen‑containing functional groups, or participate in cycloaddition reactions. The pyrazole core itself is a privileged scaffold in drug discovery, and addition of a nitrile moiety increases its utility, enabling the design of molecules that can serve as enzyme inhibitors, ligands, or biologically active heterocycles.

In synthetic chemistry practice, 3‑cyano‑pyrazole can be used in palladium‑catalyzed cross‑couplings, in addition to nucleophilic attacks on the nitrile to build up molecular complexity. Its relative stability and manageable reactivity make it a good substrate for multistep organic synthesis. Because the molecule is fairly simple and commercially available in high purity, it is commonly employed in medicinal chemistry as a starting point for hit‑to‑lead optimization.

As a solid compound, 3‑cyanopyrazole requires standard laboratory precautions: it should be stored in a dry environment to avoid moisture uptake, and reactions involving the nitrile group are typically performed in aprotic solvents under inert atmosphere to prevent side-reactions. There is limited data on pharmacological properties for 3‑cyano‑pyrazole itself — most applications stem from its use as a synthetic building block rather than as a final bioactive agent.

Because of its versatility, 3‑cyanopyrazole remains a valuable intermediate in the synthesis of nitrogen-rich heterocycles, offering a bridge to more elaborated pyrazole-based frameworks in materials science, medicinal chemistry, and organic synthesis.

References

Synthesis and Antimicrobial Activity of Substituted Amino-1H-Pyrazoles (2025) Pharmaceutical Chemistry Journal DOI: 10.1007/s11094-025-03358-4

Reactions of spirocyclopropane-containing 1- and 2-pyrazolines with electrophilic reagents (2000) Russian Chemical Bulletin 49 3 601–607 DOI: 10.1007/bf02494777

Synthesis and Pharmacological Activities of Pyrazole and Oxadiazole Derivatives: a Review (2023) Russian Journal of Organic Chemistry 59 5 732–752 DOI: 10.1134/s1070428023050160