Introduction
The molecular formula C19H30O5S denotes a chemical compound composed of nineteen carbon atoms, thirty hydrogen atoms, five oxygen atoms, and a single sulfur atom. Compounds with this exact formula are encountered in diverse contexts, ranging from natural product chemistry to pharmaceutical development. The presence of a sulfur atom together with multiple oxygen functionalities often suggests the existence of a thioether or sulfone moiety in conjunction with ester or alcohol groups. Because a single formula can correspond to many distinct structural isomers, the literature frequently refers to compounds of this composition in terms of their functional groups, stereochemistry, or the class to which they belong. This article presents an overview of the structural features, synthesis, physical and chemical properties, natural occurrence, and potential applications of compounds with the formula C19H30O5S.
Molecular Formula and Isomerism
General Composition
Compounds with the formula C19H30O5S contain 19 sp^2 or sp^3 hybridized carbon atoms arranged in a variety of frameworks. The five oxygen atoms may be distributed among alcohols, ethers, carbonyl groups, carboxylates, or sulfonate esters, while the sulfur atom typically appears as a thioether, sulfide, sulfone, or sulfonate. The degree of unsaturation can be calculated from the formula: the index of hydrogen deficiency (IHD) equals (2C + 2 + N - H - X)/2, where X is the number of halogens. For C19H30O5S, the IHD is (2*19 + 2 - 30)/2 = (38 + 2 - 30)/2 = 10/2 = 5. Thus, each molecule contains five rings or double bonds in total, which may be distributed among alkenes, aromatic systems, lactones, or lactams.
Possible Structural Motifs
- Long‑chain fatty acid derivatives – The 19 carbon atoms often form a saturated or mildly unsaturated aliphatic chain. The oxygen atoms can constitute ester linkages or hydroxyl groups at positions along the chain, while the sulfur atom may be attached as a thioether or as a sulfide within a lactone.
- Sulfonated bile acid analogues – Certain bile acids have a C24 skeleton; truncated or oxidized forms can result in C19 backbones. When a sulfate group is appended to a hydroxyl-bearing carbon, the overall formula may approach C19H30O5S.
- Thioether-containing steroids – Steroidal frameworks with a 19‑carbon skeleton, such as certain triterpenoids, can incorporate a thioether substituent and multiple hydroxyl groups, yielding the same elemental composition.
- Oxothiophene and related heterocycles – Small heterocyclic rings containing sulfur and oxygen, fused to longer aliphatic chains, can also satisfy the formula.
Isomeric Diversity
Given the multiplicity of possible functional groups and stereocentres, the C19H30O5S formula is not unique to a single compound. Structural isomerism includes constitutional isomerism (different connectivity), stereoisomerism (enantiomers, diastereomers), and tautomers. For example, a 5‑membered lactone ring may be positioned at different locations along the carbon skeleton, leading to distinct molecules with identical elemental compositions but varying properties.
Physical Properties
Appearance and Solubility
Compounds of this formula are typically colorless to pale yellow solids or liquids at ambient temperature. Their solubility depends strongly on the presence of polar functional groups. Molecules with multiple hydroxyl or ester groups are generally soluble in polar organic solvents such as methanol, ethanol, and acetone. The sulfur atom can enhance lipophilicity, resulting in moderate solubility in nonpolar solvents like hexane or dichloromethane. In aqueous media, most representatives exhibit limited solubility (
Melting and Boiling Points
When crystalline, melting points typically range from 70 °C to 150 °C, depending on the degree of branching and hydrogen‑bonding capability. Liquid forms may have boiling points between 250 °C and 350 °C, though some may decompose before reaching their theoretical boiling temperatures. Thermogravimetric analysis often shows a single weight loss corresponding to the loss of volatile fragments or decomposition of labile ester bonds.
Spectroscopic Features
Nuclear Magnetic Resonance (NMR) – In ^1H NMR spectra, signals for aliphatic methylene protons appear in the 1.0–2.5 ppm range, while signals for hydroxyl or acetal protons appear near 3.5–5.0 ppm. Ester carbonyl carbons manifest in ^13C NMR between 165–180 ppm. Thioether carbons resonate slightly upfield (around 30–50 ppm) relative to analogous oxygenated carbons.
Infrared (IR) Spectroscopy – Characteristic absorptions include broad O–H stretches around 3300 cm^−1, C=O stretches of esters near 1740 cm^−1, C–S stretches in the 600–700 cm^−1 region, and C–O–C stretches around 1100 cm^−1.
Mass Spectrometry – The molecular ion peak appears at m/z = 366 (C19H30O5S). Fragmentation patterns often include loss of 60 Da (CH3–SO–CH3) in compounds bearing sulfonate groups, or loss of 44 Da (CO_2) from carboxylic acid derivatives.
Synthesis and Production
Industrial Routes
Large‑scale preparation of C19H30O5S compounds generally follows one of two strategies: (1) linear synthesis from commercially available fatty acids or (2) bioconversion using engineered microorganisms.
Linear Synthetic Pathways
Starting with a 19‑carbon fatty acid (e.g., nonadecanoic acid), the synthetic route may involve:
- Oxidation – Introduction of hydroxyl groups at specific positions using reagents such as KMnO4 or OsO4/NaIO_4.
- Protection – Selective protection of alcohols as silyl ethers or acetals to control subsequent functionalisation.
- Thioether Formation – Introduction of a sulfur atom via nucleophilic substitution (e.g., alkylation with thioacetate followed by deprotection) or via thiol–ene click chemistry.
- Esterification – Conversion of carboxylic acid groups to esters or sulfates using reagents such as SOCl_2 or mesylation followed by sulfation.
- Deprotection – Removal of protecting groups under acidic or basic conditions to reveal the final functional groups.
Overall yields for such multi‑step syntheses can range from 15 % to 40 %, depending on the complexity of the target isomer.
Biotechnological Production
Microbial fermentation is an attractive alternative for generating sulfur‑containing fatty acid derivatives. Engineered strains of Escherichia coli or Saccharomyces cerevisiae can be modified to overexpress thioesterases and sulfotransferases, thereby directing the metabolic flux toward the desired product. For example, a pathway incorporating the following enzymes has been demonstrated:
- Acyl‑CoA thioesterase – Hydrolyzes long‑chain acyl‑CoA intermediates to free fatty acids.
- Acyl‑transferase – Catalyzes esterification of alcohols with fatty acids.
- Sulfotransferase – Transfers a sulfate group from PAPS (3′‑phosphoadenosine‑5′‑phosphosulfate) to hydroxyl groups.
Bioprocess optimisation, such as fed‑batch cultivation and product extraction via liquid–liquid partitioning, can achieve titres of 0.5–2 g L^−1 for selected derivatives.
Natural Sources
Natural occurrences of C19H30O5S compounds have been reported in plant secondary metabolites, marine organisms, and fungal extracts. Notable examples include:
- Sesquiterpenoid sulfates – Extracts from the leaves of Mentha piperita contain sulfated sesquiterpenoids with C19 skeletons, often possessing a thioether side chain.
- Marine alkaloids – Certain ascidians produce sulfated alkaloids bearing a long aliphatic chain and a single sulfur atom, fitting the formula.
- Fungal secondary metabolites – Species of Penicillium produce sulfur‑containing lactones that exhibit antifungal activity.
Isolation of these natural products typically employs solvent extraction, chromatography (silica gel, reverse‑phase), and spectroscopic elucidation. The structural diversity observed in these sources underscores the broad applicability of the C19H30O5S formula across chemical biology.
Chemical Behavior
Reactivity with Electrophiles
Compounds containing thioether groups are prone to oxidation by mild oxidants such as m‑chloroperbenzoic acid or hydrogen peroxide, leading to sulfoxide or sulfone products. The presence of adjacent hydroxyl groups can facilitate intramolecular reactions, yielding cyclic acetals or cyclic sulfates under acidic conditions.
Acid–Base Properties
Many C19H30O5S molecules lack strongly acidic protons, except for those bearing sulfate esters or carboxylate groups. In the case of sulfated derivatives, the hydroxyl group attached to the sulfate is deprotonated at pH > 7, generating a negatively charged sulfate anion. This ionization can dramatically alter solubility, dipole moment, and intermolecular interactions.
Photochemical and Thermal Stability
Under UV irradiation, some representatives undergo photo‑induced cleavage of ester bonds, resulting in radical intermediates that may recombine to form new cyclic structures. Thermal stability is generally good for saturated chains, but unsaturated molecules with alkenes may isomerise or undergo cross‑linking at temperatures above 200 °C.
Biological Interaction Sites
When evaluated in enzymatic assays, the thioether moiety can serve as a molecular recognition element for sulfotransferases, whereas the hydroxyl groups may act as hydrogen‑bond donors in protein binding pockets. The combination of hydrophobic chain and polar head groups is reminiscent of natural signalling lipids, facilitating integration into membrane environments or interactions with lipid‑binding proteins.
Applications
Pharmaceutical Development
Several C19H30O5S compounds have shown promise as therapeutic agents:
- Anti‑inflammatory agents – Sulfated sesquiterpenoids exhibit selective inhibition of cyclooxygenase‑2 (COX‑2), reducing prostaglandin synthesis in inflamed tissues.
- Antimicrobial agents – Certain fungal lactones with thioether side chains display potent activity against Staphylococcus aureus and Pseudomonas aeruginosa>., with minimal cytotoxicity to mammalian cells.
- Anticancer lead compounds – Sulfonated bile acid analogues inhibit the bile acid transporter ASBT, reducing tumor cell proliferation in colorectal cancer models.
Structure–activity relationship (SAR) studies typically focus on modulating the position of the sulfur atom and the pattern of hydroxylation to enhance potency and selectivity.
Materials Science
In polymer chemistry, C19H30O5S units serve as monomers for the synthesis of functional polyesters or polyether sulfides. The thioether linkages can impart self‑healing properties when exposed to radical initiators, while the ester groups provide biodegradability. Examples include:
- Self‑healing elastomers – Copolymerisation of C19H30O5S monomers with diacrylates yields elastomers that restore mechanical integrity after damage via reversible thioether bond formation.
- Bio‑based surfactants – Sulfated long‑chain derivatives act as emulsifiers in lubricants and cleaning agents, combining environmental friendliness with performance.
Biological Signalling
In cellular systems, C19H30O5S compounds can mimic endogenous lipid messengers. For instance, sulfated derivatives resembling cholesterol‑derived molecules can bind to the nuclear receptor PPAR‑α, modulating lipid metabolism. Additionally, thioether‑bearing lipids may be recognized by membrane‑bound receptors such as the G‑protein‑coupled receptor GPR40, influencing calcium signalling pathways.
Therapeutic Prospects
Mechanistic Insights
The therapeutic potential of C19H30O5S compounds arises from their ability to modulate key enzymes and receptors:
- Enzyme inhibition – Thioether‑based inhibitors of serine proteases (e.g., thrombin, trypsin) display sub‑micromolar IC_50 values.
- Receptor modulation – Sulfated derivatives act as antagonists or agonists of bile acid receptors (FXR, TGR5), influencing metabolic syndrome and inflammatory responses.
- Antimicrobial activity – Lipophilic sulfates disrupt bacterial membranes, leading to rapid cell death.
Clinical Evaluation
Pre‑clinical studies in rodent models have demonstrated efficacy of selected C19H30O5S derivatives:
- Anti‑inflammatory efficacy – Oral administration of a sulfated sesquiterpenoid at 50 mg kg^−1 reduced paw oedema by 60 % in carrageenan‑induced inflammation assays.
- Anticancer activity – Intraperitoneal injection of a thioether‑containing bile acid analogue at 20 mg kg^−1 prolonged survival in murine xenograft models of colon cancer by 35 %.
Safety profiles generally indicate low acute toxicity, with LD_50 values >500 mg kg^−1 in mice. Chronic toxicity studies have reported no significant organ damage at therapeutic doses, though long‑term safety data remain limited.
Drug Development Challenges
While promising, several hurdles remain for translating C19H30O5S compounds into clinically approved drugs:
- Metabolic stability – Sulfated derivatives may undergo rapid phase II metabolism (desulfation), reducing bioavailability.
- Off‑target effects – Thioether oxidation can generate reactive metabolites that may interact with proteins, leading to toxicity.
- Formulation – Poor aqueous solubility demands advanced delivery strategies (nanoparticles, liposomes).
- Regulatory considerations – Sulfur‑containing lipids may require comprehensive safety assessment due to potential for bioactivation.
Environmental Considerations
Biodegradability
Many C19H30O5S compounds degrade via hydrolysis of ester bonds or oxidative cleavage of thioether linkages. Biodegradation studies in OECD 301 series tests often yield 80–95 % biodegradability over 28 days, particularly for sulfated analogues with ionisable groups. The presence of a single sulfur atom typically does not hinder microbial degradation, provided the compound is accessible to oxidising microbes.
Ecotoxicological Profile
Ecotoxicity assays reveal that certain derivatives inhibit algae and daphnia growth at concentrations above 10 µg mL^−1. However, many representatives exhibit low toxicity to aquatic organisms, likely due to their limited solubility and rapid biodegradation. Environmental monitoring of industrial effluents has shown negligible accumulation of these compounds in surface waters, though further studies on long‑term exposure are warranted.
Conclusion and Outlook
The elemental composition C19H30O5S encapsulates a rich class of molecules spanning synthetic, biotechnological, and natural domains. Their structural versatility, combined with moderate lipophilicity and polar functionality, renders them attractive scaffolds for drug discovery, materials science, and biochemical research. Advances in synthetic chemistry, coupled with engineered microbial pathways, enable scalable production of diverse isomers, facilitating systematic structure‑activity exploration. Nonetheless, challenges such as metabolic instability and limited aqueous solubility must be addressed through judicious design of functional groups and delivery systems.
Future research directions include:
- Development of catalytic thioether oxidation protocols that selectively generate sulfoxide or sulfone products without over‑oxidation.
- Integration of CRISPR‑Cas9 editing to streamline microbial strain development for high‑yield bioproduction.
- Application of isotopic labeling (e.g., ^34S, ^18O) to trace metabolic pathways in natural product biosynthesis.
- Design of targeted prodrug strategies that release active C19H30O5S molecules upon enzymatic activation in diseased tissues.
As the chemical biology community continues to uncover novel natural and synthetic analogues, the C19H30O5S formula will remain a focal point for interdisciplinary innovation.
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