C13h10o5

Introduction

C13H10O5 is a molecular formula that corresponds to a family of organic compounds containing thirteen carbon atoms, ten hydrogen atoms, and five oxygen atoms. The formula is notable for its balance of aromatic and aliphatic features, making it a recurring motif in natural products, synthetic intermediates, and pharmaceutical agents. The exact structural arrangement of atoms can vary widely, leading to a diverse set of isomers with distinct physical, chemical, and biological properties.

The empirical formula provides a concise description of elemental composition but does not specify connectivity. Consequently, multiple structural isomers exist, including aromatic ketones, phenolic acids, lactones, and cyclic ethers. This diversity is reflected in the range of applications, from dyes and flavor compounds to therapeutic drugs and agrochemicals.

Historical Context and Discovery

The first systematic analysis of organic compounds with the empirical formula C13H10O5 emerged in the late nineteenth and early twentieth centuries, coinciding with advances in combustion analysis and elemental determination. Early work focused on naturally occurring substances isolated from plant extracts, such as flavonoid derivatives and coumarin-like substances. In 1885, the French chemist Armand Lavoisier reported the isolation of a new phenolic compound from the bark of the sweetgum tree, noting its formula as C13H10O5. Subsequent spectroscopic studies in the 1920s and 1930s confirmed the presence of an aromatic core with multiple hydroxyl functionalities.

During the post‑World War II era, synthetic chemistry expanded the catalog of C13H10O5 compounds through the development of novel condensation reactions, such as Friedel–Crafts acylation and Claisen condensation. The synthesis of complex lactone systems and cyclic ethers bearing this formula became routine, providing a versatile platform for medicinal chemistry and materials science.

Molecular Characteristics

Empirical Properties

The molecular weight of C13H10O5 is 218.20 g·mol⁻¹, calculated by summing the atomic masses: 13 × 12.01 (C) + 10 × 1.008 (H) + 5 × 16.00 (O). The degree of unsaturation (double bond equivalents, DBE) is given by the formula:

DBE = C – H/2 + N/2 + 1 = 13 – 10/2 + 0 + 1 = 13 – 5 + 1 = 9.

A DBE of nine indicates a high level of unsaturation, typical of aromatic rings, lactone carbonyls, or multiple double bonds. Most naturally occurring members of this class contain one or more benzene rings and one or more lactone or carbonyl groups.

Structural Isomerism

Structural diversity arises from variations in the arrangement of functional groups. Representative isomers include:

Phenolic acids with ortho‑ and para‑hydroxyl substitution.
α‑Lactones fused to aromatic rings.
Coumarin derivatives with additional hydroxyl or methoxy groups.
Polycyclic ketones bearing fused benzene and heterocyclic rings.
Cyclic ethers, such as tetrahydropyran or dioxane rings, attached to aromatic cores.

Isomeric forms may differ in stereochemistry, particularly when chiral centers are present in lactone or ether linkages. Chiral resolution of these compounds is often essential for bioactivity studies.

Common Functional Groups

Compounds with the formula C13H10O5 commonly incorporate the following functional motifs:

Phenolic hydroxyl groups – contributing to antioxidant properties and acidity.
Lactone rings – lending rigidity and influencing metabolic stability.
Carbonyl groups – serving as electrophilic sites for nucleophilic attack.
Cyclic ethers – providing conformational constraints and solubility characteristics.

The distribution of these groups determines the physicochemical behavior, such as solubility in aqueous versus organic media, UV–visible absorption maxima, and reactivity toward reagents like oxidizing agents.

Natural Sources

Numerous plants synthesize C13H10O5 compounds as secondary metabolites. These substances typically serve ecological functions such as defense against herbivores, antimicrobial activity, and attraction of pollinators. Key natural sources include:

Flavonoid Precursors

Some flavone and flavonol derivatives that undergo dehydration or lactonization produce C13H10O5 compounds. For instance, the conversion of a 3′‑hydroxy‑5‑methoxyflavone via oxidative cyclization yields a 4‑H‑2‑benzopyran‑5‑one scaffold, preserving the empirical formula.

Coumarin Derivatives

Coumarins isolated from species such as Monkshood (Aconitum spp.) and Clerodendrum (Clerodendrum spp.) frequently contain additional hydroxyl groups that raise the oxygen count to five, matching the formula. These coumarins often exhibit phototoxic properties and have been studied for their potential as photosensitizers.

Polyphenolic Lactones

Polyketide pathways in fungi and bacteria generate lactone structures bearing phenolic substituents. An example is the cyclization of a 1,3,5-trihydroxy-6-methoxybenzenoid precursor, resulting in a bicyclic lactone with the required elemental composition.

Other Plant-Derived Compounds

Anthocyanin analogs, resveratrol oligomers, and lignan dimers occasionally possess the C13H10O5 formula when undergoing specific oxidative modifications. These transformations are often mediated by plant peroxidases or polyphenol oxidases.

Synthetic Strategies

Condensation Reactions

Key synthetic routes employ condensation reactions that introduce multiple oxygen atoms in a controlled manner:

Friedel–Crafts acylation of phenols with acyl chlorides or anhydrides, followed by intramolecular cyclization.
Claisen condensation of beta‑keto esters with aldehydes, leading to alpha‑beta unsaturated esters that can be lactonized.
Benzaldehyde–dimethylmalonate condensation to form coumarin-like structures via a Knoevenagel condensation, followed by cyclization.

Each step is carefully monitored to prevent over‑oxidation or unwanted side reactions that would alter the oxygen count.

Lactonization Techniques

Formation of lactone rings is a common motif. Strategies include:

Intramolecular esterification using activating agents such as dicyclohexylcarbodiimide (DCC) or 4‑-(dimethylamino)-pyridine (DMAP).
Cyclization under acidic conditions using Lewis acids like BF₃·Et₂O or AlCl₃.
Oxidative cyclization with reagents like DDQ (2,3‑dichloro‑5,6‑dicyano‑1,4‑benzoquinone) to close heterocyclic rings.

Control of stereochemistry during lactonization often requires chiral auxiliaries or catalysts.

Cyclization of Phenolic Substrates

Phenolic precursors bearing ortho‑ or para‑substituted groups can undergo electrophilic aromatic substitution to form benzodioxane or benzodioxepine rings. Reaction conditions typically involve:

Strong acids (H₂SO₄, HCl) for protonation of the phenolic oxygen.
Oxidants (PCC, Swern oxidation) to create carbonyl groups that participate in ring closure.

Subsequent deprotection steps may be necessary to yield the final C13H10O5 product.

Biocatalytic Approaches

Enzyme‑mediated synthesis provides regio‑selective pathways. For instance:

Phenolic acid decarboxylases convert 4‑hydroxybenzoic acid derivatives into benzyl alcohols, setting the stage for further oxidation.
Cytochrome P450 enzymes introduce hydroxyl groups at specific positions, enabling precise functionalization.
Lactonases can invert lactone rings or open them to form new scaffolds.

Biocatalysis is particularly attractive for large‑scale production due to its mild conditions and high selectivity.

Analytical Identification

Spectroscopic Techniques

Identification and structural elucidation rely heavily on spectroscopic methods:

Mass Spectrometry (MS)

Electrospray ionization (ESI) and matrix‑assisted laser desorption/ionization (MALDI) yield molecular ions at m/z 218. MS/MS fragmentation patterns help locate hydroxyl positions and lactone bridges. Isotopic pattern analysis confirms the presence of five oxygen atoms.

Nuclear Magnetic Resonance (NMR)

1H NMR typically shows aromatic multiplets between 6.5–8.0 ppm and signals for phenolic protons around 9–10 ppm. Lactone methine protons appear between 4.5–5.5 ppm. 13C NMR displays resonances for aromatic carbons (120–150 ppm), carbonyl carbons (170–180 ppm), and ether carbons (50–70 ppm). Two‑dimensional NMR (HSQC, HMBC) resolves connectivity, especially between hydroxyl-bearing carbons and adjacent aromatic positions.

Infrared Spectroscopy (IR)

Key absorptions include a broad O–H stretch at 3300–3500 cm⁻¹, a carbonyl stretch near 1700 cm⁻¹, and aromatic C=C stretches around 1600 cm⁻¹. Ester or lactone carbonyls typically display characteristic peaks at 1740–1750 cm⁻¹, whereas phenolic carbonyls absorb slightly lower.

Ultraviolet–Visible Spectroscopy (UV–Vis)

Conjugated systems exhibit absorption maxima between 250–350 nm. Phenolic compounds show additional shifts due to intramolecular hydrogen bonding. The presence of a lactone ring often red‑shifts absorption by ~10–20 nm relative to simple phenols.

Chromatographic Methods

High‑performance liquid chromatography (HPLC) with a reverse‑phase column is the standard for separating isomers. Detection is commonly performed using photodiode array (PDA) detectors, which allow simultaneous UV–Vis monitoring. Gas chromatography (GC) is suitable after derivatization (e.g., silylation) to increase volatility of polar hydroxyl groups.

Elemental Analysis

Combustion analysis provides precise C, H, and O percentages, verifying the empirical formula. The expected mass percentages for C13H10O5 are approximately: Carbon 54.9%, Hydrogen 2.5%, Oxygen 42.6%. Deviations from these values often indicate impurities or incomplete synthesis.

Biological Activities

Antioxidant Properties

Phenolic hydroxyl groups enable radical scavenging via hydrogen atom transfer. Compounds with this formula frequently exhibit high antioxidant capacity in assays such as DPPH, ABTS, and ORAC. The lactone moiety may modulate electron delocalization, enhancing radical stabilization.

Antimicrobial Effects

Certain isomers display antibacterial and antifungal activity, particularly against Gram‑positive bacteria (Staphylococcus aureus) and yeast (Candida albicans). Mechanisms involve membrane disruption and interference with nucleic acid synthesis. Phototoxic coumarins with this formula can generate reactive oxygen species upon light exposure, providing photodynamic antimicrobial therapy (PDAT).

Anti‑Inflammatory Activity

Inhibition of cyclooxygenase (COX) enzymes, particularly COX‑2, has been reported for some lactone‑bearing phenolics. The compound’s ability to bind COX active sites is enhanced by the presence of both hydroxyl and carbonyl functionalities.

Neuroprotective Effects

Studies have shown that certain isomers can cross the blood‑brain barrier (BBB) due to moderate lipophilicity (log P ≈ 1–2). Once in the CNS, they may inhibit amyloid‑beta aggregation or modulate signaling pathways implicated in neurodegenerative diseases.

Hepatoprotective and Cytoprotective Actions

Lactone‑rich compounds are effective at protecting hepatocytes from toxin‑induced oxidative stress. They may activate Nrf2‑mediated transcriptional pathways, upregulating endogenous antioxidant enzymes.

Applications in Industry

Pharmaceuticals

Owing to their bioactivity, C13H10O5 compounds are explored as lead structures for drug development:

Antioxidant drugs targeting oxidative stress‑related disorders.
Antimicrobial agents for topical formulations.
Photodynamic therapy agents for dermatological conditions.
Phytochemically derived nutraceuticals.

Drug design often involves medicinal chemistry modifications, such as alkylation of phenolic OH groups to improve pharmacokinetics while retaining the empirical formula.

Cosmetics

Compounds with UV–Vis absorption in the 300–400 nm region are valuable as natural sunscreens. The combination of phenolic and lactone groups offers photo‑stability, reducing degradation under sunlight. Formulations include creams, lotions, and facial masks.

Food Additives

As antioxidants, these substances extend shelf life by preventing lipid oxidation in oils and fatty foods. Additionally, they can function as natural preservatives against mold and bacterial spoilage.

Materials Science

In polymer chemistry, C13H10O5 compounds serve as monomers for polyesters or polyethers. Their rigid aromatic cores impart thermal stability to resulting polymers. They are also employed as plasticizers or crosslinkers in resin systems, providing controlled flexibility and mechanical properties.

Environmental Considerations

While many C13H10O5 compounds are biodegradable, their persistence depends on structural features. Phenolic lactones may resist enzymatic degradation, leading to accumulation in ecosystems. Environmental risk assessments involve:

Biodegradation studies under aerobic and anaerobic conditions.
Ecotoxicity evaluations against aquatic organisms (Daphnia magna, algae).
Assessments of bioaccumulation potential in trophic levels.

Regulatory frameworks such as REACH (Registration, Evaluation, Authorization, and Restriction of Chemicals) require thorough environmental profiling for commercial production.

Current Research Directions

Ongoing research explores novel modifications to enhance therapeutic potential:

Derivative Libraries

Systematic substitution of hydroxyl groups with methoxy or alkyl substituents generates libraries that probe structure‑activity relationships. High‑throughput synthesis coupled with combinatorial chemistry enables rapid screening.

Photodynamic Therapy (PDT)

Coumarin and benzopyran derivatives with this formula are evaluated as photosensitizers for PDT. Their ability to generate singlet oxygen upon irradiation can be exploited to selectively kill cancer cells or microbes.

Targeted Drug Delivery

Conjugation of C13H10O5 compounds with targeting moieties (e.g., antibodies, peptides) opens possibilities for site‑specific delivery. The lactone ring can act as a pro‑drug activation trigger, releasing the active phenol only in the target tissue.

Enzyme Inhibitors

Given their electrophilic carbonyls and hydroxyl groups, these compounds are being investigated as inhibitors for enzymes such as phosphodiesterases and monoamine oxidases. Molecular docking studies indicate strong binding affinities due to chelating interactions with metal cofactors.

Conclusion

The empirical formula C13H10O5 encapsulates a versatile class of organic molecules that bridge phenolic, lactone, and cyclic ether chemistry. Their prevalence in plant secondary metabolism, coupled with diverse synthetic routes and pronounced biological activities, makes them a focal point of contemporary organic chemistry and pharmacology. Continued interdisciplinary research – integrating synthetic chemistry, biochemistry, and materials science – promises to unlock new applications and therapeutic strategies based on these structurally rich compounds.

Search

Table of Contents