New Synthetic Method for 1,3,4,5-Tetraaryl-2-thioxo-(or -oxo)-2,3-dihydroimidazoles

Mehrotra, K. N.; Singh, G. B.

doi:10.1055/s-1980-29297

Cited by 15 publications

(8 citation statements)

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“…After prolonged reaction times or after slight warming of the reaction mixture including 9 c , only the known aromatic compound 18 c 31 was found with 87 % NMR yield based on dibromide 15 c . Although we prepared the known heterocycles 10 c 32 and 11 c 33 for comparison, they could not be detected as thermal secondary products of 9 c . This should exclude the postulated9 bi‐2 H ‐azirin‐2‐yl 9 c being intermediate during the transformation 7 c → 10 c + 11 c assuming that the presence of the generated lithium chloride did not change the thermal successive reactions of 9 c dramatically.…”

Section: Resultsmentioning

confidence: 95%

“…Tetraphenylpyridazine 18 c (87 %) was obtained as the stable final product and identified by comparing its 1 H NMR and 13 C NMR data to those of an independently prepared31 sample. These data can be unequivocally distinguished from those of 10 c 32 and 11 c ,33 which were also synthesized for control experiments including photostability. The azirine 17 c as well as bi‐2 H ‐azirin‐2‐yls meso ‐ and rac ‐ 9 c could be observed as intermediates by NMR spectroscopy.…”

Section: Methodsmentioning

confidence: 89%

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Experimental and Theoretical Characterization of the Valence Isomerization of Bi‐2H‐azirin‐2‐yls to Diazabenzenes

Banert

Herges

Heß

et al. 2006

Chemistry A European J

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3,4-diazidocyclobutenes 16 were prepared from the corresponding dihalides. Some of these diazides, such as parent compound 16 d and phenyl-substituted derivatives 16 c,f, underwent spontaneous stereoselective electrocyclic ring opening below room temperature, whereas the tetraalkyl derivatives of 16 had to be heated to force the same reaction. In most cases, the resulting 1,4-diazidobuta-1,3-dienes 8 were isolated to study their photochemical transformation into bi-2H-azirin-2-yls 9 via intermediate mono-azirines 17. Except for starting materials with a low number of substituents such as 9 d and 9 f, title compounds 9 underwent a thermal valence isomerization which led exclusively to pyridazines 18 at surprisingly low temperatures. Based on quantum-chemical calculations for the parent bi-2H-azirinyl-2-yl 9 d at the UB3LYP/6-31+G(d) and MR-MP2/TZV(2df,2p) levels, the valence isomerization process is best explained by simultaneous homolytic cleavage of both C--N single bonds of 9 to generate energetically favorable N,N' diradicals 26, which cyclize to 18. The theoretical studies indicate also that one stereoisomer of 9, namely, the rac compound, should undergo valence isomerization more easily than the other, which is in conformity with different rates of these rearrangement reactions found experimentally. For the tetramethyl-bi-2H-azirin-2-yls 9 g, which are better models for the experimentally studied compounds, simultaneous homolytic cleavage of both C--N single bonds is also predicted by the calculations, although the intermediate diradicals 26 g are significantly higher in energy than those of the parent system 9 d.

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Section: Resultsmentioning

confidence: 95%

Section: Methodsmentioning

confidence: 89%

Experimental and Theoretical Characterization of the Valence Isomerization of Bi‐2H‐azirin‐2‐yls to Diazabenzenes

Banert

Herges

Heß

et al. 2006

Chemistry A European J

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“…During the synthesis of a large series of chiral -diimines by condensation of -diketones with chiral primary amines following a known procedure (Mehrotra & Singh, 1980), we obtained the title compound, (I), as an unexpected by-product (see Experimental).…”

Section: Commentmentioning

confidence: 99%

2-Methyl-1,4,5-triphenyl-1H-imidazole

et al. 2002

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“…Several methods are available for the synthesis of substituted imidazole‐2‐thiones in the literature . McCombie et al .…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, Mehrotra et al . have prepared these compounds by the reaction of 1,2‐diarylethan‐1,2‐dione with aniline and carbon disulfide. Different derivatives of imidazole‐2‐thiones have also been prepared by the reaction of o‐phenylenediamine with carbon disulfide or thiocarbonyldiimidazole .…”

Section: Introductionmentioning

confidence: 99%

Synthetic Approaches towards the Sulfonamide Substituted‐1,5‐Diarylimidazole‐2‐thiones as Selective Cyclooxygense‐2 inhibitors

Navidpour

Amini

Miri

et al. 2013

Journal of Heterocyclic Chem

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A new series of sulfonamide substituted 1,5‐diarylimidazole, possessing C‐2 alkylthio moiety, were synthesized for their cyclooxygense‐2 (COX‐2) inhibitory activity starting from condensation of N,N‐dibenzylaminosulfonylphenacylamine hydrochloride (2) and corresponding isothiocyanate in the presence of Et3N, followed by alkylation in the basic medium. In concomitant with these intermediates, 2‐arylamino‐5‐arylthiazole derivatives 5 were also produced. The ratio of these two products was variable with different isothiocyanates. Final debenzylation was achieved using concentrated sulfuric acid to give the title sulfonamides 8.

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New Synthetic Method for 1,3,4,5-Tetraaryl-2-thioxo-(or -oxo)-2,3-dihydroimidazoles

Cited by 15 publications

References 0 publications

Experimental and Theoretical Characterization of the Valence Isomerization of Bi‐2H‐azirin‐2‐yls to Diazabenzenes

Experimental and Theoretical Characterization of the Valence Isomerization of Bi‐2H‐azirin‐2‐yls to Diazabenzenes

2-Methyl-1,4,5-triphenyl-1H-imidazole

Synthetic Approaches towards the Sulfonamide Substituted‐1,5‐Diarylimidazole‐2‐thiones as Selective Cyclooxygense‐2 inhibitors

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