A novel photoisomerzation of 1,2‐benzothiazine 1,1‐dioxides to 1,3‐benzothiazine 1,1‐dioxides

Elghamry, Ibrahim; Döpp, D.; Henkel, Gerald

doi:10.1002/jhet.5570440416

Cited by 10 publications

(3 citation statements)

References 34 publications

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“…The photochemistry of monomeric saccharin isolated in solid argon was recently investigated . A search in the literature also yielded some data regarding the photochemistry of some benzisothiazoles in solution, − indicating that the photoreactivity is determined by the structure of the saccharyl ring, the nature of substituents, and the reaction medium. By their turn, tetrazoles are known for their rich photochemistry both in solution and isolated in cryogenic matrices. , Generally, the photochemistry of tetrazole derivatives is influenced by the chemical nature and conformational flexibility of substituents, and when the molecule exhibits tautomerism, tautomer-selective photochemistry may take place. , …”

Section: Introductionmentioning

confidence: 99%

Structure and Photochemistry of a Saccharyl Thiotetrazole

et al. 2014

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The molecular structure and photochemistry of 5-thiosaccharyl-1-methyltetrazole (TSMT) were studied by means of matrix-isolation FTIR spectroscopy, X-ray crystallography, and theoretical calculations. The calculations predicted two conformers of TSMT that differ in energy by more than 15 kJ mol(-1). The infrared spectrum of TSMT isolated in solid argon was fully assigned on the basis of the spectrum calculated (O3LYP/6-311++G(3df,3pd)) for the most stable conformer. In the crystal, TSMT molecules were found to assume the same conformation as for the isolated molecule, with each molecule forming four hydrogen bonds with three neighboring molecules, leading to a network of TSMT oligomers. Upon UV (λ = 265 nm) irradiation of the matrix-isolated TSMT, two photodegradation pathways were observed, both arising from cleavage of the tetrazolyl ring. Pathway a involves cleavage of the N1-N2 and N3-N4 bonds with extrusion of N2, leading to photostable diazirine and thiocarbodiimide derivatives. The photostability of the photoproduced diazirine under the conditions used precluded its rearrangement to the nitrile imine, as reported for 5-phenyltetrazole by Bégué et al. ( J. Am. Chem. Soc. 2012 , 134 , 5339 ). Pathway b involves cleavage of the C5-N1 and N4-N3 bonds, leading to a thiocyanate and methyl azide, the latter undergoing subsequent fragmentation to give CNH.

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Section: Introductionmentioning

confidence: 99%

Structure and Photochemistry of a Saccharyl Thiotetrazole

et al. 2014

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“…Searches were undertaken using the American Chemical Society's Chemical Abstract Service (CAS) Scifinder platform. Only two crystal structures of other sulfones of 2,3dihydro-4H-1,3-benzothiazin-4-ones have been reported (Elghamry et al 2007). No other sulfone of a 2,3-dihydro-4Hpyrido [3,2-e][1,3]thiazin-4-one has been synthesized.…”

Section: Database Surveymentioning

confidence: 99%

Crystal structures of the sulfones of 2,3-diphenyl-2,3-dihydro-4H-1,3-benzothiazin-4-one and 2,3-diphenyl-2,3-dihydro-4H-pyrido[3,2-e][1,3]thiazin-4-one

et al. 2023

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The title sulfones, 2,3-diphenyl-2,3-dihydro-4H-1,3-benzothiazine-1,1,4-trione, C20H15NO3S, and 2,3-diphenyl-2,3-dihydro-4H-pyrido[3,2-e][1,3]thiazine-1,1,4-trione, C19H14N2O3S, crystallize in space group P21/n with two molecules in each of the asymmetric units and have almost identical unit cells and extended structures. In both structures, the thiazine rings exhibit a screw-boat pucker. The intermolecular interactions observed are C—H...O-type hydrogen bonds and parallel partial π–π stacking between the fused aromatic rings (benzo- or pyrido-) of the core of the molecules within each asymmetric unit, and also connecting to molecules with translational periodicity in the a-axis direction in what can be described as columns (two per asymmetric unit) of stacked molecules with alternating chirality. The pendant phenyl groups of both molecules do not participate in aromatic ring interactions.

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“…Alternatively, if conditions for photocleavage of the benzisothiazole moiety are established, photolysis of the tetrazole-saccharyl conjugate will probably produce a set of new compounds, opening ways for the development of synthetic pathways to new scaffolds. Also, to the best of our knowledge the available information related to the photochemistry of bensizothiazoles is still very scarce and all published data report photochemistry in solution [23][24][25][26]. This scenario prompted us to explore the photolysis of the benzisothiazolyl-tetrazole conjugate by matrix isolation FTIR spectroscopy.…”

Section: Introductionmentioning

confidence: 99%