Imidic Acid Research Articles

A Spectroscopic and In Silico Description of the Non-Covalent Interactions of Phthalic Acid Imide Derivatives with Deoxyribonucleic Acid-Insights into Their Binding Characteristics and Potential Applications.

The treatment of cancer represents one of the most significant challenges currently facing modern medicine. The search for new drugs that are effective in the treatment of patients is an ongoing endeavor. It is frequently the case that the molecular target of anticancer drugs is a DNA molecule. The therapeutic effect of a drug is achieved by influencing the structure of a macromolecule or by inhibiting its function. Among the synthetic substances with potential anticancer effects, particular attention should be paid to phthalic acid imide derivatives. Three phthalimide derivatives are employed in the treatment of multiple myeloma: thalidomide, pomalidomide, and lenalidomide. Nevertheless, the search for new derivatives with a diverse range of biological activities is ongoing. In light of the above, the subject of our investigation is four non-toxic phthalic acid imide derivatives. The objective was to analyze the interaction of these compounds with DNA. The use of spectroscopic and in silico methods has enabled us to demonstrate that all of the tested analogs can act as ligands for deoxyribonucleic acid, forming non-covalent bonds with it. All four compounds tested interact with the ctDNA molecule, binding in its minor groove. The most stable complex is formed here between deoxyribonucleic acid and the C derivative, in which the -CF3 group is attached to the benzene ring. What is interesting and important, the described mechanism of action is analogous to that observed between ctDNA and thalidomide, pomalidomide, and lenalidomide.

Diels–Alder Adducts of <i>N</i>-Substituted 2-Pyridones with Maleinimides. Synthesis and Antiviral Activity

Adducts of N-substituted 2-pyridones [pyridine-2(1H)-ones] and N-substituted maleic acid imides were synthesized under thermal conditions of the Diels–Alder reaction with yields from 68 to 97%. Cytotoxicity and antiviral activity of the obtained compounds were studied using a model of adenovirus infection [human adenovirus type 5 (AdV5)] in MA-104 cell culture. It was shown that the synthesized adducts have low toxicity and medium antiviral activity. Only 9-hexyl-2-phenyl-3a,4,7,7a-tetrahydro-1H-4,7-(epiminomethano)isoindole-1,3,8-trione has the most pronounced viral inhibitory properties with a selectivity index of 7.

Tetraaza macrocyclic complexes of Cu(II), Co(III) and Ni(II) derived from template condensation of 2,6-pyridinedicarbohydrazide and 2,6-diacetylpyridine: Stability investigation and coloring properties on plastics

Completely conjugated 14-membered ring hexaaza ligand complexes of Cu(II), Co(III) and Ni(II) were synthesized by the template cyclo-condensation reaction of 2,6-diacetylpyridine and 2,6-pyridinedicarbohydrazide: [Cu(HL)Cl]·1.35H2O (1), [Cu(HL)Br]·CH3OH (2), [Cu(L)(H2O)]·4H2O (3), [Co(HL)Cl2]·CH3OH (4), (H3O)[Co(H2L)Cl2][Co(HL)Cl2]Cl2·H2O (5), [Co(HL)(SCN)2]·CH3OH (6), [Ni(L)]·3H2O (7) and (H3O)[Ni(L)]Cl·H2O (8). The structure of all complexes derived from this novel diprotic macrocyclic ligand H2L (5,7-dimethyl-3,4,8,9-tetraaza-1,6(2,6)-dipyridinacyclodecaphane-4,7-diene-2,10-dione) were determined by single crystal X-ray diffraction method. The tetraaza 14-membered conjugated macrocycle is N4-tetracoordinated to metal, adopts an essentially planar configuration and forms four fused metallocycles rings, two five-membered and two six-membered chelates. The structures of the studied complexes reveal three isomers out of three possible: with a 5-6-5-6 order of alternation of metallocycles for 1–6, the 5-5-6-6 isomer in 8 and the coexistence of two different isomers with 5-5-6-6 and 6-6-5-5 alternation of metallocycles in 7. Based on the protonation state of the macrocyclic ligand, four forms of the ligand have been registered: bis-deprotonated L2− (compounds 3, 7 and 8), monodeprotonated HL− (1, 2 and 4), neutral H2L (5) and for compound 6 tautomeric (amide → imidic acid) HL− form. The organisation of crystal structures 1–8 depends on the nature of the metal and the composition of the solvents and outer-sphere ions, but shows clear common features for the same type of metal. The hydrolytic study demonstrated a high stability of the Co(III) and Ni(II) complexes in acidic solutions and the most thermally stable are the complexes 3 and 7 with the limit of 350 °C for Ni(II) complex. Testing of the coloring properties of the [Ni(L)] (8) complex on plastics indicates a high coloring efficiency, especially for polyamide polymers.

Synthesis, experimental and computational studies of new (trifluorosilyl)propyl derivatives of cyclic imides of dicarboxylic acids

New (trifluorosilyl)propyl derivatives of cyclic dicarboxylic acid imides 1-[3-(trifluorosilyl)propyl]pyrrolidine-2,5‑dione, 1-[3-(trifluorosilyl)propyl]piperidine-2,6‑dione and 2-[3-(trifluorosilyl)propyl]-1H-isoindole-1,3(2H)‑dione were synthesized and structurally characterized by FTIR, NMR spectroscopy, mass spectrometry and elemental analysis. Intramolecular coordination interaction O→Si and the influence of the hydrocarbon chain length on the strength of the coordination interaction in Si-fluoroethyl and Si-fluoropropyl derivatives of cyclic imides of dicarboxylic acids were characterized by DFT calculations. The geometric, energetic and electronic characteristics of the investigated molecules were also determined. The intramolecular O→Si coordination bond, closing the six-membered chelate cycle SiCCN(C=O), is observed in the (trifluorosilyl)ethyl derivative phthalimide in the gas, and in the (trifluorosilyl)ethyl derivative succinimide the O→Si coordination bond is observed both in the gas phase and in DMSO solution. The coordination bond O→Si, closing the seven-membered chelate cycle SiCCCN(C=O), is found in the (trifluorosilyl)propyl derivative succinimide in the gas phase. Quantum chemical calculations were carried out at the M06/6–311G** and MP2/6–311++G**//M06/6–311G** levels with the 6–311G** basis set.

Photoredox Catalytic Access to N,O-Acetals from Enamides by Means of Electron-Poor Perylene Bisimides.

N,O-acetals are found as structural motifs in natural products and are important synthetic precursors for N-acylimines as building blocks in organic synthesis for C-C-bond formation and amines. For the synthesis of N,O-acetals, an acid-, base- and metal-free catalytic method is reported applying N,N-di-(2,6-diisopropyl)-1,7-dicyano-perylen-3,4,9,10-tetracarboxylic acid imide and N,N-di-(2,6-diisopropyl)-1,6,7,12-tetrabromo-2,5,8,11-tetracyano-perylen-3,4,9,10-tetracarboxylic acid imide as extremely electron-deficient photocatalysts. The first perylene bisimide highly selectively photocatalyzes the formation of the N,O-acetals as products in high yields, and the second and more electron-deficient perylene bisimide allows these reactions without thiophenol as an H-atom transfer reagent. Calculated electron density maps support this. The reaction scope comprises different substituents at the nitrogen of the enamides and different alcohols as starting material. Dehydroalanines are converted to non-natural amino acids which shows the usefulness of this method for organic and medicinal chemistry.

Kinetics of direct and water‐mediated tautomerization reactions of five‐membered cyclic amides or lactams

AbstractAs part of a series of studies of hydrogen‐atom transfer or tautomerization reactions of imidic acid–amide species, , we report the rate constants for a set of 24 five‐membered cyclic compounds at low, 50–300 K, and high, 500–1500 K, temperatures. These rate constants are for both the high temperature direct reaction and for that mediated by an additional water molecule which facilitates the hydrogen transfer reaction at low temperatures. In the latter case we show that the rate of reaction from a pre‐reaction complex can be rapid at temperatures down to 50 K on a 1 ms timescale and is dominated by quantum mechanical effects as evaluated by small‐curvature and quantised‐reaction‐states tunnelling. In addition, we present thermochemical data such as enthalpies of formation, entropies, isobaric heat capacities and enthalpy functions for these largely unknown species which span a range of compounds from pyrolidinone to oxo‐tetrazoles.

Tartaric acid new derivatives as prospective and safe alternative to antimicrobials for food products packing

Introduction: Multi-drug resistance of pathogens and food spoilage bacteria is one of the most prevalent problems in contemporary science because the microbial adaptation potential is permanently being stimulated by the excessive antibiotic usage by mankind. In this research, seven new derivatives of tartaric acid (TA) were studied. Their high activity against the multi-drug resistant bacteria and the biodegradation potential by soil microflora was demonstrated.Objective: Based on multiple literature data about aldaric acids antimicrobial properties, for combating pan-drug and especially multi-drug resistant pathogenic microbes, natural L-tartaric acid was target-derivatized by cyclohexyl-, phenyl-, benzyl- and ethanolamine- functional groups into complex amino salts and cyclic imides, which have demonstrated the significant bactericidal and bacteriostatic activity against the spoilage agent bacteria, as well as phytopathogenic and human opportunistic pathogens.Results: In vitro analyses of TA ethanolamine- benzyl-, cyclohexyl- and phenyl- imides and complex amino salts have shown that the mentioned substances are highly active agents for combating multi-drug resistant Gram-positive and Gram-negative pathogens and food spoilage microbes, such as: Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Klebsiella pneumonia, Salmonella enteritidis, Staphylococcus aureus, etc. These compounds are biodegradable by P. chlororaphis group non-pathogenic bacteria and their resistance is ensured by genes of nucleoid as well as are not transmitted by plasmids. In silico analyses have demonstrated their alternative mechanism of action. Conclusions: The results suggest that TA new derivatives can be potentially recommended as safe alternative antimicrobials for food packaging.Keywords: tartaric acid imides, tartaric acid complex aminosalts, spoilage microorganisms, antimicrobial activity, multi-drug resistance.

АЦИЛИРОВАНИЕ N-ФОСФОРИЛИРОВАННЫХ ЦИАНОАЦЕТИМИДАТОВ

A method has been developed for the preparation of organophosphorus derivatives of imidic acids, based on the acylation of N-phosphorylated mono-carbon active methylene group. The interaction of sodium derivatives of monoimidates with acid chlorides leads to the formation of the corresponding monoacylated derivatives, for which inhibition of acetyl esterase, esterase hydrolase, cutinase and other enzymes is highly predicted.

Kinetics of direct and water‐mediated tautomerization reactions of nucleobases at low temperatures ⩽200 K

AbstractDetailed chemical kinetic mechanisms for the synthesis of complex organic molecules in the interstellar medium are at an early stage of developement. That such synthesis must take place is well‐known from chemical analysis of sampled asteroids. As molecular complexity increases the number of possible structural isomers also increases with the consequence that the nascent species may adopt a different spatial arrangement, to the lowest energy one. As part of a program of investigations of the hydrogen atom transfer reaction or tautomerization of imidic acid–amide species H‐O=C‐N‐ O=C‐N‐H we have studied the kinetics for a number of nucleobases, namely cytosine, thymine and uracil where a cyclic form of tautomerism (lactim–lactam) is encountered. Together with a fourth, 5‐aza‐uracil (1,3,5‐triazine‐2,4(1H,3H)‐dione), we report on the rates of reaction at low temperatures 50–200 K for both the direct unimolecular process and the similar transformation mediated by an additional water molecule. We show that these tautomerization reactions can be categorized into three classes, and highlight the importance of quantum mechanical tunneling on the rate constants at these low temperatures. We further present some thermochemistry data, such as formation enthalpies, entropies, isobaric heat capacities and enthalpy functions.

Kinetics of the tautomerization of thioimidic acids R−C(SH)NH → R−C(S)NH2: For R = H, F, HO, CN, NC, H2N, HC(O), HC(S), HC≡ C, CH3, CF3, H2C=CH, HOCH2, H2NCH2,CH3C(O), C2H5, (CH3)2CH, C6H5

AbstractThe kinetics of the tautomerization of thio‐imidic acids RC(SH)NH were determined at low (50–300 K) and high (500–1500 K) temperatures as R was varied to encompass mono‐ and diatomic species H, F, HO, NC, CN through H2N, HC(O), HC(S), HC≡ C, H3C, F3C, HOCH2, H2C=CH, CH3C(O), H2NCH2 and including ethyl, isopropyl and phenyl groups. The presence of a labile H‐atom on the R‐group can give rise to an alternative reaction, as in, H3CC(SH)NH → CH2=C(SH)NH2 but these encounter much higher barriers. At the lowest temperatures there is over a million‐fold difference in the rate constants for the fastest, R = H2N, and slowest, R = F, reaction with quantum mechanical tunneling playing a dominant role which is dealt with by canonical transition state and small curvature tunneling theory. The tautomerization of similar imidic acids proceeds at much slower rates due to higher energy barriers to reaction. Additionally basic thermochemical data such as formation enthalpy, entropy, isobaric heat capacity and an enthalpy function are provided for all the species which may be useful training sets for machine‐learning/AI purposes.

Substituent effects in the tautomerization of imidic acids R−C(OH)=NH → R−C(O)NH2: Kinetic implications for the formation of peptide bonds in the interstellar medium

AbstractA number of amides, RC(O)NH2, have been detected spectroscopically in the space between the stars. Naturally the study of how these are formed is an important question on the path of chemical evolution from the elements C, H, N, O, P, … to life because the so‐called peptide‐bond −C(O)−NH− is a key linkage in poly‐amino acids or proteins. Both cyanides and water are abundant in the interstellar medium (ISM) and it has been suggested [J Phys Chem A. 2021;126:924‐939] that these react on water–ice grains, catalyzed by acid H3O+, to form firstly imidic acids R−C≡ N + H2O → RC(OH)NH and subsequently to amides. Here we explore the kinetics in the gas‐phase of the intramolecular tautomerization reaction of the imidic acids for R = H, HO, NC, H2N, HC(O), H3C, HOCH2, H2CCH,H3C(O), H2NCH2, C2H5, and CN, particularly at low temperatures where quantum mechanical small curvature and quantized reactant states tunneling are dominant. The most reactive imidic acid is H2NC(OH)NH which goes on to form urea, one of three known amides in the interstellar medium (ISM), which can self‐react to form cytosine and uracil two canonical nucleobases in RNA. The thermochemistry (, , , ) of the imidic acids and amides is also reported as well as the tautomerization of sulfur and phosphorus analogs HC(SH)NH and HC(OH)PH.

Synthesis and Biological Activity of Esters Based on Cycloalkenedicarboxylic Acids

Previously undescribed esters based on N-substituted imides of cycloaliphatic carboxylic acids have been synthesized in high yields and efficient methods for their preparation have been presented. Toxicological studies of the obtained compounds were carried out using various test objects (Chlorella vulgaris, Allium cepa, Drosophila melanogaster). It was shown that the studied compounds are not active against D. melanogaster, increase the frequency of mutations in C. vulgaris and have the ability to induce chromosomal rearrangements in A. cepa. The synthesized compounds can be used in the development of antitumor drugs.

Spectroscopic and Computational Observation of Glutamine Tautomerization in the Blue Light Sensing Using Flavin Domain Photoreaction.

Blue light sensing using flavin (BLUF) domains constitute a family of flavin-binding photoreceptors of bacteria and eukaryotic algae. BLUF photoactivation proceeds via a light-driven hydrogen-bond switch among flavin adenine dinucleotide (FAD) and glutamine and tyrosine side chains, whereby FAD undergoes electron and proton transfer with tyrosine and is subsequently re-oxidized by a hydrogen back-shuttle in picoseconds, constituting an important model system to understand proton-coupled electron transfer in biology. The specific structure of the hydrogen-bond patterns and the prevalence of glutamine tautomeric states in dark-adapted (DA) and light-activated (LA) states have remained controversial. Here, we present a combined femtosecond stimulated Raman spectroscopy (FSRS), computational chemistry, and site-selective isotope labeling Fourier-transform infrared spectroscopy (FTIR) study of the Slr1694 BLUF domain. FSRS showed distinct vibrational bands from the FADS1 singlet excited state. We observed small but significant shifts in the excited-state vibrational frequency patterns of the DA and LA states, indicating that these frequencies constitute a sensitive probe for the hydrogen-bond arrangement around FAD. Excited-state model calculations utilizing four different realizations of hydrogen bond patterns and glutamine tautomeric states were consistent with a BLUF reaction model that involved glutamine tautomerization to imidic acid, accompanied by a rotation of its side chain. A combined FTIR and double-isotope labeling study, with 13C labeling of FAD and 15N labeling of glutamine, identified the glutamine imidic acid C═N stretch vibration in the LA state and the Gln C═O in the DA state. Hence, our study provides support for glutamine tautomerization and side-chain rotation in the BLUF photoreaction.

An Experimental and Master Equation Investigation of Kinetics of the CH2OO + RCN Reactions (R = H, CH3, C2H5) and Their Atmospheric Relevance.

We have performed direct kinetic measurements of the CH2OO + RCN reactions (R = H, CH3, C2H5) in the temperature range 233-360 K and pressure range 10-250 Torr using time-resolved UV-absorption spectroscopy. We have utilized a new photolytic precursor, chloroiodomethane (CH2ICl), whose photolysis at 193 nm in the presence of O2 produces CH2OO. Observed bimolecular rate coefficients for CH2OO + HCN, CH2OO + CH3CN, and CH2OO + C2H5CN reactions at 296 K are (2.22 ± 0.65) × 10-14 cm3 molecule-1 s-1, (1.02 ± 0.10) × 10-14 cm3 molecule-1 s-1, and (2.55 ± 0.13) × 10-14 cm3 molecule-1 s-1, respectively, suggesting that reaction with CH2OO is a potential atmospheric degradation pathway for nitriles. All the reactions have negligible temperature and pressure dependence in the studied regions. Quantum chemical calculations (ωB97X-D/aug-cc-pVTZ optimization with CCSD(T)-F12a/VDZ-F12 electronic energy correction) of the CH2OO + RCN reactions indicate that the barrierless lowest-energy reaction path leads to a ring closure, resulting in the formation of a 1,2,4-dioxazole compound. Master equation modeling results suggest that following the ring closure, chemical activation in the case of CH2OO + HCN and CH2OO + CH3CN reactions leads to a rapid decomposition of 1,2,4-dioxazole into a CH2O + RNCO pair, or by a rearrangement, into a formyl amide (RC(O)NHC(O)H), followed by decomposition into CO and an imidic acid (RC(NH)OH). The 1,2,4-dioxazole, the CH2O + RNCO pair, and the CO + RC(NH)OH pair are atmospherically significant end products to varying degrees.

Interaction of Isonicotinic Acid Hydrazide with Carboxylic Acid Anhydrides

There has been presented data on the synthesis of monoamides and cyclic imides which are derivatives of isonicotinic acid hydrazide. Cyclic anhydrides of carboxylic acids (succinic, maleic and phthalic) easily react with the hydrazide of isonicotinic acid with cycle opening, forming isonicotinoylhydrazide of dicarboxylic acids, and under more severe conditions the latter are transformed into cyclic acid imides. The structures of the synthesized compounds were studied using 1H- and 13C-NMR spectroscopy, as well as data from twodimensional COSY (1H-1H) and HMQC (1H-13C) spectra. The values of chemical shifts, multiplicity and integral intensity of 1H and 13C signals in one-dimensional NMR spectra were determined. Homo- and heteronuclear interactions confirming the structure of the studied compounds were established using spectra in the COSY (1H-1H) and HMQC (1H-13C) formats. In the approximation of the density functional B3LYP with a base set of 6-31G(d), the enthalpy of the reactions ΔHr in the absence and in the presence of a solvent — isopropanol (self-consistent reaction field method) were calculated quantum-chemically

Decontamination of mustard sulfur and VX by sodium percarbonate complexed with 1-acetylguanidine as a novel activator.

The peroxide-based decontaminants had attracted great attention for degradation of chemical warfare agents (CWAs) because of their high performance, non-corrosive and environmental-friendly merits. Hydrogen peroxide can be activated by some organic activators to enhance the oxidation ability. In this work, a novel formula based on sodium percarbonate (SPC) complexed with 1-acetylguanidine (ACG) was investigated for decontamination of sulfur mustard (HD) and VX as CWAs. In the experimental results, the active species acetyl peroxide imide acid in the formula aqueous solution was detected in situ by Raman and 13C NMR spectroscopy. The optimized conditions of the decontamination formula (SPC/ACG) were suggested that, the molar ratio of active oxygen and activator ([O]/[ACG]) was 1:1 while the pH value of the formula aqueous solution was about 9. To achieve the decontamination percentage over 99%, the molar ratio of active oxygen to CWA ((O)/(CWA)) needed to be at least 3 for HD and 7 for VX. Meanwhile, the degradation products detected by gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS) and ion chromatography (IC) indicated that the oxidation and elimination reactions should have occurred on HD molecule, while the degradation of VX mainly originate from the nucleophilic substitution and oxidation reactions.

The synthesis of N-substituted 4-fluoro-1,8-naphthalimides

Aim. To synthesize 4-fluoro-1,8-naphthalic acid imide and its derivatives substituted in the imide ring.Results and discussion. 4-Fluoro-1,8-naphthalimide was obtained using acenaphthene as the starting material. N-alkyl-4-fluoro-1,8-naphthalimides were synthesized via the phase transfer catalytic alkylation of 4-fluoro-1,8-naphthalimide with haloalkanes. Imidation of 4-fluoro-1,8-naphthalic anhydride with aminoacids resulted in the formation of N-carboxyalkyl-1,8-naphthalimides. These substances can be considered as potential fluorescent labels capable of binding to amino groups of various biological molecules as they contain carboxylic functionality in their structure.Experimental part. The structure of the compounds synthesized was confirmed by FT-IR, 1H NMR and 13C NMR spectroscopy, and mass-spectrometry.Conclusions. It has been shown that 4-fluoro-1,8-naphthalinedicarboxylic acid imide can be obtained following the synthetic route “acenaphthene – 5-fluoroacenaphthene – 4-fluoro-1,8-naphthalic anhydride – 4-fluoro-1,8-naphthalimide”. 4-Fluoro-1,8-naphthalimide can be alkylated by butyl iodide and octyl bromide using tetraalkylammonium salts as a phase transfer catalyst resulted in N-butyl-4-fluoro-1,8-naphthalimide and N-octyl-4-fluoro-1,8-naphthalimide. As a result, N-carboxyalkyl-4-fluoro-1,8-naphthalimides have been obtained for the first time by aminolysis of 4-fluoro-1,8-naphthalic anhydride with glycine, β-alanine and 6-aminocaproic acid.

Synthesis and characterization of cross-linked polymer with sulfonylimide group via UV-radical polymerization for PEMFC

The purpose of this research is to synthesized a new monomer and polymer containing fluorosulfonyl imide acid. A series of polymer electrolyte membranes are prepared via UV-curing technique with polyethylene glycol dimethacrylate (PEGDMA) and the methacryloyl fluorosulfonylimide (MAFSI), which is synthesized by methacrylamide (MAA) and fluorosulfonyl isocyanate (FSO2NCO). The MAFSI monomer and the polymer electrolyte (PMFP) are successfully synthesized and confirmed the structure by 1H NMR and FT-IR. The membranes exhibit high proton conductivity from 79.14 to 110.87 mS/cm, low water uptake from 8.74 to 28.57%, and low dimensional expansion from 6.5 to 30.8% in spite of high IEC values from 3.97 to 5.71 meq./g. In addition, the membranes exhibit good thermal stability up to 150 °C temperatures and the surface morphology of the membrane observed good phase separation between MAFSI and ethylene glycol segments.

Computer‐Aided Design of Crosslinked Polymer Membrane Using Machine Learning and Molecular Dynamics

AbstractThe formation of crosslinking network between polymer chains has significant influence on polymer properties. In particular, the crosslinked structure of ionic networks like proton exchange membrane affects the conductivity performance. To further develop in this area, a framework for polymer membrane design based on the developed quantitative prediction model of the properties of crosslinked polymer is proposed. First, polymers with different crosslinking degrees are constructed by a crosslinking algorithm. Next, molecular dynamics is used to calculate the properties of crosslinked polymers. Then, the quantitative relationship between crosslinked polymer structures and macroscopical properties is developed. Subsequently, computer‐aided polymer design method is integrated with the developed quantitative predict model. The crosslinked polymer design problem is expressed as an optimization problem to obtain the optimal crosslinking degree. Bayesian optimization strategy is used to solve the established optimization model. Finally, two case studies of perfluoro sulfonic acid and perfluoro imide acid design are given to illustrate the application of the proposed polymer design framework.

Atmospheric Oxidation of Imine Derivative of Piperazine Initiated by OH Radical

The cyclic imine 1,2,3,6-tetrahydropyrazine (THPyz) has been observed to be the major atmospheric photo-oxidation product of piperazine, a widely used solvent in carbon-capture technology, yet little is known about its own fate. Very few studies have focused on the atmospheric chemistry of imines in general, despite consistently appearing as major products of amine oxidation. In this work, we explore the reaction mechanism of THPyz oxidation initiated by OH radicals, as well as the fate of the first-generation C-centered (alkyl) and N-centered (aminyl) radical products, with quantum chemistry and theoretical kinetics methods. We predict that the major initial reaction steps involve H-abstraction from a carbon adjacent to the amine nitrogen, leading to subsequent formation of a second imine function via the O2-addition/HO2-elimination pathway. Calculated yields of potentially hazardous products are low but non-negligible. Typically carcinogenic compounds, nitrosamines and nitramines, are expected to have a maximum yield of ∼7% and ∼11%, respectively, under high NOx regimes, considering the uncertainties in the obtained rates. Low yield (1–14%) of an isocyanate is also predicted, formed in a channel following initial H-abstraction from the imine carbon. The aminyl radical formed from OH radical addition to the imine carbon undergoes fast C–C bond scission, leading to an imidic acid. These pathways are minor for OH radical oxidation of THPyz but could be more competitive for other Schiff bases.