Synthesis of the thiophene series 1,3-diselenanes

Fragmentation of pyrazolecarbaldehyde thio- and dithioacetals under electron impact and chemical ionization

“…The main fragmentation pathway of [M] + · and [M + H] + is cleavage of the eight-membered heteroring with elimination of C 4 H 9 OS · and formation of ions G and H (Scheme 7). This pattern is typical of 1,3-diselenanes of the thiophene series [10] but is different from the decomposition of 1,4,6-oxadithiocane which mainly loses H 2 S 2 species (Scheme 8) [11]. It is known that elimination of HS · and HS 2 · radicals is characteristic of fragmentation of all 2-aryl-1,3-dithianes [8].…”

“…Moreover, these compounds may equally be regarded as functionally substituted pyrazoles and dithioacetals derived from 2-sulfanylethanol and the corresponding pyrazolecarbaldehyde. Therefore, their fragmentation under electron DOI: 10.1134/S1070428011120116 X = Me (a), Pr (b), i-Pr (c), CH 2 =CHCH 2 (d), PhCH 2 (e). (5), 82 (7), 81 (7), 80 (7), 79 (4), 78 (12), 77 (4), 69 (3), 68 (5), 67 (8), 66 (7), 65 (8) impact can follow pathways typical of both classes of compounds or take a quite different pathway.…”

Selenoacetalyzation of 4‐Formylpyrazoles in the Presence of Trimethylchlorosilane

“…Heteryl‐1,3‐diselenanes were unknown until our investigations. Earlier, we synthesized 2‐(1,3‐diselenan‐2‐yl)thiophenes in 12%–57% yields from propane‐1,3‐diselenol and thiophene carbaldehydes . It was found that even under mild conditions [–5 to 5°С, trimethylchlorosilane (ТМSСl) as a catalyst], selenoacetalyzation was accompanied by the formation of oligomeric products.…”

First example of the synthesis of bis(2-hydroxyethyl)dithioacetals from nitrobenzaldehydes and mercaptoethanol in the presence of methylchlorosilanes

“…[6][7][8]. We formerly obtained open-chain dithio-and diselenoacetals of thiophenecarbaldehydes with the use of trimethylchlorosilane [9][10][11].…”