2-phenyl-1,3,4-thiadiazol-2-ines

Зеленин, K. Н.; Khrustalev, V. A.; Алексеев, В. В.; Sharbatyan, P. A.; Lebedev, A. T.

doi:10.1007/bf00568942

Cited by 5 publications

(5 citation statements)

References 9 publications

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“…The tendency to cyclization of thiobenzoylhydrazones and mercaptoacetylhydrazones into derivatives of 1,3,4-thiadiazoline and 1,3,4-thiadiazin-5-оne, respectively, is a general property of these classes of compounds. 8,9 To confirm the presence of cyclic forms, in addition to the isoxazolidine ring, the spectroscopic characteristics of compounds 3-5 known in the literature [8][9][10] were studied. These compounds are models for the corresponding forms B, C, and D of the studied compounds (Scheme 3).…”

Section: Resultsmentioning

confidence: 99%

“…Thus, the signal of the sp 3 -C-5 atom at 80 ppm has been observed in the carbon spectrum of 2-phenyl-5,5-dimethyl-1,3,4-∆2-thiadiazoline 3. 9 Sixmembered rings, unlike five-membered rings, are characterized by an upfield shift of signals of the hemiacetal carbon atoms by 10-15 ppm. Therefore, for the signals of the C-2 atom in the 1,3,4-thiadiazine ring of compound 4 a chemical shift will be observed at 70 ppm.…”

Section: Resultsmentioning

confidence: 99%

“…This was shown by taking spectra in a large set of solvents with variation of temperature and time parameters over a wide range. Thus, even in trifluoroacetic acid solution which is known 9 to favor cyclization into a 1,3,4-thiadiazoline ring, compound 2c also has a linear hydrazone structure B.…”

Section: Methodsmentioning

confidence: 99%

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Synthesis and structure of 5-acylhydrazine-3,3,5-trimethylisoxazolidines

Еrshov¹,

Добродумов²,

Грибанов³

2004

Arkivoc

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Synthesis and structure of 5-acylhydrazine-3,3,5-trimethylisoxazolidines

Еrshov¹,

Добродумов²,

Грибанов³

2004

Arkivoc

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“…Positive ions appeared to be useful for studying chemical reactions catalyzed by acids [ 18 ], and negative ions were applied to study solution reactions triggered by bases [ 19 , 20 ]. Mass spectrometry also enabled differentiation between the linear or cyclic structures of triazoles [ 19 ] and thiadiazoles [ 21 ]. Moreover, almost all classic organic chemistry rearrangement reactions were found to take place in the ion source of a mass spectrometer [ 15 ].…”

Section: Introductionmentioning

confidence: 99%

Differentiation between Isomeric 4,5-Functionalized 1,2,3-Thiadiazoles and 1,2,3-Triazoles by ESI-HRMS and IR Ion Spectroscopy

et al. 2023

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A large variety of 1,2,3-thiadiazoles and 1,2,3-triazoles are used extensively in modern pure and applied organic chemistry as important structural blocks of numerous valuable products. Creation of new methods of synthesis of these isomeric compounds requires the development of reliable analytical tools to reveal the structural characteristics of these novel compounds, which are able to distinguish between isomers. Mass spectrometry (MS) is a clear choice for this task due to its selectivity, sensitivity, informational capacity, and reliability. Here, the application of electrospray ionization (ESI) with ion detection in positive and negative modes was demonstrated to be useful in structural studies. Additionally, interconversion of isomeric 4,5-functionalized 1,2,3-triazoles and 1,2,3-thiadiazoles was demonstrated. Application of accurate mass measurements and tandem mass spectrometry in MS2 and MS3 modes indicated the occurrence of gas-phase rearrangement of 1,2,3-triazoles into 1,2,3-thiadiazoles under (+)ESI-MS/MS conditions, independent of the nature of substituents, in line with the reaction in the condensed phase. Infrared multiple photon dissociation (IRMPD) spectroscopy enabled the establishment of structures of some of the most crucial common fragment ions, including [M+H-N2]+ and [M+H-N2-RSO2]+ species. The (−)ESI-MS/MS experiments were significantly more informative for the sulfonyl alkyl derivatives compared to the sulfonyl aryl ones. However, there was insufficient evidence to confirm the solution-phase transformation of 1,2,3-thiadiazoles into the corresponding 1,2,3-triazoles.

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“…Mass spectrometry (MS) has been shown to be a valuable and rapid method to conduct monomolecular reactions in the gas phase 8,9 . It allows structures of heterocyclic compounds to be elucidated 10 and these gas‐phase reactions often demonstrate similarities to reactions in solution, sometimes predicting the directions and yields of chemical reactions in solution 10–13 . Positive ions in electron ionization, chemical ionization, and electrospray ionization allow 8,9 the study of monomolecular reactions carried out in solution and initiated by thermolysis, photolysis or acid‐catalysis 8,9 .…”

Section: Introductionmentioning

confidence: 99%

Gas‐phase study of the stability of α‐substituted cyclic amino nitriles under electron ionization and electrospray ionization and fragmentation peculiarities of cyclic ketimines

Sosnova

Mazur

Lebedev

2020

Rapid Comm Mass Spectrometry

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Rationale: α-Substituted cyclic amino nitriles show different reactivity and stability in solution depending on their ring size. Mass-spectrometric modeling of the reactions, which normally take place in solution, may shed light on the nature of the studied compounds and explain some observations. Methods:The stability of the nitriles in an acidic solution was studied by adding glacial acetic acid. Gas-phase modelling was conducted by gas chromatography/mass spectrometry (GC/MS) with electron ionization mass spectrometry and direct inlet electrospray ionization. QqQ and Orbitrap analyzers were used to carry out tandem mass spectrometry (MS/MS) experiments. Results:The obtained data show that the elimination of HCN from α-substituted cyclic amino nitriles occurs in the same way for an acidic solution, thermolysis and electrospray ionization. According to GC, the most stable were N-formylated nitriles compared with N-benzylated or N-unsubstituted ones. Electrospray ionization demonstrated its advantages for the routine identification of cyclic amino nitriles due to milder conditions than in electron ionization. Fragmentations of cyclic ketimines, formed from N-unsubstituted amino nitriles, are discussed in particular. Conclusions: Similarities in the behavior of the α-substituted cyclic amino nitriles under electron ionization, electrospray ionization, thermolysis and reaction in solution under acidic catalysis were discovered and confirmed by MS/MS experiments. Fragmentation schemes of the studied nitriles and corresponding imines are proposed.

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2-phenyl-1,3,4-thiadiazol-2-ines

Cited by 5 publications

References 9 publications

Synthesis and structure of 5-acylhydrazine-3,3,5-trimethylisoxazolidines

Synthesis and structure of 5-acylhydrazine-3,3,5-trimethylisoxazolidines

Differentiation between Isomeric 4,5-Functionalized 1,2,3-Thiadiazoles and 1,2,3-Triazoles by ESI-HRMS and IR Ion Spectroscopy

Gas‐phase study of the stability of α‐substituted cyclic amino nitriles under electron ionization and electrospray ionization and fragmentation peculiarities of cyclic ketimines

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