Ethyl Iodide Research Articles

Origin of Intersystem Crossing in Red-Light Absorbing Bodipy Derivatives: Time-Resolved Transient Optical and Electron Paramagnetic Resonance Spectral Studies with Twisted and Planar Compounds.

We studied the intersystem crossing (ISC) property of red-light absorbing heavy atom-free dihydronaphtho[b]-fused Bodipy derivatives (with phenyl group attached at the lower rim via ethylene bridge, taking constrained geometry, i.e., BDP-1 and the half-oxidized product BDP-2) and dispiroflourene[b]-fused Bodipy (BDP-3) that have a twisted π-conjugated framework. BDP-1 and BDP-3 show strong and sharp absorption bands (i.e., ε = 2.0 × 105 M-1 cm-1 at 639 nm, fwhm ∼491 cm-1 for BDP-3). BDP-1 is significantly twisted (φ = 21.6°), while upon mono-oxidation, BDP-2 becomes nearly planar on the oxidized side (φ = 3.5°). Interestingly, BDP-2 showed efficient ISC (triplet state quantum yield, ΦT = 40%) due to S1/T2 state energy matching. Long-lived triplet excited state was observed (τT = 212 μs in solution and 2.4 ms in polymer matrix), and ISC takes 4.0 ns. Differently, twisted BDP-1 gives weak ISC only 5%, ISC takes 7.7 ns, and the triplet state is populated only with addition of ethyl iodide. Time-resolved electron paramagnetic resonance spectra of BDP-1 revealed the coexistence of two triplet states, with drastically different zero-field splitting D parameters of -2047 MHz and -1370 MHz, respectively, along with varying sublevel population ratios. We demonstrate that the ISC is not necessarily enhanced by torsion of the π-conjugation framework; instead, S1/Tn state energy matching is more efficient to induce ISC even in compounds that have planar molecular structures.

Engineering of halide methyltransferases for synthesis of SAE and its application in biosynthesis of ethyl vanillin

Halide methyltransferase (HMT)-catalyzed synthesis of alkyl donors from S-adenosyl-L-homocysteine (SAH) and haloalkanes is a promising method for biocatalytic alkylation. However, the reported halide methyltransferases show limited catalytic capacity towards unnatural substrates such as ethyl iodide, which limits their application in biocatalytic ethylation. In this work, we performed structure-based directed evolution starting from the wild-type Aspergillus clavatus halide methyltransferase (AcHMT). The best variant, AcHMTM3, was identified with an activity of up to 421.5 mU mg–1 towards ethyl iodide, 38.7-fold higher than that of the wild type AcHMT. Subsequently, molecular dynamics simulations provide structural insights into how mutations improve the catalytic activity towards iodoethane. Finally, AcHMTM3 was utilized in one-pot cascade with the reported O-methyltransferase RnCOMT+Y200L to synthesize ethyl vanillin from 3,4-dihydroxybenzaldehyde (79% conversion). Our work demonstrated the potential of the engineered HMT in further biocatalytic alkylation.

Cover Feature: Theoretical Study of the Hydroxyl‐Radical‐Initiated Degradation Mechanism, Kinetics, and Subsequent Evolution of Methyl and Ethyl Iodides in the Atmosphere (ChemPhysChem 10/2023)

The Cover Feature shows that hydroxyl-radical-initiated degradation and transformation of methyl and ethyl iodides are crucial in the iodine chemical cycle in the marine boundary layer. Their atmospheric degradation would produce atomic iodine, which leads to ozone layer depletion. Cover design by Feng-Yang Bai, Jia-Ming Sun and Co-workers. More information can be found in the Research Article by Feng-Yang Bai, Shuang Ni, Zhen Zhao and co-workers.

Dissociative photoionization studies of ethyl iodide using synchrotron radiation photoionization mass spectrometry and photoelectron imaging

The stepwise dissociative photoionization of ethyl iodide(C2H5I) has been investigated via synchrotron radiation photoionization mass spectrometry and photoelectron imaging spectroscopy. By using VUV synchrotron radiation as excitation source, the photoionization and stepwise dissociative photoionization of C2H5I were observed by tuning the photon energy from 8.5 to 14.0 eV. The ionization energy of C2H5I was measured to be 9.33 ± 0.05 eV, and the appearance energies of C2H5+, C2H4+, C2H3+ were also determined according to the photoionization efficiency spectra. The possible pathways of the stepwise dissociation of C2H5I were determined by combining the experiments with theoretical calculation based on DFT. Finally, the multi-photon ionization process of C2H5I molecule was further studied via intensity-dependent photoelectron imaging spectroscopy.

Theoretical Study of the Hydroxyl-Radical-Initiated Degradation Mechanism, Kinetics, and Subsequent Evolution of Methyl and Ethyl Iodides in the Atmosphere.

The degradation and transformation of iodinated alkanes are crucial in the iodine chemical cycle in the marine boundary layer. In this study, MP2 and CCSD(T) methods were adopted to study the atmospheric transformation mechanism and degradation kinetic properties of CH3 I and CH3 CH2 I mediated by ⋅OH radical. The results show that there are three reaction mechanisms including H-abstraction, I-substitution and I-abstraction. The H-abstraction channel producing ⋅CH2 I and CH3 C ⋅ HI radicals are the main degradation pathways of CH3 I and CH3 CH2 I, respectively. By means of the variational transition state theory and small curvature tunnel correction method, the rate constants and branching ratios of each reaction are calculated in the temperature range of 200-600 K. The results show that the tunneling effect contributes more to the reaction at low temperatures. Theoretical reaction rate constants of CH3 I and CH3 CH2 I with ⋅OH are calculated to be 1.42×10-13 and 4.44×10-13 cm3 molecule-1 s-1 at T=298 K, respectively, which are in good agreement with the experimental values. The atmospheric lifetimes of CH3 I and CH3 CH2 I are evaluated to be 81.51 and 26.07 day, respectively. The subsequent evolution mechanism of ⋅CH2 I and CH3 C ⋅ HI in the presence of O2 , NO and HO2 indicates that HCHO, CH3 CHO, and I-atom are the main transformation end-products. This study provides a theoretical basis for insight into the diurnal conversion and environmental implications of iodinated alkanes.

Pyrolysis of Methyl Formate and the Reaction of Methyl Formate with H Atoms: Shock Tube Experiments and Statistical Rate Theory.

Methyl formate (MF) is the smallest carboxylic ester and currently considered a promising alternative fuel. It can also serve as a model compound to study the combustion chemistry of the ester group, which is a typical structural feature in many biodiesel components. In the present work, the pyrolysis of MF was investigated behind reflected shock waves at temperatures between 1430 and 2070 K at a nominal pressure of 1.1 bar. Both time-resolved hydrogen atom resonance absorption spectroscopy (H-ARAS) and time-resolved time-of-flight mass spectrometry (TOF-MS) were used for species detection. Additionally, the reaction of MF and perdeuterated MF-d4 with H atoms was investigated at temperatures between 1000 and 1300 K at nominal pressures of 0.4 and 1.1 bar with H-ARAS. In the latter experiments, ethyl iodide served as precursor for H atoms. Rate coefficients of seven parallel unimolecular decomposition channels of MF and five parallel reaction channels of the MF + H reaction were calculated from statistical rate theory on the basis of molecular and transition state data from quantum chemical calculations. These calculated rate coefficients were implemented into an MF pyrolysis/oxidation mechanism from the literature, and the experimental concentration-time profiles of H (from ARAS) as well as MF, CH3OH, HCHO, and CO (from TOF-MS) were modeled. It turned out that the literature mechanism, which was originally validated against flow-reactor experiments, ignition delay times, and laminar burning velocities, was generally able to fit also the concentration-time profiles from the shock tube experiments reasonably well. The agreement could still be improved by substituting the original rate coefficients, which were estimated from structure-reactivity relationships, by the values calculated from statistical rate theory in the present work. Details of the channel branching are discussed, and the updated mechanism is given, also in machine-readable form.

Nitrogen Reduction to Ammonia by a Phosphorus-Nitrogen PN 3 P-Mo(V) Nitride Complex: Significant Enhancement via Ligand Postmodification

Nitrogen Reduction to Ammonia by a Phosphorus-Nitrogen PN ³ P-Mo(V) Nitride Complex: Significant Enhancement via Ligand Postmodification

Novel synthesized amide-incorporating copolymeric surfactants based on natural wastes as petro-dispersing agents: Design, synthesis, and characterizations

New cationic copolymeric surfactants were synthesized based on the fatty acid obtained from Juagafa seed wastes, which gave an appropriate yield of lauric acid, which upon esterification and reduction processes was converted to lauryl alcohol. Through the reaction of lauryl alcohol with methacrylic acid (MAA) in the presence of N,N′-dicyclohexylcarbadiimide (DCC), lauryl methacrylate (LMA, as a starting monomer) was obtained. A series of copolymerization feeds between lauryl methacrylate and methacrylic acid in different molar ratios initiated by benzoyl peroxide (BP) were carried out. Also, the obtained data from 1H NMR for the different molar ratios of the poly(LMA-co-MAA) were utilized to estimate the monomer reactivity ratio. The synthesized poly(LMA-co-MAA) with different molar ratio was modified by direct amidation with N,N'-dimethyl-1,3-propanediamine. The amidated copolymers (PA1-5) were quaternized with methyl and ethyl iodides to obtain the corresponding cationic copolymeric surfactants (PSM and PSE). The chemical structures of the prepared compounds were confirmed by FT-IR and 1H NMR analysis. The critical micelle concentrations of the prepared cationic copolymeric surfactants were investigated. Also, the studies of petroleum-collecting and dispersing properties showed that copolymeric surfactants (PSE) have promised effects than PSM ones, especially in sea water and diluted form, and the best molar ratio that gave excellent dispersion of petroleum is PSM-3 and PSE-3.

Branching fraction measurement of the prompt-NO switch reaction NCN + H

The branching fraction ϕ of the prompt-NO switch reaction NCN + H (1), essentially yielding either CH + N2 (1a) or HCN + N (1b), is key for modeling prompt-NO formation in flames. Large discrepancies exist between available experimental data and flame modeling studies on the one hand and high-level theoretical predictions on the other hand, resulting in a factor of 5 uncertainty for ϕ1b at T=1500 K. By simultaneous monitoring of NCN and HCN concentration-time profiles during the reaction NCN + H at temperatures 1200K<T<2000K behind shock waves, ϕ1b has been directly measured for the first time. Thermal decomposition of cyanogen azide (NCN3) and ethyl iodide (C2H5I) served as sources for NCN radicals and H atoms. NCN has been detected by UV laser absorption at 329.130 nm and HCN detection was accomplished by mid-infrared frequency modulation spectroscopy at 3228.049cm−1. Kinetic simulations provided both the total rate constant k1 from the NCN and k1b from the HCN profiles. In order to account for a side reaction of residual BrCN from NCN3 synthesis, a rough estimate for the rate constant of the reaction BrCN + H was inferred from the experiments as well. The measured rate constants for k1 confirm earlier results (Faßheber et al., Phys. Chem. Chem. Phys. 16 (2014) 11647) and k1b follows the Arrhenius expression k1b/(cm3mol−1s−1)=4.2×1014exp(−38.2kJmol−1/RT) with moderate uncertainties of ±(37−49%). The branching fraction increases with temperature, yielding ϕ1b=0.22(±46%) at 1200 K, 0.47(±42%) at 1600 K, and 0.63(±53%) at 2000 K. The corresponding prompt-NO switch temperature of TS=1670K (ϕ1b=0.5) shows that the reaction NCN + H advances toward the Fenimore products HCN + N already at typical temperatures of hydrocarbon/air flames, in stark contrast to the most recent theoretical estimate reporting TS=3235K.

Facile synthesis, larvicidal activity, biological effects, and molecular docking of sulfonamide-incorporating quaternary ammonium iodides as acetylcholinesterase inhibitors against Culex pipiens L

Insecticides participate with a vital role in our lives especially in preventing the spread of human diseases via controlling the dangerous pests. It is a challenge to identify alternatives to the ordinary insecticides with new mode of action to be used for mosquitoes’ control in an environmentally sustainable manner. Using a facile two-step procedure, three novel series of sulfonamide-incorporating quaternary ammonium iodides (3a-i, 4a-i and 5a-i) were synthesized and their chemical structures were successfully characterized. The uncharged sulfonamide intermediates (2a-i) were constructed through simple amidation of the corresponding (hetero)aryl sulfonyl chlorides then the cationic target molecules were formed by quaternizing the tertiary nitrogen with methyl, ethyl, and allyl iodides. The larvicidal activities and biological effects of most synthesized compounds against Culex pipiens L. were extensively investigated and they exhibited good and comparable activities to temephos. Among these hybrids, 4a showed the most potent activity with LC50 = 26.71 ppm. Additionally, the developmental durations of larval and pupal stages were significantly prolonged after treatment with all concentrations of 4h. At high concentration (160 ppm) of 4a and 4b, no adults emerged due to the complete death of pupae, and consequently zero growth index. Moreover, the results of the molecular docking demonstrated that the activities of compounds correlate partially to their binding with acetylcholinesterase (AChE) and it is not the sole parameter for determining the activity.

Marine sediment as a likely source of methyl and ethyl iodides in subpolar and polar seas

The surface ocean is an important source of longer-lived volatile organic iodine compounds, such as methyl and ethyl iodide. However, their production in deep waters is poorly constrained. Here, we combine shipborne seawater and sediment core analyses to investigate the temporal and vertical distribution of methyl and ethyl iodide concentrations in the Bering and Chukchi Seas in July 2017 and 2018, and Funka Bay, Japan, between March 2018 and December 2019. We find the highest methyl and ethyl iodide concentrations in sediment porewaters and at the sediment surface. In Funka Bay, concentrations in the sediment and bottom waters strongly increased following the spring bloom and subsequent settling of phytodetritus to the seafloor. Dark incubation experiments suggest that diatom aggregates are a source of methyl and ethyl iodide to the ambient water. Our findings suggest that phytodetritus at the seafloor is a potential source of volatile organic iodine compounds to the water column in polar and subpolar coastal oceans.

Novel cationic copolymeric surfactants bearing imidazole moiety as petro-dispersing / petro-collecting agents: Synthesis, surface activity and characterization

Novel cationic copolymeric surfactants were designed and synthesized by the quaternization of the copolymer. The synthesized route passes through a two-step reaction, initially including the copolymerization of methacrylic acid (MAA) with 1-vinylimidazole (VIM), followed by the quaternization of the nitrogen atom in imidazole ring present in the obtained poly(VIM-co- MAA) (AI1-5)with different molar ratios, with methyl- and ethyl iodide, respectively to form AISM1-5 and AISE1-5. The chemical structure of the prepared copolymers and cationic polymeric surfactants was confirmed using different spectroscopic techniques such as FT-IR and 1H NMR. The surface-active properties of the synthesized cationic polymeric surfactants were examined. Finema-Ross (F-R) and Kelen-Tudos (K-T) methods were studied from the elemental analysis data, which included the evaluation of the nitrogen content (N%) in prepared copolymers. The monomer reactivity ratios are r1 = 0.157; r2 = 0.966 by F-R and r1 = 0.122; r2 = 0.995) by K-T methods that showed the value of r1r2 is less than the unity (0.152), which indicates the random distribution. The results showed that in sea water, AISE4 is the most distinctive as a petro-dispersant in undiluted form. As well, in diluted and undiluted forms of AISE4, the best petro-collecting capacity is observed on the surface of distilled water.

Efficient synthesis and biological evaluation of some new series of pyridine derivatives: Promising and potent new class of anticancer agents

AbstractIn an attempt to develop potent anticancer agents, we have synthesized some substituted pyridine derivatives. Alkylation of the pyridine‐3‐carbonitrile 1a by chloroacetonitrile or methyl iodide and ethyl iodide produced the O‐alkylated nicotinonitrile derivatives (2–4), respectively. The reaction of nicotinonitrile 1a with acetic anhydride furnished the N‐acetyl derivative 5. In addition, the reaction of 1a with concentrated sulfuric acid yielded compound 6 whereas its reaction with chloroacetone gave the corresponding 2‐alkoxy‐pyridine derivative 7 which then refluxed with sodium methoxide to give compound 8. Furthermore, alkylation of 1a‐c with methyl bromoacetate and ethyl bromoacetate produced the corresponding methyl, ethyl ester derivatives 9, 10a–c, respectively. The reaction of ethyl ester 10c with a solution of sodium hydroxide in ethanol afforded the corresponding acid derivative 11. Hydrazinolysis was carried out by the reaction of ethyl ester 10a,c with hydrazine hydrate to afford the desired acetohydrazide derivative 12a,c which was used as a key intermediate for the synthesis of substituted pyridine derivatives 13–19. Chlorination of 1a with phosphorus oxychloride afforded the 2‐chloro derivative 20 which react with excess of hydrazine hydrate to yield compound 21. All synthesized compounds were characterized using IR, NMR, mass spectra, and elemental analysis. Their cytotoxic activity was evaluated against three different cancer cell lines, including breast (MCF‐7), colon (HCT‐116), and ovarian (SKOV3) cancers as well as human normal cells EA.hy 926 (human endothelial somatic cell hybrid). In general, compounds 3, 4, 5, 9, 12a, 12b, 13, 14, 15, 16, 18, 19, 21 exhibited high cytotoxicity against cancer cell lines. Besides that, the large number of synthesized compounds exhibited moderate anticancer activities.

New Amphiphilic Ionic Liquids for the Demulsification of Water-in-Heavy Crude Oil Emulsion.

This work aimed to use abietic acid (AA), as a widely available natural product, as a precursor for the synthesis of two new amphiphilic ionic liquids (AILs) and apply them as effective demulsifiers for water-in-crude oil (W/O) emulsions. AA was esterified using tetraethylene glycol (TEG) in the presence of p-toluene sulfonic acid (PTSA) as a catalyst obtaining the corresponding ester (AATG). AATG was reacted with 1-vinylimidazole (VIM) throughout the Diels–Alder reaction, forming the corresponding adduct (ATI). Following this, ATI was quaternized using alkyl iodides, ethyl iodide (EI), and hexyl iodide (HI) to obtain the corresponding AILs, ATEI-IL, and ATHI-IL, respectively. The chemical structure, surface activity, thermal stability, and relative solubility number (RSN) were investigated using different techniques. The efficiency of ATEI-IL and ATHI-IL to demulsify W/O emulsions in different crude oil: brine volumetric ratios were evaluated. ATEI-IL and ATHI-IL achieved promising results as demulsifiers. Their demulsification efficiency increased as the brine ratios decreased where their efficiency reached 100% at the crude oil: brine ratio (90:10), even at low concentrations.

Nitrophenyl-Group-Containing Heterocycles. I. Synthesis, Characterization, Crystal Structure, Anticancer Activity, and Antioxidant Properties of Some New 5,6,7,8-Tetrahydroisoquinolines Bearing 3(4)-Nitrophenyl Group.

Regioselective cyclocondensation of 2,4-diacetyl-5-hydroxy-5-methyl-3-(3-nitrophenyl/4-nitrophenyl)cyclohexanones 1a,b with cyanothioacetamide afforded the corresponding 7-acetyl-4-cyano-1,6-dimethyl-6-hydroxy-8-(3- and -4-nitrophenyl)-5,6,7,8-tetrahydrosoquinoline-3(2H)-thiones 2a,b. Reaction of compounds 2a,b with ethyl iodide, 2-chloroacetamide (4a), or its N-aryl derivatives 4b–e in the presence of sodium acetate trihydrate gave 3-ethylthio-5,6,7,8-tetrahydroisoquinoline 3 and (5,6,7,8-tetrahydroisoquinolin-3-ylthio)acetamides 5a–i, respectively. Cyclization of compounds 5b–d,f,g into their isomeric 1-amino-6,7,8,9-tetrahydrothieno[2,3-c]isoquinoline-2-carboxamides 6b–d,f,g was achieved by heating in ethanol containing a catalytic amount of sodium carbonate. Structures of all synthesized compounds were characterized on the basis of their elemental analyses and spectroscopic data. The crystal structure of 5,6,7,8-tetrahydroisoquinoline 5d was determined by X-ray diffraction analysis. In addition, the biological evaluation of some synthesized compounds as anticancer agents was performed, and only six compounds showed moderate to strong activity against PACA2 (pancreatic cancer cell line) and A549 (lung carcinoma cell line). Moreover, the antioxidant properties of most synthesized compounds were examined. The results revealed high antioxidant activity for the most tested compounds.

Hydrogen bonding as a probe of electron density Variations: Substituted pyridines

An approach for experimental assessment of the trend of variations of the electron density at the basic center for series of substituted pyridines, based on the shifts of infrared O-H stretching frequencies of selected proton-donating species upon hydrogen bonding with the pyridine derivatives [Δν(OH)exp], is validated. Strong correspondence between theoretically evaluated atomic charges (Hirshfeld, CM5) and the electrostatic potential for the pyridine nitrogen in the monomeric derivatives and spectroscopic data for the Δν(OH)exp shifts (ref. 7) is established. The spectroscopic shifts correlate also excellently with the rate constants for quaternization of substituted pyridines with ethyl iodide. The ωB97X-D/6–311++G(3df,2pd) method is used in the computations, conducted in the present research.

A novel validated simple derivatization liquid chromatographic method with diode array detection for the simultaneous determination of mancozeb, azoxystrobin and difenoconazole in pesticide dosage form.

A novel, rapid and simple reverse-phase high performance liquid chromatography (RP-HPLC) method for the simultaneous determination of three pesticides - mancozeb, azoxystrobin and difenoconazole by derivatization with ethyl iodide is presented. Analysis was performed on a C18 column (Agilent Eclipse plus, 150 mm × 4.6 mm; 5 μ) with the mobile phase consisting of acetonitrile + methanol (90 + 10 v/v) - water (0.1% v/v trifluoroacetic acid) (60 : 40, v/v) pumped isocratically at a flow rate of 1.0 mL min-1 and detection wavelength of 205 nm and 272 nm. The factors affecting the derivatization reaction and separation conditions were carefully evaluated and optimized. The method was linear over the concentration range of 3.50 mg L-1 to 31.48 mg L-1 for mancozeb, 0.32 mg L-1 to 2.85 mg L-1 for azoxystrobin and 0.32 mg L-1 to 2.89 mg L-1 for difenoconazole. The new method was successfully applied for the analysis of mancozeb, azoxystrobin and difenoconazole in the pesticide formulation with range recoveries of 99.46% to 100.76%, 99.07% to 101.09% and 98.59% to 101.59%, respectively. The present method is suitable and favorable for the simultaneous separation and analysis of tertiary mixture analytes on account of its sensitivity, rapidity and cost-effectiveness. In addition, it could have excellent application prospects for the simultaneous determination of all three pesticides in other formulated products.

Synthesis, characterization, and photophysical properties of some new thieno[2,3‐b]pyridines bearing phenylethenyl moiety

Abstract5‐Acetyl‐3‐cyano‐6‐methyl‐4‐(2‐phenylethenyl)pyridine‐2(1H)‐thione (2) was synthesized by interaction of cinnamylidene‐2‐cyanothioacetamide 1 and acetylacetone or via one‐pot reaction of E‐cinnamaldehyde, 2‐cyanothioacetamide, and acetylacetone. Reaction of 2 with ethyl iodide (3a) or N‐chloroacetyl derivative of aromatic amines 3b–e in boiling ethanol containing sodium ethoxide gave the corresponding thioether 4a and 5‐acetyl‐3‐amino‐2‐(N‐arylcarbamoyl)‐6‐methyl‐4‐(2‐phenylethenyl)thieno[2,3‐b]pyridines 5b–e, respectively. Compound 5e was reacted with 2,5‐dimethoxytetrahydrofuran or triethyl orthoformate to furnish pyrrolylthienopyyridine 6 or pyrdiothienopyrimidinone 7, respectively. The photophysical properties of 5b, 5c, 5e, and 7 were fully studied and the obtained results included herein. The fluorescence data confirmed that compounds 5b, 5c, 5e, and 7 exhibit aggregation‐induced emission behavior with high absolute quantum yields.

Comparison of 2D crystals formed by dissociative adsorption of fluorinated and nonfluorinated alkyl iodides on Cu(111)

We report the comparison of a series of 2D molecular crystals formed from the intermediates of the dehalogenation reaction of iodoethane versus various fluorinated iodoalkanes on Cu(111). High-resolution scanning tunneling microscopy enables us to distinguish the alkyl groups from the iodine atoms, and we find that the ethyl groups and iodine atoms formed from the dissociation of ethyl iodide are well mixed. However, fluorination of the alkyl tail changes this behavior and leads to local segregation of the two species on the surface. We postulate that the low-polarizability and relatively large dipole moment of the fluorinated species drive the ordered assemblies of the fluorinated alkyl species on the surface and discuss this in the context of how solvophobicity can drive the clustering of fluorinated groups and, hence, phase separation.

DFT Calculation, Hirshfeld Analysis and X-Ray Crystal Structure of Some Synthesized N-alkylated(S-alkylated)-[1,2,4]triazolo[1,5-a]quinazolines

The present work aimed to synthesize 2-methylthio-triazoloquinazoline derivatives and study their X-ray, NMR, DFT and Hirshfeld characteristics. The cyclocondensation of dimethyl-N-cyanodithiocarbonate with 2-hydrazinobenzoic acid hydrochloride resulted in an intermediate, 2-methylthio-[1,2,4]triazolo[1,5-a]quinazolin-5-one (A), which upon treatment with phosphorus pentasulfide, transformed into the 2-methylthio-[1,2,4]triazolo[1,5-a]quinazolin-5-thione (B). Reaction of 2-methylthio-triazoloquinazolines (A&amp;B) with alkyl halides (allyl bromide and ethyl iodide) in basic medium afforded 4-allyl-2-methylthio-[1,2,4]triazolo[1,5-a]quinazolin-5-one (1; N-alkylated) and 5-ethylthio-2-methylthio-[1,2,4]triazolo[1,5-a]quinazoline (2; S-alkylated), respectively. Their molecular and supramolecular structures were presented. Unambiguously, the molecular structures of 1 and 2 were confirmed via NMR and single-crystal X-ray diffraction. The resulting findings confirmed the structures of 1 and 2 and determined their crystalized system (monoclinic system; P21/n space group). Hirshfeld analysis of 1 revealed the importance of the significantly short O···H (6.7%), S···S (1.2%) and C···C (2.8%); however, the short H···H (42.6%), S···H (16.3%) and C···C (4.3%) were showed in 2 by intermolecular interactions in the molecular packing. The 1,2,4-triazoloquinzolines (1&amp;2) were anticipated to be relatively polar compounds with net dipole moments of 2.9284 and 4.2127 Debye, respectively. The molecular electrostatic potential, atomic charge distribution maps and reactivity descriptors for 1 and 2 were also determined. The calculated nuclear magnetic resonance spectra of the targets 1 and 2 were well correlated with the experimental data.