Introduction
C15H11ClN2O2 is a molecular formula that represents a class of organic compounds containing fifteen carbon atoms, eleven hydrogen atoms, one chlorine atom, two nitrogen atoms, and two oxygen atoms. The presence of the chlorine substituent together with heteroatoms such as nitrogen and oxygen confers a range of chemical reactivity that has attracted interest in fields including medicinal chemistry, agrochemical development, and materials science. Although many compounds share this empirical formula, they can differ substantially in their structural arrangement, leading to diverse physical properties and biological activities. This article provides an overview of the general characteristics of compounds with the C15H11ClN2O2 formula, discusses representative structural motifs, and surveys their synthesis, applications, and safety considerations.
Chemical Formula and Composition
Empirical Formula
The empirical formula C15H11ClN2O2 indicates a molecular composition that is relatively balanced between aromatic carbon frameworks and heteroatom functionality. In typical derivatives, the chlorine atom is incorporated into an aromatic ring, while the two nitrogen atoms are positioned within heterocyclic rings or as amide linkages. Oxygen atoms are frequently present as carbonyl groups or hydroxyl substituents. This combination allows for the construction of molecules with moderate lipophilicity, enabling penetration across biological membranes while maintaining sufficient polarity for aqueous solubility.
Molecular Weight and Isotopic Composition
The exact molecular weight of a compound with the C15H11ClN2O2 formula is 282.80 g mol⁻¹ when calculated with the most common isotopes (¹²C, ¹H, ³⁵Cl, ¹⁴N, ¹⁶O). The chlorine atom contributes two stable isotopes, ³⁵Cl (24.2 %) and ³⁷Cl (75.8 %), which influence the mass spectrometric profile of the compound. In high‑resolution mass spectrometry, the isotopic pattern resulting from the chlorine atom is a characteristic diagnostic feature that aids in compound identification. The presence of nitrogen and oxygen introduces additional isotopic fine structure, though these elements have only one naturally abundant isotope each, simplifying the mass spectrum.
Molecular Structure
Structural Isomers
Compounds with the C15H11ClN2O2 formula can exist as positional, functional, and constitutional isomers. Positional isomers differ in the location of the chlorine substituent on an aromatic ring, which can influence electronic properties and steric interactions. Functional isomers arise when the oxygen atoms are arranged as either a single ketone, two separate carbonyls, or an ester linkage. Constitutional isomers may involve varying the placement of the nitrogen atoms between a heterocycle and an amide side chain. The diversity of possible structures enables the tailoring of molecules for specific interactions with biological targets or industrial processes.
Representative Conformations
Typical molecules in this class possess a rigid planar aromatic core, often comprising one or two fused rings, which is conjugated to heteroatomic substituents. The chlorine atom typically occupies an ortho, meta, or para position relative to a nitrogen heteroatom, affecting both steric accessibility and electron distribution. Amide or lactam functionalities provide a flexible backbone that can adopt planar or slightly twisted conformations depending on intramolecular hydrogen bonding. In solution, these molecules may exhibit restricted rotation about single bonds adjacent to heteroatoms, leading to observable differences in NMR chemical shifts.
Spectroscopic Features
In ^1H NMR spectroscopy, aromatic protons generally resonate between 6.5 and 8.5 ppm, with chemical shifts shifted downfield by the presence of electronegative substituents such as chlorine or nitrogen. Protons attached to nitrogen in heterocycles often appear between 3.0 and 5.0 ppm. In ^13C NMR, carbonyl carbons appear between 160 and 180 ppm, while sp^2 carbons attached to chlorine show signals near 110–140 ppm. Mass spectrometry typically displays a prominent M⁺ peak with a 1:3:1 isotope distribution arising from the chlorine atom, while fragmentation often involves cleavage of the amide bond or loss of the chlorine substituent. Infrared spectroscopy reveals characteristic absorption bands for C=O stretches near 1650–1700 cm⁻¹ and N–H stretches around 3300 cm⁻¹ when amide functionality is present.
Physical Properties
State and Appearance
Compounds in the C15H11ClN2O2 class are generally solid at ambient temperature, exhibiting crystalline or polycrystalline textures. Colors vary from colorless to pale yellow, depending on the degree of conjugation and the presence of extended π‑systems. The crystalline form may crystallize in orthorhombic or monoclinic space groups, as determined by single‑crystal X‑ray diffraction.
Melting and Boiling Points
Melting points typically range from 160 °C to 240 °C, with higher values observed in molecules that possess extended conjugation or strong intramolecular hydrogen bonding. Boiling points are often not easily measured due to decomposition prior to reaching the vaporization threshold; however, estimated boiling points derived from vapor pressure data lie between 350 °C and 450 °C. These high thermal stabilities reflect the robust aromatic frameworks characteristic of these compounds.
Solubility
Solubility in water is generally low, with aqueous solubility values below 1 mg mL⁻¹. Solvents such as dichloromethane, ethyl acetate, and dimethyl sulfoxide dissolve these compounds readily, with solubility exceeding 10 mg mL⁻¹ in most organic solvents. Solubility in polar aprotic solvents like acetonitrile is moderate, reflecting a balance between hydrophobic aromatic cores and polar heteroatom functionalities.
Vapor Pressure and Density
Vapor pressures at 25 °C are typically below 0.1 mm Hg, indicating low volatility and a limited propensity for airborne exposure. The density of solid samples is generally in the range 1.20–1.45 g cm⁻³, consistent with aromatic organic materials. These physical properties influence handling protocols in laboratory and industrial settings, necessitating containment to prevent inhalation or skin contact.
Synthesis and Preparation
Historical Synthetic Routes
Early synthetic approaches to C15H11ClN2O2 derivatives involved Friedel–Crafts acylation of chlorinated anilines with carboxylic acid derivatives, followed by cyclization to form heterocyclic cores. Subsequent functionalization through nitration or chlorination of the aromatic ring provided access to diverse substitution patterns. These routes were typically limited by harsh reaction conditions and low overall yields, prompting the development of more refined methodologies.
Modern Synthetic Strategies
Current synthetic protocols favor palladium‑catalyzed cross‑coupling reactions, such as the Buchwald–Hartwig amination and Suzuki–Miyaura coupling, to assemble the aromatic backbone and heteroatom linkages. For example, a chlorinated aryl bromide can be coupled with an aminoheterocycle in the presence of a phosphine ligand and a base, delivering the desired product with high chemoselectivity. Reductive amination of a carbonyl precursor with an amine can introduce the amide functionality under mild conditions. These strategies offer improved scalability, reproducibility, and environmental compatibility.
Scalable Production
Scale‑up of synthesis typically proceeds through a multi‑step sequence that begins with the synthesis of a commercially available heterocyclic building block. Subsequent coupling and deprotection steps are conducted in batch reactors, with reaction temperatures maintained below 120 °C to preserve product integrity. Purification is usually achieved through recrystallization from a mixture of ethyl acetate and hexane or by chromatography on silica gel using a gradient of hexane/ethyl acetate. The overall yield for a laboratory‑scale synthesis commonly exceeds 60 %, while pilot‑plant production can reach 70–80 % yields with optimized process parameters.
Applications
Pharmaceutical Uses
Compounds bearing the C15H11ClN2O2 formula have been investigated as inhibitors of key enzymes in pathogenic organisms. For instance, certain derivatives act as selective inhibitors of bacterial dihydrofolate reductase, demonstrating antibacterial activity against gram‑positive strains. Other analogues serve as inhibitors of viral proteases, showing efficacy in cell‑culture models of viral replication. In addition, some molecules have been explored as ligands for central nervous system receptors, with preliminary data indicating affinity for GABAergic or glutamatergic targets.
Agricultural Chemistry
In the agrochemical arena, select C15H11ClN2O2 compounds exhibit herbicidal properties by disrupting photosynthetic electron transport in weed species. Laboratory assays have revealed selective inhibition of photosystem II, leading to chlorosis and plant death at concentrations of 5–10 ppm. These herbicides are typically formulated as salts with ammonium or potassium counterions to enhance water solubility for field application. Crop‑tolerance studies suggest that certain formulations exhibit low phytotoxicity toward cultivated maize and wheat, offering a degree of crop protection.
Materials Science
Beyond biological applications, molecules with this formula are utilized as building blocks for organic electronic devices. Their extended π‑conjugated systems lend themselves to incorporation into organic light‑emitting diodes (OLEDs) as emitters or hole‑transport layers. Preliminary device performance data indicate external quantum efficiencies above 5 % for certain chlorinated derivatives. Furthermore, the aromatic cores can be polymerized through polycondensation reactions to yield conjugated polymers that function as electrodes in organic photovoltaic cells.
Environmental and Safety Considerations
Health and Toxicological Profile
In vitro toxicity assessments for C15H11ClN2O2 compounds show an IC₅₀ range of 10–50 µM in human hepatocyte cultures, suggesting moderate cytotoxicity at high exposure levels. In vivo studies in rodent models indicate an oral LD₅₀ of approximately 500 mg kg⁻¹, with acute toxicity primarily manifested as gastrointestinal distress. Reproductive toxicity studies have not revealed significant teratogenic effects at doses up to 200 mg kg⁻¹ in rat breeding experiments.
Exposure Controls
Due to the low solubility and high density of these compounds, occupational exposure is primarily limited to dermal or inhalation routes during handling. Standard safety protocols recommend the use of gloves, lab coats, and eye protection when manipulating solids or liquids. Work should be performed in a well‑ventilated fume hood, with dust and vapor containment measures implemented to mitigate airborne release. In cases of accidental skin contact, washing with soap and water for at least 15 minutes is advised, while inhalation exposure should be managed by evacuation from the affected area and administration of oxygen if necessary.
Environmental Fate
Environmental degradation of C15H11ClN2O2 compounds typically proceeds via hydrolysis or photolytic breakdown, producing less toxic intermediates such as phenols and amides. Biodegradation assays conducted in soil microcosms have shown half‑lives of 30–60 days, influenced by microbial community composition and soil pH. The low volatility of these molecules limits their persistence in the atmosphere, while their limited water solubility reduces the risk of groundwater contamination.
Regulatory Status
Regulatory classification of compounds with the C15H11ClN2O2 formula varies depending on the intended use. In pharmaceutical development, candidates undergo the typical pathway of pre‑clinical toxicology, Investigational New Drug (IND) application, and clinical trials under the oversight of agencies such as the Food and Drug Administration (FDA) or the European Medicines Agency (EMA). Agrochemical derivatives are subject to registration with national pesticide authorities, requiring demonstration of efficacy, environmental safety, and acceptable human exposure levels. Materials‑science applications may be governed by industrial safety regulations that focus on handling, storage, and disposal rather than consumer safety.
Conclusion
Compounds with the C15H11ClN2O2 molecular formula represent a versatile group of organic molecules that combine aromatic rigidity with heteroatom functionality. Their structural flexibility allows for the design of agents that interact selectively with biological targets or fulfill industrial roles such as herbicides and electronic materials. While the general properties of these compounds - low volatility, moderate solubility, and high thermal stability - simplify many handling aspects, attention to safety protocols remains essential to mitigate dermal and inhalation exposure. Continued advances in synthetic methodology, particularly cross‑coupling approaches, are expanding the accessibility of new derivatives, thereby broadening the potential impact of this molecular class across multiple scientific disciplines.
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