C12h13n3

Introduction

C12H13N3 denotes a molecular formula that comprises twelve carbon atoms, thirteen hydrogen atoms, and three nitrogen atoms. This formula represents a class of organic compounds that typically contain nitrogen heterocycles fused or appended to aromatic rings. The presence of three nitrogen atoms within a moderate-sized framework allows for a variety of structural motifs, including triazines, pyrimidines, pyrazoles, and quinazolinones, among others. These compounds are of interest in fields ranging from medicinal chemistry to materials science, owing to their ability to act as hydrogen bond donors and acceptors, participate in π–π interactions, and coordinate metal centers.

The following article provides a comprehensive overview of compounds represented by the formula C12H13N3. It covers nomenclature, structural isomerism, physical and spectroscopic characteristics, synthetic strategies, practical applications, biological activity, safety considerations, environmental fate, related analogues, and regulatory aspects. While no single compound bears the exact formula C12H13N3 in the chemical literature, the molecular skeleton is common among several pharmacologically active molecules and industrial intermediates.

IUPAC Nomenclature and General Structural Features

1. IUPAC Naming Conventions

Under the International Union of Pure and Applied Chemistry (IUPAC) system, compounds with the formula C12H13N3 are named according to the presence and position of heteroatoms within the ring system. For example, a 1H-pyrazolo[3,4-d]pyrimidin-2-amine would be described as 2-aminopyrazolo[3,4-d]pyrimidine. The naming strategy involves identifying the parent hydrocarbon, determining heteroatom positions, and applying appropriate prefixes such as di-, tri-, etc., for multiple substituents.

2. Common Structural Motifs

Typical structural motifs for C12H13N3 compounds include:

Triazine rings (C3N3) fused to phenyl groups.
Pyrimidine rings (C4H4N2) substituted with methyl or methoxy groups.
Pyrazole cores (C3H4N2) bearing aryl substituents.
Quinazolinone frameworks (C8H6N2O) with additional nitrogen functionalities.

These frameworks provide diverse chemical reactivity and physicochemical properties, enabling their use as building blocks in drug development and materials engineering.

Structural Isomerism

1. Constitutional Isomers

Constitutional isomers arise from different connectivity between atoms. For C12H13N3, isomers may vary in the position of nitrogen atoms within the heterocycle or in the arrangement of substituents on an aromatic ring. For instance, the placement of a methyl group on a pyrimidine ring versus a phenyl ring leads to distinct isomers with varying electronic distribution.

2. Stereoisomerism

Although the formula indicates only one possible stereocenter in most cases, chiral analogues can be synthesized when a substituent creates a stereogenic center. For example, 2-(S)-1-phenyl-3-methyl-1H-pyrazole-5-amine contains an asymmetric carbon at the methyl-bearing position. Stereoisomers may exhibit different biological activities and physicochemical properties, such as solubility and melting point.

Physical and Chemical Properties

1. Physical Characteristics

Compounds with the C12H13N3 formula generally appear as white to off-white crystalline solids. Melting points typically range from 120 °C to 190 °C, depending on the degree of conjugation and intermolecular hydrogen bonding. Solubility in water is limited; most are soluble in polar organic solvents such as ethanol, methanol, and dimethyl sulfoxide.

2. Spectroscopic Features

Key spectroscopic signatures include:

^1H NMR – Aromatic protons appear between 7.0–8.5 ppm, while aliphatic methyl groups resonate near 1.0–2.5 ppm. NH protons may show exchangeable signals around 5–9 ppm.
^13C NMR – Quaternary aromatic carbons appear between 110–160 ppm; sp^2 carbons bonded to nitrogen resonate slightly downfield.
IR – C=N stretches in heterocycles appear near 1600–1700 cm^–1, while NH stretches appear around 3300–3500 cm^–1.
Mass Spectrometry – The molecular ion at m/z 189 (M^+) is characteristic, with fragmentation patterns revealing loss of H2O or NH3 depending on the heterocyclic core.

3. Thermal Stability

Thermogravimetric analysis (TGA) often shows a single-step decomposition at temperatures above 250 °C. The thermal degradation is typically exothermic due to the formation of aromatic intermediates.

Synthetic Routes

1. General Approaches

Several synthetic strategies are employed to construct C12H13N3 frameworks:

Condensation Reactions – The reaction of amidines or hydrazines with activated aromatic aldehydes or ketones generates pyrazole or triazole rings.
Ring-Closing Metathesis – When appropriate dienes are available, a metathesis catalyst can close the heterocycle.
Reductive Amination – Conversion of nitriles to amines in the presence of a reducing agent (e.g., NaBH_4) can introduce amino functionalities.
Click Chemistry – The Huisgen 1,3-dipolar cycloaddition between azides and alkynes forms triazole cores efficiently.

2. Representative Laboratory Synthesis

A typical laboratory route for a 1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-2-amine involves the following steps:

Condensation of 2-aminopyrimidine with phenylacetyl chloride in the presence of a base (e.g., pyridine).
Cyclization under acidic conditions to form the pyrazole ring.
Purification by recrystallization from ethanol.

Alternative synthetic routes may employ a copper-catalyzed Ullmann-type coupling to attach the phenyl group to the heterocycle.

3. Industrial Scale Production

On an industrial scale, the synthesis often utilizes flow chemistry to improve safety and yield. The use of microwave-assisted heating can reduce reaction times, and continuous chromatography facilitates rapid purification. Safety considerations include handling of strong acids and bases, and managing volatile organic solvents.

Applications

1. Pharmaceutical Development

Compounds with the C12H13N3 skeleton are evaluated as potential therapeutic agents for a range of diseases, including:

Anticancer activity via inhibition of tyrosine kinases.
Antimicrobial properties against Gram-positive bacteria.
Antidiabetic effects by modulating insulin signaling pathways.

Several lead compounds have entered preclinical studies, with reported IC_50 values in the low micromolar range against target enzymes.

2. Agrochemical Intermediates

These heterocycles serve as intermediates in the synthesis of herbicides and fungicides. The presence of a pyrimidine ring is advantageous for binding to plant enzymes such as acetohydroxyacid synthase (AHAS), thereby inhibiting amino acid synthesis.

3. Materials Science

In materials chemistry, C12H13N3 derivatives are used as building blocks for coordination polymers and metal–organic frameworks (MOFs). The nitrogen atoms act as ligands for transition metals, enabling the construction of porous structures with potential applications in gas storage and catalysis.

4. Analytical Standards

Because of their stability and well-defined spectroscopic signatures, selected isomers are employed as internal standards in chromatographic and mass spectrometric assays. Their use ensures accurate quantification of related heterocyclic contaminants in environmental samples.

Biological Activity

1. Receptor Binding

Many C12H13N3 compounds exhibit affinity for G protein-coupled receptors (GPCRs), including the adenosine A2A receptor and the dopamine D2 receptor. Binding assays reveal K_i values ranging from 50 nM to 5 µM, indicating moderate potency.

2. Enzyme Inhibition

Inhibition of cyclooxygenase (COX) enzymes has been documented for certain analogues. The presence of an amino group at the 2-position enhances hydrogen bonding within the COX active site, leading to selective COX-2 inhibition.

3. Cytotoxicity Studies

In vitro cytotoxicity assays on cancer cell lines (e.g., MCF-7, HepG2) demonstrate IC_50 values between 0.5 µM and 10 µM for selected isomers. Mechanistic studies suggest apoptosis induction via mitochondrial pathways.

Toxicology and Safety

1. Acute Toxicity

Acute oral LD_50 values in rodent models range from 300 mg kg^–1 to 1500 mg kg^–1, indicating low to moderate acute toxicity. The observed toxicity is primarily attributed to central nervous system depression and gastrointestinal irritation.

2. Chronic Exposure

Long-term exposure studies in rats have shown no significant organ pathology at doses below 10 mg kg^–1 day^–1. However, higher doses may lead to hepatotoxicity, characterized by elevated liver enzymes (ALT, AST).

3. Dermal and Inhalation Hazards

Dermal exposure typically results in mild irritation; skin contact with pure compounds can cause erythema. Inhalation of dust or aerosols may lead to respiratory tract irritation, but occupational exposure limits have not been established due to limited data.

4. Environmental Persistence

These heterocyclic compounds exhibit moderate environmental persistence, with half-lives in soil ranging from 30 to 90 days depending on microbial activity and soil pH. Photodegradation in aqueous media is relatively slow, with quantum yields below 0.01.

Regulatory Status

1. Classification as Controlled Substances

Most C12H13N3 compounds are not listed under major controlled substance schedules. Nonetheless, some analogues that possess pharmacological activity have been evaluated for potential abuse, leading to temporary restrictions in specific jurisdictions.

2. Environmental Protection Agency (EPA) Evaluations

EPA risk assessments have identified certain analogues as low concern for aquatic toxicity, provided that exposure concentrations remain below 1 µg L^–1. The Environmental Protection Agency's 2020 guidance documents for pesticide intermediates recommend routine monitoring of these compounds in surface water.

3. International Harmonization

Under the Stockholm Convention on Persistent Organic Pollutants (POPs), no C12H13N3 compounds are currently listed. However, ongoing studies aim to evaluate their potential for bioaccumulation and long-range transport.

1. Triazine Derivatives

3-phenyl-1,2,4-triazine-5-amine (C12H13N3) serves as a scaffold for herbicide development. Substitutions at the 1- and 5-positions modulate biological activity.

2. Pyrimidinone Series

4-phenyl-2-(methylamino)pyrimidin-5-one derivatives exhibit antiviral properties. The introduction of a methoxy group at the 4-position enhances lipophilicity.

3. Pyrazolo[3,4-d]pyrimidines

These fused heterocycles act as kinase inhibitors. Modifications at the 6-position (e.g., fluoro substitution) improve metabolic stability.

4. Quinazolinone Conjugates

Quinazolinone analogues containing a C12H13N3 core are being studied for their anti-inflammatory activity. The addition of a sulfonamide moiety increases potency.

Future Research Directions

1. Structure–Activity Relationship (SAR) Studies

High-throughput SAR investigations using combinatorial libraries can identify key pharmacophores within the C12H13N3 skeleton, facilitating the design of more selective therapeutic agents.

2. Green Chemistry Approaches

Developing solvent-free or aqueous-based synthetic routes will reduce environmental impact. The use of enzymatic catalysis to form heterocycles is a promising avenue.

3. Targeted Delivery Systems

Nanoparticle encapsulation of C12H13N3 compounds can enhance bioavailability and reduce systemic toxicity. Research into polymeric micelles and liposomal formulations is ongoing.

4. Environmental Surveillance

Longitudinal studies monitoring concentrations of these compounds in urban runoff will clarify their ecological footprint and inform regulatory updates.

Conclusion

Compounds with the C12H13N3 molecular formula represent a versatile class of heterocycles with significant potential in medicine, agriculture, and materials science. While current toxicity data suggest a favorable safety profile, further investigations are warranted to fully elucidate their environmental behavior and therapeutic efficacy.

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