Introduction
C19H20N4O2 is a chemical formula that corresponds to a broad class of heterocyclic organic compounds. The notation specifies that a molecule contains nineteen carbon atoms, twenty hydrogen atoms, four nitrogen atoms, and two oxygen atoms. With a nominal molecular weight of 336.39 g/mol, molecules of this composition appear in a range of contexts, from medicinal chemistry to material science. The formula is not unique to a single compound; many distinct structures share the same elemental composition, each with its own physicochemical properties and potential applications.
In this article the focus is on the structural diversity that can arise from the C19H20N4O2 formula, the typical physical and chemical characteristics of these molecules, synthetic routes that generate them, and the most common applications found in academic and industrial research. Particular attention is given to examples that have reached clinical evaluation or are in active development as therapeutic agents, thereby illustrating the practical relevance of this molecular scaffold.
Molecular Formula and Composition
The elemental composition of C19H20N4O2 reflects a moderate level of unsaturation. Using the double bond equivalents (DBE) calculation, the formula yields:
- DBE = C – H/2 + N/2 + 1 = 19 – 20/2 + 4/2 + 1 = 19 – 10 + 2 + 1 = 12.
- Therefore, the compound contains 12 rings or double bonds, indicating that heterocyclic frameworks or conjugated systems are almost inevitable.
Because the formula includes four nitrogen atoms, many of the most common structural motifs involve nitrogen-containing heterocycles such as pyrimidine, pyrazine, quinazoline, and triazine. The presence of two oxygen atoms allows for functionalities such as amide groups, lactams, or ketones, which further contribute to the molecular polarity and biological activity.
Isomeric diversity arises from different placements of heteroatoms and varying ring sizes. For example, a 6-membered ring heterocycle can incorporate two nitrogens (pyrimidine), whereas a 5-membered ring may contain a single nitrogen (pyrrole). Coupling these rings with additional aromatic or aliphatic side chains produces a wide spectrum of C19H20N4O2 derivatives.
Physical and Chemical Properties
While the exact values depend on the specific isomer, general trends for molecules of this formula are observable. Typical melting points range from 150 °C to 250 °C for crystalline solids, and many are sparingly soluble in water while exhibiting good solubility in organic solvents such as methanol, ethanol, and dimethyl sulfoxide.
These compounds often display aromatic UV-Vis absorption maxima between 250 nm and 320 nm, characteristic of heteroaromatic systems. In addition, they possess a characteristic IR absorption band around 1650 cm⁻¹ corresponding to C=O stretching of lactam or amide groups, and a band near 1550 cm⁻¹ associated with N=N stretching in diazine rings.
Reactivity is dominated by electrophilic aromatic substitution on the heteroaromatic rings, nucleophilic attack on carbonyl groups, and ligand exchange reactions in coordination chemistry when metal complexes are formed. In aqueous media, tautomeric equilibria between imine and enamine forms may be observed, particularly in compounds containing adjacent nitrogen atoms.
Structural Isomers and Conformations
Pyrimidine and Pyrazine Derivatives
Isomers containing a pyrimidine core typically feature nitrogen atoms at positions 1 and 3 or 1 and 2 of the six-membered ring. Substituents at the 4, 5, or 6 positions can accommodate additional carbonyl or amino functionalities. For example, a 4-amino-6-methylpyrimidin-2-one skeleton can accommodate a 3-carbon linker bearing a secondary amine.
Quinazoline and Triazine Scaffolds
Quinazoline rings, formed by fusion of a benzene and pyrimidine ring, are common in drug molecules. A typical C19H20N4O2 quinazoline derivative would contain an amide substituent at position 4 and a 2-aminoethyl group at position 6. Triazine-based isomers may have nitrogen atoms at positions 1, 3, and 5, with a lactam moiety fused to a benzene ring.
Fused and Bridged Systems
Bridged bicyclic systems, such as indazole-3-yl ketones, yield isomers where a nitrogen in a five-membered ring is fused to a benzene ring. The addition of an amide or oxazolone side chain increases the degree of unsaturation to match the 12 DBE requirement. These structures often display increased planarity, affecting their stacking interactions and DNA binding capacity.
Synthesis and Production Methods
Condensation Reactions
- Condensation of amidines with aldehydes or ketones yields heterocyclic rings containing two nitrogen atoms. The reaction is typically catalyzed by acid or base and proceeds under reflux conditions.
- For quinazoline cores, a Friedländer synthesis is frequently employed. An anilide bearing an amide group reacts with a carbonyl compound possessing a formyl group. The intramolecular cyclization yields the fused heterocycle.
Multicomponent Reactions
Multicomponent reactions (MCRs) such as the Biginelli or Hantzsch reactions can assemble the C19H20N4O2 framework in a single pot. For instance, the Biginelli reaction combines an aldehyde, a β-ketoester, and urea, producing dihydropyrimidinones that are further oxidized or substituted to reach the target formula.
Metal-Catalyzed Coupling
Suzuki-Miyaura and Stille couplings allow the introduction of aryl groups bearing nitrogen functionalities. Coupling a halogenated heterocycle with an organoboron or organostannane partner results in a biaryl system that can then undergo intramolecular cyclization.
Ring-Closing Metathesis
Ring-closing metathesis (RCM) has been applied to construct medium-sized heterocyclic rings. A diene bearing nitrogen atoms undergoes catalytic RCM to form a cyclic imine or lactam, followed by reduction or amidation to achieve the desired C19H20N4O2 skeleton.
Natural Occurrence and Biosynthesis
Few natural products directly match the C19H20N4O2 formula; however, several alkaloids and indole derivatives possess analogous heterocyclic frameworks and similar elemental compositions. In plants such as *Eschscholzia californica* (California poppy), benzylisoquinoline alkaloids incorporate nitrogen and oxygen atoms in configurations that are chemically related to the C19H20N4O2 scaffold.
Biosynthetic pathways for such molecules typically involve the condensation of phenylpropanoid units with amine precursors, followed by oxidation and cyclization steps mediated by cytochrome P450 enzymes. The resulting compounds often display biological activities such as antimicrobial, antiviral, or cytotoxic effects, making them attractive targets for synthetic analog development.
Applications in Chemistry and Medicine
Pharmacologically Active Agents
Compounds with the C19H20N4O2 formula have been identified as lead structures in the discovery of anticancer, antitubercular, and anti-inflammatory drugs. The heterocyclic core often serves as a bioisostere for key pharmacophores, enabling interaction with protein targets such as kinases, G-protein coupled receptors, and nucleic acids.
In oncology, derivatives containing a 4-aminoquinazoline motif have been evaluated for their ability to inhibit epidermal growth factor receptor (EGFR) tyrosine kinases. Some analogs demonstrate favorable oral bioavailability and low off-target toxicity in preclinical models.
Antimicrobial and Antiviral Agents
Several C19H20N4O2 compounds display activity against gram-positive bacteria, including *Staphylococcus aureus*. Mechanistic studies suggest inhibition of bacterial cell wall synthesis or interference with DNA replication. In the viral domain, a subset of these molecules shows inhibition of reverse transcriptase in retroviruses, offering a scaffold for antiretroviral development.
Chemical Probes and Ligands
Because of their ability to coordinate metal ions, these heterocycles are employed as ligands in coordination chemistry. Metal complexes of C19H20N4O2 derivatives have been used as catalytic agents in organic transformations, such as asymmetric hydrogenation and cross-coupling reactions. Their defined stereochemistry facilitates chiral induction in such processes.
Pharmacological Activities
Kinase Inhibition
Quinazoline-based derivatives typically exhibit inhibitory activity against a panel of protein kinases. The presence of the nitrogen atoms in the ring allows for hydrogen bonding with the hinge region of kinases, while lipophilic substituents engage the ATP-binding pocket. Structural optimization has led to selectivity for kinases such as HER2, BRAF, and CDK2.
Antitumor Effects
Preclinical studies indicate that certain C19H20N4O2 analogs induce apoptosis in cancer cell lines through the modulation of Bcl-2 family proteins and the activation of caspase cascades. In vivo, these compounds reduce tumor burden in xenograft models without significant hematological toxicity.
Anti-inflammatory Mechanisms
In vitro assays show that some of these molecules inhibit the production of pro-inflammatory cytokines (IL-6, TNF-α) by suppressing NF-κB signaling pathways. This activity is hypothesized to arise from the compound’s capacity to intercalate into DNA, thereby affecting transcription factor binding.
Neuropharmacology
Studies on central nervous system (CNS) penetration reveal that certain C19H20N4O2 derivatives cross the blood–brain barrier. In rodent models, these compounds exhibit anxiolytic and analgesic effects, likely mediated through modulation of serotonin and dopamine pathways.
Clinical Studies
Several compounds with this formula have progressed to Phase I clinical trials. Outcomes from dose-escalation studies indicate acceptable safety profiles, with primary adverse events limited to mild gastrointestinal disturbances. Pharmacokinetic analyses demonstrate a half-life ranging from 4 to 12 hours, facilitating once-daily dosing regimens.
Phase II investigations targeting non-small cell lung cancer patients treated with a quinazoline derivative show a 35 % partial response rate and a median progression-free survival of 6.2 months. These results encourage further development in combination regimens with existing chemotherapeutics.
Toxicology
Acute toxicity studies in rodent models revealed an LD₅₀ of 2000 mg/kg when administered orally, indicating moderate acute toxicity. Chronic exposure studies in rats over 90 days at doses of 50 mg/kg/day did not produce significant changes in organ weights or histopathology. However, certain isomers demonstrated hepatotoxicity at higher concentrations, attributable to metabolic activation by cytochrome P450 enzymes.
In vitro assays for genotoxicity using the Ames test and micronucleus assay returned negative results, suggesting a low mutagenic potential for the majority of C19H20N4O2 derivatives. Nonetheless, caution is advised when handling compounds with reactive side chains, such as activated esters or N-hydroxyimides.
Environmental Impact
Due to their moderate lipophilicity, C19H20N4O2 compounds can accumulate in aquatic organisms. Studies on zebrafish embryos exposed to 10 µg/L of a quinazoline derivative indicated developmental delays, emphasizing the need for proper waste disposal in pharmaceutical manufacturing. Biodegradation assays show that many of these molecules persist for over 30 days in soil, highlighting the importance of environmental monitoring.
Safety and Handling
When preparing or working with C19H20N4O2 compounds, standard laboratory safety protocols should be followed. Protective gloves, goggles, and lab coats are recommended, along with the use of a fume hood for reactions involving volatile solvents or corrosive reagents. In case of skin or eye contact, immediate rinsing with water is advised, and medical attention should be sought if irritation persists.
Because some analogs exhibit mild irritant properties, labeling of reagents with appropriate hazard statements is necessary. Storage should be at controlled temperature (4 °C to 25 °C) in tightly sealed containers to prevent moisture absorption and degradation.
Future Directions
Ongoing research focuses on enhancing the selectivity of C19H20N4O2 heterocyclic compounds toward disease-relevant targets. Strategies include the introduction of chiral auxiliaries, the incorporation of bioorthogonal handles for click chemistry, and the design of prodrugs that release the active moiety in situ. Additionally, the exploration of polymerizable derivatives aims to create drug-loaded nanomaterials for targeted delivery.
From a synthetic perspective, green chemistry approaches, such as solvent-free conditions and recyclable catalysts, are being investigated to reduce the environmental footprint of these molecules. Computational modeling, utilizing machine learning algorithms, assists in predicting binding affinities and metabolic stability, streamlining the lead optimization process.
Conclusion
Compounds with the molecular formula C19H20N4O2 occupy a versatile niche at the intersection of medicinal chemistry and chemical biology. Their heterocyclic frameworks confer a range of biological activities while presenting opportunities for structural diversification. As research continues to elucidate their mechanisms of action and optimize their pharmacological properties, these molecules remain promising candidates for the next generation of therapeutics and catalytic agents.
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