Вид документа : Статья из журнала Шифр издания : 54/S 98 Автор(ы) : Shchepin V. V., Kodess M. I., Sazhneva Yu.Kh., Russkikh N.Yu. Заглавие : Synthesis, Structure, and Keto-Enol Tautomerism of 3-R1-5,5-R2,R2-6-R3-2,3,5,6-Tetrahydropyran-2,4-diones [Electronic resource] Место публикации : Russian Journal of General Chemistry. - 2005. - Vol. 75, № 10. - С. 1622-1627 Систем. требования: http://www.springerlink.com/content/p076p5q756p13052/fulltext.pdf Примечания : 17.10.2011 ББК : 54 Предметные рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: Ethyl esters of 2,4-dibromo-2-R1-4-R2-3-oxopentanoic and -hexanoic acids react with zinc and aliphatic or aromatic aldehydes under the conditions of the Reformatskii reaction to give 3-R1-5,5-R2, R2-6-R3-2,3,5,6-tetrahydropyran-2,4-diones, which are obtained in three forms: keto, enol with enolization of the keto group, and enol with enolization of the ester group. The keto form is isolated by crystallization from a mixture of CCl4 and petroleum ether; the first enol form, from MeOH, EtOH, and polar aprotic solvents; and the second enol form, from CHCl3. The second enol form is oxidized in DMSO to form a keto compound containing a hydroxy group at the 3-position of the heteroring Держатели документа: Центральная научная библиотека УрО РАН Доп.точки доступа: Shchepin, V. V.; Kodess, M. I.; Кодесс Михаил Исаакович; Sazhneva, Yu.Kh.; Russkikh, N.Yu.