Synthesis of Phenanthridine Derivatives by Microwave-Mediated Cyclization of o-Furyl(allylamino)arenes
摘要:
A novel and efficient synthesis of phenanthridines and aza analogues is reported. The key step is a microwave-mediated intramolecular Diels-Alder cyclization of o-furyl(allylamino)arenes. In the presence of a catalytic amount of acid, the DA-adduct reacts further to give the dihydrophenanthridines, which easily can be oxidized to fully aromatic compounds by air in the presence of UV light or by DDQ.
long as the Diels–Alderadduct contains a hydrogen atom in the 6a-position. Aromatization of the phenanthridine C-ring does not occur when the cyclization is performed under conventional heating conditions. The IMDAF reaction can, under these conditions, lead to Diels–Alderadducts or to phenanthridines with partially saturated and functionalized C-rings, depending on the detailed structure of the starting
在微波和常规加热条件下,通过邻呋喃基(烯基氨基)芳烃的 IMDAF(呋喃分子内 Diels-Alder 反应)环化合成了在 C 环中官能化的菲啶。反应的结果高度依赖于亲二烯体和芳烃组分的取代模式。5,6-二氢菲啶很容易被氧化成全芳香族菲啶,只要 Diels-Alder 加合物的 6a 位含有氢原子,就可以在微波条件下形成。在常规加热条件下进行环化时,不会发生菲啶 C 环的芳构化。在这些条件下,IMDAF 反应会导致 Diels-Alder 加合物或具有部分饱和和功能化 C 环的菲啶,
Formation of 8-Hydroxyphenanthridines by Microwave-Mediated IMDAF Reactions; Synthesis Directed towards Lycorine Alkaloids
8‐Hydroxyphenathridines have been synthesized from N‐propargyl‐ortho‐furylanilines by a one‐pot intramolecular Diels–Alder reaction on furans (IMDAF) reaction and aromatization. N‐Propargyl‐7‐furylindol(in)es also underwent IMDAF cyclization to give (4,5‐dihydro)7H‐pyrrolo[3,2,1‐de]phenanthridin‐9‐ols These are structurally closely related to bioactive lycorine alkaloids.
通过一锅内呋喃分子内Diels-Alder反应(IMDAF)和芳构化反应,由N-炔丙基-邻-呋喃基苯胺合成了8-羟基苯并吡啶。N-炔丙基-7-呋喃啉(in)也经历了IMDAF环化反应,得到(4,5-二氢)7 H-吡咯并[3,2,1- de ]菲啶-9-醇这些在结构上与生物活性的赖氨酸密切相关生物碱。