Introduction
C13H11NO3 denotes a molecular formula that represents a class of organic compounds containing thirteen carbon atoms, eleven hydrogen atoms, one nitrogen atom, and three oxygen atoms. This empirical composition is shared by multiple structurally distinct molecules, including aromatic amides, heterocyclic derivatives, and phenolic compounds. The formula does not uniquely identify a single substance; rather, it serves as a descriptor that can be used to classify a range of substances with similar stoichiometric ratios. The compounds that fall under this formula are of interest in medicinal chemistry, materials science, and organic synthesis due to their diverse physicochemical properties and biological activities.
Molecular Formula Overview
Stoichiometric Significance
The ratio C13:H11:N1:O3 can be interpreted as the simplest whole-number representation of the elemental composition of a molecule. From this ratio, one can infer that the molecule likely contains an aromatic system or a conjugated framework, as the high carbon count relative to hydrogen suggests multiple unsaturations. The presence of a single nitrogen atom often indicates an amide, imide, or heterocyclic nitrogen. Three oxygen atoms could be distributed as carbonyl groups, hydroxyl groups, or ether linkages.
Common Structural Motifs
- Aromatic amide: a benzamide core substituted with additional phenyl or heteroaromatic rings.
- Imide: a bicyclic structure containing two carbonyl groups adjacent to a nitrogen.
- Phenoxy ketone: a phenolic ring connected to a ketone group through an ether linkage.
- Heteroaromatic nitrogen-containing rings: such as pyridine or quinoline fused with carbonyl functionalities.
Structural Isomerism
Constitutional Isomers
Isomers sharing the same formula but differing in connectivity arise from the various ways the atoms can be arranged. For C13H11NO3, typical constitutional isomers include:
- p-Acetamidophenyl phenyl ketone
- 2-Phenyl-1,3-benzodioxin-4-one
- 3-(3-Methylphenyl)quinazolin-4-one
Each isomer exhibits distinct functional groups that influence reactivity, solubility, and biological interactions.
Geometric Isomers
In molecules containing double bonds adjacent to sp2-hybridized carbons, cis-trans isomerism can occur. For example, a styryl derivative with an amide group may adopt E or Z configurations across the C=C bond. Such isomerism can markedly affect melting points and binding affinities in biological systems.
Representative Compounds
Acetylated Benzophenone Derivatives
A common family within this formula class is the acetylated benzophenone derivatives. One well-known member is 4-(4'-Acetylphenyl)phenyl ketone, which has applications as a precursor to chromophores and dyes. The molecule displays a central ketone linked to two phenyl rings, one of which bears an acetyl group. This arrangement offers a balance between lipophilicity and polar functional groups, influencing its optical properties.
Heterocyclic Nitrogen Compounds
Compounds such as 4-quinazolinone analogues also fit the C13H11NO3 formula. These heteroaromatic frameworks incorporate a nitrogen atom within a fused benzene-pyrimidine system and a lactam functionality. The nitrogen atom can engage in hydrogen bonding, enhancing aqueous solubility, while the lactam carbonyl provides sites for nucleophilic attack during synthesis.
Phenoxy Ketone Structures
Phenoxy ketones featuring a phenoxy group attached to a carbonyl are another subset. An example is 2-phenyl-4-phenoxybutan-2-one, where a tertiary ketone is flanked by two aromatic rings via an ether linkage. Such molecules are useful in the design of fluorescent probes due to intramolecular charge transfer characteristics.
Physical and Chemical Properties
Melting and Boiling Points
Compounds with the C13H11NO3 formula generally exhibit melting points ranging from 150°C to 240°C, reflecting their aromatic content and hydrogen-bonding capacity. Boiling points are typically above 350°C under atmospheric pressure, necessitating high-temperature distillation or recrystallization techniques for purification.
Solubility Profile
Solubility is influenced by the balance between hydrophobic aromatic rings and polar functional groups. Many of these molecules show moderate solubility in polar organic solvents such as ethanol, acetone, and dimethyl sulfoxide. In contrast, water solubility is usually limited unless the compound contains ionizable groups or additional hydroxyl functionalities.
Spectroscopic Features
In the infrared region, characteristic absorptions include carbonyl stretches around 1700–1720 cm⁻¹ for amide or ketone groups, and aromatic C–H stretches near 3000–3100 cm⁻¹. UV–vis spectra often display strong absorption bands in the 280–350 nm range due to π–π* transitions, with possible bathochromic shifts when conjugation extends through heteroatoms.
Synthesis Methods
Condensation Reactions
A common synthetic route involves the condensation of an aryl amine with a diketone under acidic or basic conditions, forming an amide linkage. For example, the reaction of aniline with benzophenone under reflux in acetic acid yields a 4-phenylbenzamide derivative, which can subsequently undergo acetylation to reach the target formula.
Cross-Coupling Strategies
Transition-metal-catalyzed cross-coupling reactions, such as Suzuki-Miyaura or Buchwald-Hartwig amination, allow the assembly of complex aryl-nitrogen frameworks. Starting from a boronic acid and an aryl halide, a palladium catalyst can introduce the nitrogen functionality while preserving the oxygen-containing groups.
Oxidative Cyclization
Oxidative cyclization of ortho-phenolic amides using hypervalent iodine reagents provides access to quinazolinone structures. The iodine(III) oxidant mediates C–C bond formation between the amide nitrogen and the adjacent aromatic ring, closing the heterocyclic system.
Applications
Medicinal Chemistry
Several C13H11NO3 derivatives have been investigated as pharmacophores for anticancer, antiviral, and anti-inflammatory activity. The lactam or ketone moieties act as hydrogen-bond acceptors, facilitating interaction with enzyme active sites or receptor binding pockets. For instance, a 4-quinazolinone analog has shown activity against epidermal growth factor receptor (EGFR) kinases.
Photophysical Materials
Compounds possessing extended conjugation and electron-donating groups are employed as chromophores in organic light-emitting diodes (OLEDs) and fluorescence sensors. Their emission spectra can be tuned by modifying substituents on the aromatic rings, allowing for customizable color outputs.
Agricultural Agents
Some molecules with this formula serve as intermediates in the synthesis of herbicides or pesticides. The presence of both amide and phenoxy groups can contribute to moderate lipophilicity, aiding in plant uptake and bioavailability.
Biological Activity
Enzyme Inhibition
Amide and ketone functionalities are common motifs in enzyme inhibitors. The carbonyl group can coordinate with metal ions in metalloprotein active sites, while the nitrogen atom provides a potential hydrogen-bond donor or acceptor. Studies have demonstrated inhibition of acetylcholinesterase and carbonic anhydrase by structurally related compounds.
Receptor Binding
Heterocyclic nitrogen-containing compounds often target G-protein-coupled receptors (GPCRs) or nuclear receptors. The planar structure facilitates π–π stacking with aromatic amino acid residues, enhancing binding affinity. Modulating the electronic properties of the nitrogen atom can alter receptor selectivity.
Antioxidant Properties
Phenolic derivatives within this formula class can scavenge free radicals by donating hydrogen atoms from hydroxyl groups. The presence of electron-withdrawing carbonyls stabilizes the resulting phenoxy radicals, contributing to antioxidant efficacy in cellular assays.
Safety and Toxicology
Acute Toxicity
Many of the described compounds exhibit low acute toxicity when administered orally at moderate doses. However, higher concentrations can lead to central nervous system depression or hepatotoxicity, depending on the substitution pattern.
Chronic Exposure
Long-term exposure studies suggest potential endocrine-disrupting effects for certain phenoxy ketone derivatives. Bioaccumulation in fatty tissues has been observed in animal models, necessitating careful assessment of dose-response relationships.
Handling Precautions
Laboratory handling of C13H11NO3 compounds requires standard protective equipment: gloves, goggles, and lab coat. Many of these molecules are flammable in solvent form and should be stored in cool, well-ventilated areas away from oxidizing agents.
Environmental Impact
Biodegradability
Structural features such as amide bonds can be susceptible to hydrolytic degradation, but the aromatic core often confers resistance to microbial metabolism. Consequently, persistence in aquatic environments can be moderate to high, depending on the specific substituents.
Ecotoxicity
Studies on aquatic organisms reveal varying degrees of toxicity. Compounds with phenoxy groups have shown acute toxicity to fish and invertebrates at concentrations above 0.1 mg/L. Chronic exposure can impair reproduction and growth.
Regulatory Status
Certain C13H11NO3 derivatives are classified under hazardous substance regulations due to their potential for environmental persistence and toxicity. Management of waste streams containing these compounds is governed by local chemical safety guidelines.
Analytical Techniques
Chromatographic Separation
- Thin-layer chromatography (TLC) using silica gel plates with a hexane/ethyl acetate solvent system effectively separates isomeric derivatives.
- High-performance liquid chromatography (HPLC) with a reverse-phase C18 column and a gradient of acetonitrile/water (with 0.1% formic acid) allows for precise quantification of mixture components.
Mass Spectrometry
Electrospray ionization (ESI) in positive mode typically yields [M+H]+ peaks at m/z 227.1 for the parent ion, with fragmentation patterns revealing loss of CO, NH3, or phenyl groups. Matrix-assisted laser desorption/ionization (MALDI) can be employed for larger conjugated analogs.
Spectroscopic Characterization
Proton nuclear magnetic resonance (¹H NMR) spectra display aromatic multiplets between 7.0 and 8.5 ppm, carbonyl signals in the 10–12 ppm range, and aliphatic protons near 2.5–4.0 ppm. Carbon-13 NMR confirms the presence of carbonyl carbons around 190–200 ppm. Infrared spectroscopy provides complementary data on functional group vibrations.
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