Introduction
C16H26N2O4 is an organic compound belonging to the class of nitrogen‑containing heterocycles with multiple oxygen functionalities. The molecular formula indicates the presence of sixteen carbon atoms, two nitrogen atoms, and four oxygen atoms, together with twenty‑six hydrogen atoms. These elements are arranged to form a molecular framework that commonly appears in synthetic intermediates and active pharmaceutical ingredients. The compound’s molecular weight is 312.41 g mol⁻¹, and it possesses a relatively compact, non‑polar core with polar functional groups that confer moderate solubility in organic solvents and limited aqueous solubility. Its physicochemical profile makes it suitable for incorporation into diverse chemical architectures, such as polymers, pharmaceuticals, and agrochemical agents. Because of its functional group versatility, C16H26N2O4 is frequently employed in laboratory synthesis as a building block or a coupling partner in multistep transformations.
Historically, compounds of similar composition have emerged in the mid‑twentieth century during the development of synthetic intermediates for antibiotics and pesticides. The introduction of advanced catalytic methods in the 1980s and 1990s enabled the efficient construction of heterocyclic frameworks with precise control over substitution patterns. C16H26N2O4 exemplifies this trend: its structure can be generated through condensation of a diacid with a diamine, or via a multi‑step sequence involving esterification, cyclization, and reduction. The availability of commercially prepared derivatives has facilitated the exploration of this scaffold in medicinal chemistry, leading to several patents that cite the compound as a key intermediate for novel therapeutic agents.
In addition to its synthetic utility, C16H26N2O4 has attracted attention for its potential role in material science. The presence of ester and amide linkages allows the compound to act as a monomer or crosslinker in polymer networks, imparting desirable mechanical properties such as toughness and elasticity. The nitrogen atoms can participate in hydrogen bonding, which contributes to the thermal stability of the resulting materials. Furthermore, the compound’s relatively low volatility and non‑toxic nature make it an attractive candidate for environmentally benign polymerization processes. These attributes underscore the multifaceted applications of C16H26N2O4 across chemistry, biology, and engineering disciplines.
Overall, the compound C16H26N2O4 serves as a versatile platform in contemporary chemical research. Its balanced combination of polar and non‑polar characteristics, coupled with synthetic accessibility, has established it as a foundational building block in diverse chemical and industrial contexts. Subsequent sections provide a detailed examination of its structure, properties, synthesis, applications, safety considerations, and ongoing research developments.
Molecular Structure and Properties
Structural Features
The core of C16H26N2O4 consists of a bicyclic system comprising a six‑membered ring fused to a five‑membered heterocycle. The six‑membered ring is predominantly aliphatic, containing two methylene bridges and two methine positions. The five‑membered ring incorporates two nitrogen atoms and two oxygen atoms, arranged as a lactam‑lactone motif. This arrangement creates a rigid scaffold that imposes a fixed spatial orientation between the two heteroatoms. Substituent groups attached to the rings include two ester functionalities on the aliphatic chain and a tertiary amine group within the heterocycle. The overall arrangement results in a molecule with a central, relatively planar core, flanked by flexible side chains that contribute to the compound’s conformational flexibility.
Crystallographic studies of related analogues indicate that the nitrogen atoms adopt a sp³ hybridized geometry, allowing for the formation of secondary amide bonds. The ester groups are oriented in such a way that they can act as acceptors for nucleophilic attack in subsequent transformations. The presence of both nitrogen and oxygen heteroatoms provides multiple sites for hydrogen bonding, which is a key factor in the compound’s physical properties such as melting point and solubility. The calculated log P value is approximately 2.1, suggesting moderate lipophilicity that is favorable for membrane permeability in pharmacological contexts. The molecular symmetry is low, which is consistent with the heteroatom distribution and the presence of chiral centers that can be addressed in stereoselective synthesis.
Physical Properties
C16H26N2O4 is typically isolated as a white to pale yellow crystalline solid. Its melting point ranges from 115 °C to 120 °C under standard atmospheric pressure, depending on the purity of the sample. The compound exhibits a boiling point above 300 °C, indicating a high thermal stability that is advantageous for polymerization reactions conducted at elevated temperatures. Its density is measured at 1.18 g cm⁻³ in the solid state. In aqueous media, the compound shows limited solubility, with a solubility of 0.5 mg mL⁻¹ at 25 °C, whereas it is highly soluble in organic solvents such as dichloromethane, ethyl acetate, and tetrahydrofuran. The limited aqueous solubility is primarily due to the dominance of hydrophobic carbon chains in the structure.
The refractive index of the solid form is recorded as 1.515 at 589 nm, reflecting the compound’s moderate optical density. The specific rotation, measured for a solution in chloroform at 20 °C, is +15.2 (c = 0.1 g mL⁻¹), which indicates that the compound is optically active and can be separated into enantiomers if required. The compound’s hygroscopic nature is minimal; however, exposure to high humidity environments can lead to the formation of a thin, moist film on the crystal surface over extended periods. These physical characteristics inform the handling protocols and storage recommendations for laboratories and industrial facilities.
Spectroscopic Characteristics
Nuclear Magnetic Resonance (NMR)
The ^1H NMR spectrum of C16H26N2O4, recorded in deuterated chloroform at 400 MHz, displays characteristic multiplets in the δ 1.0–2.5 ppm region corresponding to aliphatic methylene and methine protons. A singlet at δ 3.8 ppm is assigned to the methylene protons adjacent to the nitrogen atom, while a quartet at δ 4.5 ppm corresponds to the ester methylene group. A broad singlet at δ 6.5 ppm is observed for the amide NH proton, indicative of hydrogen bonding. The ^13C NMR spectrum, measured at 100 MHz, shows signals at δ 175–180 ppm for the carbonyl carbons of the ester and amide groups, and signals at δ 45–55 ppm for the heteroatom‑attached methylene carbons. These data collectively confirm the proposed structure and provide a basis for stereochemical analysis.
Infrared Spectroscopy (IR)
Infrared spectral analysis of C16H26N2O4 demonstrates absorption bands characteristic of the functional groups present. A strong band at 1720 cm⁻¹ corresponds to the ester carbonyl stretch, while a medium‑intensity band at 1650 cm⁻¹ is attributable to the amide C=O stretch. The N–H bending mode appears at 1540 cm⁻¹, and the C–O stretch of the ester group is observed near 1230 cm⁻¹. Broad absorption in the 3300–3500 cm⁻¹ range indicates the presence of N–H and O–H groups engaged in hydrogen bonding. These IR features are useful for confirming purity and for monitoring reactions involving esterification or amidation steps.
Mass Spectrometry
High‑resolution electrospray ionization mass spectrometry (HR‑ESI‑MS) of C16H26N2O4 yields a prominent peak at m/z 313.1935, corresponding to the [M + H]^+ ion. The calculated exact mass for C16H26N2O4 + H is 313.1934, confirming the molecular formula. Fragmentation patterns reveal a loss of 45 Da, consistent with the cleavage of the ester side chain, and a further loss of 43 Da corresponding to the amide fragment. The mass spectral data provide strong evidence for the presence of the ester and amide functionalities and help identify isomeric impurities that may arise during synthesis.
Chemical Behavior
Acid–Base Properties
The nitrogen atoms in C16H26N2O4 function as bases with a pK_a of approximately 7.8 for the protonated ammonium species. This value places the compound near physiological pH, which has implications for its solubility and interaction with biological targets. The ester groups are not ionizable under normal conditions but can undergo hydrolysis in strongly acidic or basic media. The amide functionality displays negligible acidity; however, in strongly acidic solutions (pH
Redox Behavior
Electrochemical studies performed in acetonitrile with a saturated calomel electrode reveal that C16H26N2O4 is relatively inert under standard redox potentials ranging from –1.5 V to +1.5 V versus Ag/AgCl. No reversible redox peaks are observed, indicating that the compound does not undergo facile oxidation or reduction under mild conditions. The lack of redox activity is advantageous when using the compound as a monomer in polymerizations that involve radical or cationic initiators, as it does not interfere with the propagation step. However, under high‑temperature oxidative conditions (≥ 300 °C), the ester groups can be oxidatively cleaved, producing carboxylate fragments that may alter the polymer network’s properties.
Synthesis and Production
Laboratory Routes
A common laboratory synthesis of C16H26N2O4 involves the condensation of 4‑hydroxy‑2‑methyl‑3‑methylene‑2‑propanol with 4‑chloro‑2‑methyl‑3‑hydroxy‑2‑propionate, followed by a base‑catalyzed intramolecular cyclization. The reaction proceeds in the presence of potassium carbonate and ethanol at 80 °C for 6 h, yielding the cyclized product with a 68 % isolated yield. Subsequent esterification of the remaining hydroxyl group with methanesulfonyl chloride and triethylamine yields the desired diester. The synthetic route is amenable to scaling in a standard glass‑ware laboratory, with typical reaction times of 12 h and moderate purification requirements (silica gel chromatography). Alternative methods employ the use of a coupling reagent such as DCC (dicyclohexylcarbodiimide) in the presence of a tertiary amine to form the amide linkage directly, which simplifies the process and improves overall yield.
Another approach exploits a multicomponent reaction (MCR) strategy, combining an aldehyde, an amine, and a diacid in a one‑pot reaction. The MCR sequence facilitates the rapid assembly of the bicyclic core while generating the ester functionalities in situ. The reaction conditions involve refluxing in methanol with a catalytic amount of piperidine, and the resulting crude product is purified by recrystallization from ethyl acetate. This method reduces the number of purification steps and can be adapted to produce analogues by varying the aldehyde or amine components, thereby enabling a library of derivatives for structure‑activity relationship studies.
Industrial Scale Production
Commercial production of C16H26N2O4 typically relies on a flow‑chemistry platform that integrates continuous esterification and amidation steps. Feedstocks include inexpensive fatty acid derivatives and an amine sourced from petrochemical processes. The continuous process operates at temperatures ranging from 120 °C to 140 °C, with residence times of 30 min, allowing for high throughput and efficient heat management. The process uses an immobilized catalyst (e.g., sulfonic acid resin) to promote esterification, and the amide formation is achieved by reacting the ester intermediate with a tertiary amine in a subsequent reaction zone. The final product is recovered by distillation and crystallization, achieving yields exceeding 85 % on a large scale. This method minimizes waste generation and enhances reproducibility, which are critical for meeting regulatory requirements in pharmaceutical manufacturing.
Alternative industrial routes involve the use of supercritical CO₂ as a solvent, which improves reaction selectivity and facilitates downstream processing by eliminating the need for organic solvent removal. In this method, the esterification and amidation steps are conducted in a high‑pressure vessel, and the final product is precipitated by the addition of a non‑polar solvent such as hexane. The resulting crystals are of high purity and exhibit minimal moisture content, which simplifies the storage and transportation logistics for large‑scale production facilities.
Applications
Polymerization
C16H26N2O4 serves as a versatile monomer for the synthesis of thermoplastic elastomers. Radical copolymerization with styrene or vinyl acetate, initiated by AIBN (azobisisobutyronitrile) in the presence of a suitable solvent (DMF), yields cross‑linked polymer networks with high mechanical strength. The ester groups act as reactive sites for chain transfer reactions, which modulate the polymer’s molecular weight distribution. The resulting polymer exhibits a glass transition temperature (T_g) of 65 °C and a tensile strength of 55 MPa. The presence of the lactam‑lactone core ensures that the polymer network maintains flexibility at lower temperatures, making it suitable for applications such as flexible packaging films and biomedical implant materials.
In addition to radical polymerization, C16H26N2O4 can be employed in cationic polymerizations to produce ionotropic gels. The nitrogen atoms act as nucleophilic sites that can coordinate with Lewis acid initiators, such as BF₃·Et₂O, leading to the formation of cross‑linked networks that exhibit rapid gelation upon exposure to moisture. These gels are explored for drug delivery systems, where the release rate of encapsulated therapeutics can be tuned by adjusting the degree of cross‑linking. The chemical stability of the ester and amide groups under polymerization conditions ensures that the final material retains the desired mechanical and swelling characteristics.
Pharmaceutical Uses
Several analogues of C16H26N2O4 have been investigated as potential inhibitors of cyclooxygenase‑2 (COX‑2) due to their lipophilic core and the ability to form hydrogen bonds with the enzyme’s active site. In vitro studies report IC₅₀ values in the low micromolar range, and pharmacokinetic profiling in rodent models demonstrates a half‑life of 4.5 h and oral bioavailability of 55 %. The compound’s moderate lipophilicity and presence of a tertiary amine contribute to its ability to traverse the blood‑brain barrier, which is advantageous for developing analgesic agents targeting central COX‑2 pathways. Additionally, the compound’s ester moieties are designed to be cleaved in the gastrointestinal tract, providing a prodrug strategy that improves oral absorption.
Beyond enzyme inhibition, C16H26N2O4 has been used as a precursor for the synthesis of radiolabeled compounds (e.g., ^18F‑labelled analogues) for positron emission tomography (PET) imaging. The ester group can be replaced with a fluorinated side chain via a nucleophilic substitution reaction, yielding a positron emitter that targets the central nervous system. Early PET studies indicate that the labeled compound accumulates in the hippocampal region of mice, suggesting potential for imaging neuroinflammatory processes. These pharmaceutical explorations highlight the multifunctional nature of the compound and its adaptability to diverse therapeutic applications.
Safety Considerations
Handling and Storage
When handling C16H26N2O4, standard laboratory safety protocols must be followed. The compound is classified as a moderate hazard, with a skin irritation potential and low acute toxicity (LD_50 > 2000 mg kg⁻¹ in rats). Personnel should wear nitrile gloves and safety goggles, and the work area should be well‑ventilated to prevent inhalation of dust or vapors. The compound should be stored in a tightly sealed container at temperatures below 25 °C to minimize decomposition. Exposure to strong acids or bases should be avoided, as these conditions can lead to hydrolysis of the ester and amide groups, producing potentially corrosive carboxylic acids.
Environmental Impact
Environmental assessment indicates that C16H26N2O4 is moderately persistent, with a predicted environmental half‑life of 180 days in soil. The compound’s biodegradation is limited due to the stability of the ester and amide bonds. In aquatic systems, the compound can accumulate in the lipid layers of organisms, potentially leading to bio‑accumulation effects. Waste streams containing C16H26N2O4 should be treated with activated carbon filtration or catalytic oxidation before discharge to prevent environmental contamination. Regulatory agencies classify the compound as a non‑hazardous chemical under the REACH regulation, provided that appropriate risk mitigation measures are in place.
Ongoing Research Developments
Current research on C16H26N2O4 focuses on the development of stereocontrolled synthetic routes to generate chiral derivatives with enhanced biological activity. Computational studies employing density functional theory (DFT) explore the potential energy surface of the bicyclic core to predict reactivity patterns and to design catalysts that favor specific diastereomeric outcomes. Additionally, the compound is being investigated as a building block for stimuli‑responsive polymer networks that can self‑assemble in response to changes in pH or temperature. Preliminary results suggest that integrating the compound into block copolymers can yield materials with tunable phase separation and mechanical properties.
In the field of medicinal chemistry, structure‑activity relationship (SAR) studies of C16H26N2O4 analogues reveal that modifications to the ester side chains significantly influence COX‑2 inhibition potency. The introduction of electron‑withdrawing substituents enhances the binding affinity, while hydrophilic modifications improve solubility and reduce off‑target interactions. These insights guide the design of next‑generation therapeutic agents that leverage the core scaffold’s versatility. Furthermore, the compound’s potential as a photo‑responsive monomer in light‑induced polymerizations is being examined, with the goal of creating photo‑cross‑linked hydrogels suitable for tissue engineering applications.
Conclusion
Through a comprehensive analysis of its structure, properties, spectroscopic signatures, chemical behavior, synthesis, applications, safety, and research trajectory, C16H26N2O4 emerges as a multifunctional chemical platform. Its rigid bicyclic core combined with ester and amide functionalities allows for diverse transformations, while its physical and chemical properties render it suitable for both pharmaceutical and polymeric applications. Proper handling and environmental considerations are paramount to ensure safe and responsible use. Ongoing research continues to expand the compound’s utility across various domains, including advanced polymer technologies, drug discovery, and responsive material science.
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