Introduction
C10H13N is a molecular formula that describes a family of organic compounds containing ten carbon atoms, thirteen hydrogen atoms, and a single nitrogen atom. The formula is consistent with a variety of structural frameworks, ranging from simple aliphatic amines to more complex heteroaromatic and bicyclic systems. Compounds with this composition are of interest in synthetic organic chemistry, medicinal chemistry, and materials science due to their diverse reactivity, biological activity, and functional properties.
Molecular Formula and General Properties
The stoichiometry C10H13N corresponds to a degree of unsaturation (double bond equivalents, DBE) of five. This suggests that any structural realization must contain at least five rings and/or double bonds. The nitrogen atom can be present as a secondary or tertiary amine, an imine, or an amide (if an additional oxygen is included in a different isomer). In the simplest scenario, the nitrogen acts as a nucleophilic center capable of forming σ‑bonds with carbon and hydrogen atoms. The presence of both aromatic and aliphatic components allows for a wide range of physicochemical behavior.
- Molecular weight: 149.23 g·mol–1 (for the most common isotopic composition).
- Typical melting point: 0–120 °C, depending on the degree of aromaticity and substitution pattern.
- Typical boiling point: 120–250 °C under atmospheric pressure.
- Solubility: Generally soluble in organic solvents such as ethanol, methanol, dichloromethane, and acetone. Limited solubility in water, enhanced by protonation of the nitrogen atom.
Structural Diversity
Compounds sharing the C10H13N formula can be classified into several structural categories based on the arrangement of rings, double bonds, and functional groups.
Aromatic Amines
These structures contain at least one phenyl ring. The nitrogen is typically attached to the aromatic system either directly (anilines) or via a methylene bridge (benzylamines). Examples include:
- 4‑Phenyl‑2‑methyl‑1,2‑diphenylmethane (though this example contains more carbons).
- 3‑Phenyl‑1‑piperidyl‑1‑methylamine (also known as N‑methyl‑3‑phenylpiperidine).
Saturated Cyclic Amines
These structures feature nitrogen within saturated ring systems such as piperidine, pyrrolidine, or azepane, sometimes fused to an aromatic ring.
- 1‑Phenyl‑2‑methylpiperidine.
- 1‑Phenyl‑3‑pyrrolidine‑2‑methylamine.
Heteroaromatic Amines
Compounds containing nitrogen within an aromatic heterocycle (pyridine, quinoline, isoquinoline) and additional aliphatic substituents.
- 3‑Phenyl‑2‑methyl‑pyridine.
- 2‑Methyl‑4‑phenyl‑pyrimidine (though pyrimidine has two nitrogens; thus this is an alternate isomer).
Aliphatic Amines
Linear or branched aliphatic chains terminating in a nitrogen atom, occasionally bearing an aromatic side chain.
- 1‑(Phenylmethyl)‑3‑methyl‑2‑aminopentane.
- 2‑(Phenyl)‑2‑methyl‑3‑aminopentane.
Synthesis
Multiple synthetic routes lead to C10H13N derivatives, each leveraging different functional group interconversions, catalytic processes, or biocatalytic transformations. The choice of route is typically guided by the desired substitution pattern, stereochemical requirements, and scale of production.
Aromatic Substitution and Cross‑Coupling
Direct C‑N bond formation can be achieved via Buchwald–Hartwig amination, where an aryl halide is coupled with an amine in the presence of a palladium catalyst and a suitable ligand. For instance, reacting 4‑bromobenzylamine with a secondary amine under these conditions yields a substituted aniline derivative with the required formula.
Reductive Amination
Reductive amination of aldehydes or ketones with ammonia or amine nucleophiles followed by reduction using NaBH4 or hydrogenation over a metal catalyst offers a versatile route. For example, condensation of benzaldehyde with a primary amine to form an imine, followed by catalytic hydrogenation, produces a benzylamine containing C10H13N.
Cyclization Reactions
Intramolecular cyclizations such as intramolecular Mannich reactions or reductive amination of cyclic ketones can generate nitrogen‑containing rings. An example is the cyclization of 3‑phenyl‑2‑methyl‑propionaldehyde with an amine to form a piperidine ring system.
Biocatalytic Routes
Enzymatic amination using transaminases can convert ketones to amines with high stereoselectivity. For C10H13N compounds containing chiral centers, biocatalysis provides a route to enantiomerically enriched products under mild conditions.
Physical and Chemical Properties
Although the general molecular formula is fixed, physical properties vary significantly across isomers due to differences in substitution patterns and ring systems. However, certain trends can be outlined.
- Melting points range from -40 °C for highly flexible aliphatic amines to over 150 °C for rigid aromatic amines.
- Boiling points typically lie between 130 °C and 220 °C, with higher values for compounds possessing extensive conjugation.
- Solubility in water is generally limited unless protonated; pKa values for these compounds are usually between 7 and 9, making them weakly basic.
- Density falls between 0.78 g·cm–3 and 0.95 g·cm–3, depending on the presence of bulky aromatic groups.
Spectroscopic Characterization
Characterization of C10H13N compounds relies on a combination of nuclear magnetic resonance (NMR), mass spectrometry (MS), infrared spectroscopy (IR), and ultraviolet-visible spectroscopy (UV‑Vis). Each technique provides complementary information about the electronic environment, mass, and functional groups present.
Proton NMR (¹H NMR)
Typical chemical shifts for aromatic protons appear between 7.0 and 8.5 ppm, while aliphatic protons resonate between 0.9 and 4.5 ppm. Nitrogen‑bearing methine or methylene groups often show multiplets due to coupling with neighboring protons. For example, a ¹H NMR spectrum of a 1‑phenyl‑2‑methylpiperidine displays a multiplet at ~1.2 ppm (three‑centered methyl group) and a broad singlet around 3.5 ppm (methylene adjacent to nitrogen).
Carbon NMR (¹³C NMR)
Carbonyl carbons (if present) resonate above 165 ppm. Aromatic carbons appear between 110 and 140 ppm, while aliphatic carbons fall below 80 ppm. DEPT experiments help distinguish CH, CH2, and CH3 groups.
Mass Spectrometry
Electron ionization (EI) spectra reveal a molecular ion at m/z 149. Loss of a methyl group (–15) or a hydrogen atom (–1) is common. High-resolution MS confirms the exact mass of 149.1023 Da for the [M]⁺ ion, consistent with C10H13N. Fragmentation patterns often show a base peak corresponding to the aromatic ring cation (C6H5⁺, m/z 77).
Infrared Spectroscopy
Key IR absorptions include: N–H stretching (3300–3500 cm–1 for primary amines, 3100–3300 cm–1 for secondary amines), aromatic C–H stretches (3050–3000 cm–1), aliphatic C–H stretches (2950–2850 cm–1), and C=C aromatic stretches (1600–1450 cm–1).
UV‑Visible Spectroscopy
Compounds containing extended conjugation display absorption bands in the 200–350 nm range. Aromatic amines typically exhibit a π–π* transition near 260 nm and a weaker n–π* transition near 320 nm.
Biological Activity and Pharmacology
Although C10H13N is a generic formula, many of its derivatives exhibit noteworthy biological activities. The presence of a nitrogen atom within a heterocyclic scaffold often confers affinity for neurotransmitter receptors or enzymes involved in metabolic pathways.
Central Nervous System (CNS) Activity
Several compounds, such as 4‑phenyl‑1‑piperidine derivatives, act as psychoactive agents, modulating dopaminergic or serotonergic pathways. Their structure–activity relationship (SAR) studies have demonstrated that the phenyl substituent enhances lipophilicity and brain penetration.
Antimicrobial Properties
Certain N‑alkylated anilines exhibit activity against Gram‑positive bacteria. The mechanism involves disruption of bacterial cell walls or inhibition of essential enzymes.
Enzyme Inhibitors
Some C10H13N compounds inhibit monoamine oxidase (MAO) by forming covalent adducts with the enzyme's active site. Structural analogues of 3‑phenyl‑1‑piperidinylamine have been evaluated for selective MAO‑B inhibition.
Other Pharmacological Activities
Examples include analgesic activity, antipsychotic potential, and anti‑inflammatory effects. These activities are often correlated with the compound’s ability to cross biological membranes and its metabolic stability.
Applications
Beyond pharmacology, C10H13N derivatives find use in various industrial and research contexts.
Pharmaceutical Intermediates
Compounds such as 1‑phenyl‑2‑methylpiperidine serve as key intermediates in the synthesis of β‑blockers, antihistamines, and antipsychotics. They are employed in the final stages of medicinal chemistry for the introduction of functional groups that enhance drug-like properties.
Materials Science
Amine‑containing monomers derived from C10H13N participate in the synthesis of cross‑linked polymers, adhesives, and surface‑active agents. Their nitrogen centers act as cross‑linking sites for epoxy resins and polyurethanes.
Agricultural Chemicals
Some derivatives are used as fungicides or insecticides. The amine group enhances binding to target proteins in pests, while the aromatic moiety improves lipophilicity for better bioavailability.
Research Reagents
Compounds with this formula are employed as ligands in coordination chemistry, as chromophores in photophysical studies, and as model systems for studying basicity and nucleophilicity.
Safety and Handling
While the general chemical nature is mild, individual isomers may exhibit hazardous properties.
- Flammability is moderate; many amines exhibit a flash point above 60 °C. Use of inert atmosphere or ventilation is recommended during synthesis.
- Corrosiveness is low to moderate; however, acid–base reactions with strong acids or bases can generate corrosive byproducts.
- Toxicity data indicate LC50 values for acute inhalation exposure ranging from 200 mg·m–3 to 500 mg·m–3, depending on the compound. Long‑term exposure studies have shown potential for liver and kidney effects.
- Precautions include use of gloves, goggles, and lab coats; working in a fume hood for volatile or flammable derivatives; and maintaining an inventory of first‑aid procedures for accidental ingestion or skin contact.
Key Isomer Examples
Below is a curated list of notable C10H13N compounds, their common names, and key properties. These examples illustrate the diversity achievable with this formula.
| Compound | SMILES | Formula | Molecular Weight | Melting Point (°C) | Boiling Point (°C) |
|---|---|---|---|---|---|
| 1‑Phenyl‑2‑methylpiperidine | CN1CCCCC1c1ccccc1C | C10H13N | 149.10 Da | 20–30 | 200 |
| 4‑Phenylmethyl‑2‑pyridine | CNc1ccccc1c1ccccc1 | C10H13N | 149.10 Da | −30 | 140 |
| 3‑Phenyl‑2‑methyl‑pyridine | CNc1ccc(C)cc1c1ccccc1 | C10H13N | 149.10 Da | −45 | 150 |
| 1‑(Phenylmethyl)‑3‑methyl‑2‑aminopentane | CNCCC(C)CPh | C10H13N | 149.10 Da | −20 | 120 |
| 2‑(Phenyl)‑2‑methyl‑3‑aminopentane | CNCC(C)CCPh | C10H13N | 149.10 Da | −30 | 130 |
Conclusion
Although the C10H13N formula is straightforward, the rich chemistry arising from its various substitution patterns, stereochemistry, and ring systems makes it a focal point of contemporary research. From scalable synthetic strategies and robust analytical protocols to diverse applications in medicine, materials, and agriculture, C10H13N derivatives occupy a vital position at the intersection of organic chemistry and applied sciences.
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