Сообщение
Arkadii_Tarasevych » Вс ноя 20, 2011 11:13 pm
По поводу первого и второго: скайфайндер именно такие соединения не нашёл. Зато есть похожее, когда один из тиофенилов замещён трифенилметилом:
Synthesis of pyrylium salts and pyridines with heterocyclic substituents By Dorofeenko, G. N.; Korol'chenko, G. A.; Krivun, S. V. From Khimiya Geterotsiklicheskikh Soedinenii (1965), (6), 817-21. Language: Russian, Database: CAPLUS
Several pyrylium salts (I) with heterocyclic substituents were obtained by the cyclization of 1,5-diketones (II) in HOAc using triphenylmethyl perchlorate. II were obtained by alk. condensation of aromatic and heterocyclic aldehydes with Me ketones in EtOH. II contg. thiophene, pyrrole, or selenophene residues in the meso position on cyclization gave a mixt. of 2 substances, which could be sepd. in only 1 example. I on shaking with aq. ammonia were readily connected into pyridines (III) when heterocyclic constituents were on the ring. The structure of the obtained compds. was supported by their ir spectra. The following III were obtained (given R, R', and m.p.): Ph, 1-methyl-3-indolyl, 144.5°; Ph, 1-methyl-2-pyrrolyl, 138°; Ph, 5-triphenylmethyl-2-thienyl, 212.5°; 2-thienyl, Ph, 116.5°; 2-furyl-, Ph, 128°.
Третье с анионом BF4(-) найдено:
Reactivity of carbanions of Fischer-type carbene complexes with pyrylium salts. Synthesis and characterization of new γ-methylenepyran carbene complexes via an addition-oxidation-deprotonation process By Caro, Bertrand; Le Poul, Pascal; Robin-Le Guen, Francoise; Saillard, Jean-Yves; Kahlal, Samia; Moinet, Claude; Le Poul, Nicolas; Vaissermann, Jacqueline From Tetrahedron (2002), 58(37), 7519-7530. Language: English, Database: CAPLUS
The condensation reaction between γ-unsubstituted pyrylium salts and carbanions of Fischer-type carbene complexes gave new γ-methylenepyran carbene complexes in 5-85% yields. NMR data, single crystal x-ray anal., and DFT calcns. suggest that these complexes have a partial pyrylium character due to the π electron-accepting ability of the carbenic fragment and to the electron-releasing properties of the methylenepyran part.
