Darstellung und reaktives Verhalten von 2‐Arylamino‐selenazolen

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

“…The stability of the acetylated compounds in solution seems to be higher than that of the parent compounds: the amines turn yellow and red in solution over time, whereas solutions of the acetylated derivatives remain unchanged for several days. Bulka reported that 2-arylamino-1,3-selenazoles react with NaNO 2 in acetic acid at room temperature to give the corresponding N-nitrosamines [8]. When we reproduced this reaction, we isolated a red-orange product, in which the resonances of both the amine proton and the proton at position 5 of the heterocycle were missing in the 1 H NMR spectrum.…”

“…In the solidstate the molecules from an infinite zig-zag chain through N-H-Se hydrogen bonds between selenium and NH2 groups from neighboring molecules (Figure 3b). The 2-arylamino-1,3-selenazoles were subsequently obtained from the cyclocondensation reaction of these arylselenoureas with various 2-haloketones in the presence of Et3N (Scheme 2) [8,9,27]. The products and their yields are collected in Table 1.…”

“…Some of the compounds were previously reported, however, characterization was restricted to melting points and elemental analysis. Thus, all of the The 2-arylamino-1,3-selenazoles were subsequently obtained from the cyclocondensation reaction of these arylselenoureas with various 2-haloketones in the presence of Et 3 N (Scheme 2) [8,9,27]. The products and their yields are collected in Table 1.…”

“…In the late 1960s the group of Bulka published two papers (in German) on the preparation of 2-arylamino-1,3-selenazoles and their reactivity [8,9]. The free amines could be acetylated in acetic anhydride and the reaction with NaNO 2 in acetic acid (in situ formed nitrous acid) gave yellow products, which were (erroneously) proposed to be the corresponding N-nitrosamines (Scheme 1); functionalization at position 5 was explicitly excluded [8]. However, the reaction with nitroso anilines gave C5-substituted azomethines (Scheme 1) [8].…”

“…Molecules 2021, 26, 7695 2 of 25 free amines could be acetylated in acetic anhydride and the reaction with NaNO2 in acetic acid (in situ formed nitrous acid) gave yellow products, which were (erroneously) proposed to be the corresponding N-nitrosamines (Scheme 1); functionalization at position 5 was explicitly excluded [8]. However, the reaction with nitroso anilines gave C5-substituted azomethines (Scheme 1) [8]. Phenyldiazonium chloride reacted with the selenazoles to give the C5-azo product, confirming the results of Haginiwa.…”