Reaction of cyclic imidates with α,β-unsaturated esters: Synthesis of new pyrrolo[2,1-b]-1,3-oxazine and pyrido[2,1-b]-1,3-oxazine derivatives
作者:Shogo Ihara、Takashi Soma、Daigo Yano、Shunichi Aikawa、Yasuhiko Yoshida
DOI:10.1002/jhet.539
日期:2011.5
or methyl 6‐oxo‐3,4‐dihydro‐2H,6H‐pyrido[2,1‐b]‐1,3‐oxazine‐7‐carboxylates 7a, 7b, 7c, 7d, 7e, 7f (32–59%), respectively. In these reactions, 1a, 1b, 1c, 1d, 1e, 1f (cyclic imidates, iminoethers) functioned as their N,C‐tautomers (enaminoethers) 2 to α,β‐unsaturated esters 2, 4, and 6 to give annulation products 3, 5, and 7 following to the elimination of methanol, respectively. J. Heterocyclic Chem
环酰亚胺,2-苄基-5,6-二氢-4 H -1,3-恶嗪1a,1b,1c,1d,1e,1f与乙炔基二羧酸二甲酯2,三乙烯三羧酸三甲酯4或二甲基-2-甲基的环加成反应(甲氧基亚甲基)丙二酸二乙酯6,得到新的稠合杂环化合物,例如甲基(6-氧代-3,4-二氢-2 ħ吡咯并[2,1- b ] -1,3-恶嗪-7-亚基)乙酸酯3a中,3b,3c,3d,3e,3f(71-79%),二甲基-2-(6-氧代-3,4,6,7-四氢-2- ħ吡咯并[2,1- b ] -1,3-恶嗪-7-基)丙二酸酯5B,5c,5d,5e,5f(43–71%)或甲基6-氧代-3,4-二氢-2 H,6 H-吡啶基[ 2,1- b ] -1,3-恶嗪-7-羧酸盐分别为7a,7b,7c,7d,7e,7f(32–59%)。在这些反应中1a,1b,1c,1d,1e,1f(环状亚氨酸酯类,iminoethers)充当其N,C -tauto