Old Selenium Heterocycles Revisited: Synthesis, Spectroscopic, and Structural Characterization ofN‐Acyl‐1,3‐selenazol‐2(3H)‐imines and 5‐Acyl‐1,3‐selenazol‐2‐amines from Acylselenourea Derivatives

Abstract

A series of five‐membered selenium heterocycles was prepared from the reaction of various selenoureas and phenacyl bromides. In the case of 1‐acyl‐3‐arylselenoureas N‐acyl‐1,3‐selenazol‐2(3H)‐imines are formed, whereas the analogous reaction with 3,3‐disubstituted 1‐acylselenoureas affords 5‐acyl‐1,3‐selenazol‐2‐amines. The compounds were characterized by NMR spectroscopy and mass spectrometry. In addition, the proposed structures were unambiguously confirmed by X‐ray diffraction studies.

Synthesis, Reactivity and Antimicrobial Activity of a Series of 2-Arylamino-1,3-selenazoles

“…Despite of this, we managed to obtain single crystals suitable for Xray diffraction of 1c (Figure 1). We previously reported some aspects of the chemistry of aryl-selenazoles derived from acylselenoureas, as well as the biological activity of various selenium-containing metal complexes [13][14][15]. Selenium-containing compounds in general experienced a recent renaissance, especially due to their promising medical applications [16,17].…”

“…1 H-NMR (400 MHz, DMSO-d 6 ) δ = 2.19 (d, J = 1.1 Hz, 3 H, Me), 6.85 (s, 2 J H-Se = 50 Hz, 1 H, CH), 6.95 (tt, J = 7.5, 1,1 Hz, 1 H, p-Ph), 7.27-7.32 (m, 2 H, m-Ph), 7.63 (d, J = 7.9 Hz, 2 H, o-Ph), 10.18 (s, 1 H, NH). 13…”

“…1 H-NMR (400 MHz, DMSO-d 6 ) δ [ppm] = 2.17 (d, J = 1.0 Hz, 3H, Me), 2.24 (s, 3H, C 6 H 4 -Me), 6.79 (s, 1H, CH), 7.10 (d, J = 8.2 Hz, 2H, C 6 H 4 ), 7.49 (d, J = 8.4 Hz, C 6 H 5 ), 10.06 (s, 1H, NH). 13…”

“…1 H-NMR (400 MHz, DMSO-d 6 ) δ [ppm] = 3.74 (s, 3H, OMe), 6.95 (d, J = 9.1 Hz, 2H, C 6 H 4 ), 7.29 (t, J = 7.3 Hz, 1H, p-Ph), 7.39 (t, J = 7.6 Hz, 2H, m-Ph), 7.68 (m, 3H, CH, C 6 H 4 ), 7.91 (d, J = 9.9 Hz, 2H, o-Ph), 10.17 (s, 1H, NH). 13 This was prepared as described above using 4-MeOC 6 H 4 NHC(Se)NH 2 (0.200 g, 0.93 mmol) and 2-bromo-4 -methylacetophenone (0.195 g, 0.91 mmol). The product was obtained as a colorless solid in 58% yield (0.182 g).…”

“…1 H-NMR (400 MHz, CDCl 3 ) δ [ppm] = 2.37 (s, 3H, Me), 3.83 (s, 3H, OMe), 6.90 (d, J = 9.0 Hz, 2H, MeOC 6 H 4 ), 7.17 (d, J = 7.9 Hz, 2H, MeC 6 H 4 ), 7.22 (s, 1H, CH), 7.29 (d, J = 9.0 Hz, 2H, MeOC 6 H 4 ), 7.72 (d, J = 8.1 Hz, 2H, MeC 6 H 4 ). 13 This was prepared as described above using 4-MeOC 6 H 4 NHC(Se)NH 2 (0.203 g, 0.95 mmol) and 2-bromo-4 -phenylacetophenone (0.291 g, 1.06 mmol). The product was obtained as a beige solid in 68% yield (0.260 g).…”