1H-pyrazol-3-amine

1H-Pyrazol-3-amine: Overview and chemical identifiers

1H-Pyrazol-3-amine is a pyrazole heterocycle bearing an exocyclic amino group. CAS 1820-80-0 identifies the unsubstituted aminopyrazole described here. Its ring nitrogens and amino group make it a useful building block for pyrazole functionalization and fused nitrogen heterocycles.

Names, synonyms and CAS 1820-80-0

3-Aminopyrazole and 1H-pyrazol-3-amine are established names. The names 1H-pyrazol-5-amine and 3(5)-aminopyrazole are also used because proton transfer between the ring nitrogen atoms interconverts annular tautomers and changes the apparent numbering. These labels describe the same tautomeric compound system, not different positional isomers. The 3-aminopyrazole CAS number is 1820-80-0; the name should also be checked against the formula and structure to exclude substituted aminopyrazoles.

Molecular structure and chemical properties

The molecular formula is C3H5N3, and the molecular weight is 83.09 g/mol. The structure can be represented by the SMILES notation Nc1cc[nH]n1. Its standard InChI is InChI=1S/C3H5N3/c4-3-1-2-5-6-3/h1-2H,(H3,4,5,6), and the InChIKey is JVVRJMXHNUAPHW-UHFFFAOYSA-N. Because tautomerism can produce different drawings and names, identity should be confirmed from the full set of identifiers. Physical form, storage, and handling guidance should be taken from the SDS for the selected product.

Synthesis and research applications

Published 1H-pyrazol-3-amine synthesis routes include reactions of hydrazine with activated unsaturated nitriles. For the unsubstituted compound, α-chloroacrylonitrile has been used in a sequence involving addition, ring closure, and dehydrogenation; 2,3-dichloropropionitrile has also served as a precursor. Reactions of hydrazines with β-ketonitriles or related nitrile-containing substrates are established 3-aminopyrazole synthesis strategies, especially for substituted derivatives. The precursor and conditions determine the final substitution pattern.

In research synthesis, 3-aminopyrazole acts as a binucleophilic building block. Its amino group and a ring nitrogen can react with suitable 1,3-bis-electrophiles, including selected 1,3-dicarbonyl compounds and activated unsaturated carbonyl derivatives, to form pyrazolo[1,5-a]pyrimidine frameworks. Functionalization at the amino group or pyrazole ring can provide other derivatives.

Sourcing and supplier selection on ChemSpace

ChemSpace is a marketplace presenting offers from independent suppliers rather than a manufacturer of 1H-pyrazol-3-amine. Researchers evaluating CAS 1820-80-0 should confirm that an offer corresponds to the neutral, unsubstituted compound. Before ordering, review the current offer record, CoA, and SDS for identity, analytical data, and handling information. Selection should follow the documented requirements of the intended laboratory workflow.