Diazepines. Part V. 2,3-Dihydro-1H-1,4-diazepines

Lloyd, Douglas R.; McDougall, Ronald H.; Marshall, D. R.

doi:10.1039/j39660000780

Cited by 11 publications

(4 citation statements)

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“…17 In the lecture by Lloyd and Marshall 16 many examples of this kind of reactivity are presented. [18][19][20][21][22][23][24] Thus, one of the most important criteria of aromaticity was already fulfilled at that time. In order to have a deeper insight into the problem of relations between different behaviour of chelating systems and aromaticity it is advisable to start from the definition of aromaticity.…”

mentioning

confidence: 95%

Quasi-aromaticity—what does it mean?

et al. 2015

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mentioning

confidence: 95%

Quasi-aromaticity—what does it mean?

et al. 2015

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“…Furthermore, characteristic absorption bands of CvO of ketone and ester in the region 1681 and 1740 cm 21 seen in (1a -k), are absent in the IR spectrum of the 1,3-diketones (2a -k). The traditional approach [17] to the synthesis of 2,3-dihydro-1,4-diazepines is based on the reaction of 1,3-diketones with ethylenediamine in acidic medium. However, a competitive reaction also occurs N.T-not tested.…”

Section: Chemistrymentioning

confidence: 99%

Synthesis and antiproliferative activity of some diaryldiazepines and diarylpyrimidines

Ramajayam

Giridhar

Yadav

et al. 2007

Journal of Enzyme Inhibition and Medicinal Chemistry

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Novel substituted 5,7-diaryl-2,3-dihydro-1,4-diazepines and 4,6-diaryl-2-aminopyrimidines were synthesized and tested for their antiproliferative activity. Title compounds were obtained by cyclocondensation of a substituted flavone with ethylenediamine and guanidine respectively. The cytotoxicity in vitro against various human leukemic cancer cell lines viz., Jurkat, HL60, MOLT3, NCEB-1, K562 was determined.

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“…The 1 H NMR spectrum of 17d· 2H + in concentrated sulfuric acid was incorrectly ascribed to the monocation 17d· H + ,12a evidently because the signal of one of the protons at C‐6 had disappeared in the noise owing to rapid exchange with the solvent. UV spectra of solutions of 17d in sulfuric acid at different concentrations showed the presence of 17d· H + in <50 % acid, but of another species ( 17d· 2H + ) in >70 % acid 29. The protonation of 17d· H + was 50 % complete in 64 % sulfuric acid 30…”

Section: Resultsmentioning

confidence: 98%

2,2′‐Bis‐azonia‐Cope Rearrangements of 2,3‐Homo‐6H‐1,4‐diazepinium Dications

2013

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The condensation of cis‐1,2‐cyclopropanediamines with 1,3‐dicarbonyl compounds and 1,5‐diazapentadienium salts afforded 2,3‐homo‐1H‐1,4‐diazepinium salts, which were protonated by very strong acids to yield 2,3‐homo‐6H‐1,4‐diazepinium dications. As measures of basicity, the mole fractions of water in trifluoromethanesulfonic acid at half‐protonation were determined for 2,3‐homo‐ and 2,3‐dihydro‐1H‐1,4‐diazepinium salts. 2,3‐Homo‐6H‐1,4‐diazepinium dications underwent 2,2′‐bis‐azonia‐Cope rearrangements, as can be inferred from the product structures, or H/D exchange involving the methylene group of the cyclopropane rings. Apparently, in the Cope rearrangement, this group is interchanged with the methylene group in the seven‐membered ring (C‐6), which is susceptible to H/D exchange in strong deuteriated acids. Rapid, degenerate, as well as very slow, strongly biased Cope rearrangements have been uncovered in this way. 1H NMR spectra, recorded at elevated temperatures for a solution of the parent dication in trifluoromethanesulfonic acid, reveal broadening of the interchanging 2‐H, 3‐H and 5‐H, 7‐H signals and eventually the onset of their coalescence. Surprisingly, the estimated free enthalpy of activation is higher (ΔG‡110 °C ≈ 73 ± 2 kJ/mol) than that of 3,4‐homotropilidene (ΔG‡110 °C = 61 kJ/mol), not lower, as would be expected on the basis of the well‐known charge‐acceleration of Cope rearrangements.

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Diazepines. Part V. 2,3-Dihydro-1H-1,4-diazepines

Cited by 11 publications

References 0 publications

Quasi-aromaticity—what does it mean?

Quasi-aromaticity—what does it mean?

Synthesis and antiproliferative activity of some diaryldiazepines and diarylpyrimidines

2,2′‐Bis‐azonia‐Cope Rearrangements of 2,3‐Homo‐6H‐1,4‐diazepinium Dications

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