Microwave-Assisted Syntheses of <i>N</i>-Heterocycles Using Alkenone-, Alkynone- and Aryl-carbonyl <i>O</i>-Phenyl Oximes: Formal Synthesis of Neocryptolepine
作者:Fernando Portela-Cubillo、Jackie S. Scott、John C. Walton
DOI:10.1021/jo800847h
日期:2008.7.1
approach enabled the natural product trisphaeridine to be made. Starting from 2-phenylnicotinaldehyde derivatives, ring closures of the derived iminyl radicals onto the phenyl rings yielded benzo[h][1,6]naphthyridines. Similarly, ring closure onto a phenyl ring from a benzothiophene-based iminyl yielded a benzo[b]thieno[2,3-c]quinoline. By way of contrast, iminyl radical ring closure onto pyridine rings was
这项研究旨在提供一种新的“清洁”的合成方法,该方法将能够有效地制备已知和新颖的N-杂环。发现O-苯基肟是具有各种受体侧链的亚氨基自由基的优异前体。由含有戊-4-烯受体的O-苯基肟以高收率制得双羟基吡咯。使用六-5-烯基受体的类似过程未产生二氢吡啶,可能是因为6- exo - trig亚胺基的闭环太慢,无法与H原子抽象竞争。来自具有戊-4-炔型侧链的前体的亚胺基进行闭环,然后重排以提供吡咯衍生物。合适地取代的亚氨基自由基容易地闭环在芳族受体上,因此使得能够使用多个多环系统。喹啉由3-苯基丙烷经O-苯基肟制得。由2-甲酰基联苯开始的菲啶的合成特别有效,这种方法可以制备天然产物三菲啶。从2-苯基烟碱醛衍生物开始,衍生的亚氨基自由基在苯环上的闭环产生苯并[ h]] [1,6]萘啶。类似地,将苯并噻吩基亚胺基的苯环闭环,得到苯并[ b ]噻吩并[2,3- c ]喹啉。相比之下,未观察到亚吡啶基自由基
Thermal Rearrangement of Indolyl Oxime Esters to Pyridoindoles
作者:Fernando Portela-Cubillo、Brian A. Surgenor、R. Alan Aitken、John C. Walton
DOI:10.1021/jo801751a
日期:2008.10.17
Acyl oximes derived from a variety of indolylalkanones underwent a ring closure sequence during FVP to afford 9H-pyrido[2,3-b]indoles. Unlike UV light promoted reactions of oxime esters, the mechanism is almost certainly not mediated by iminyl radicals but probably involves tautomerism, elimination of acetic acid, and a final electrocyclic ring closure.
An alternative approach to the synthesis of functionalized pyrido[2,3-b]indoles
作者:Egle M Beccalli、Francesca Clerici、Alessandro Marchesini
DOI:10.1016/s0040-4020(01)00404-5
日期:2001.5
A new synthesis of α-carbolines was developed starting from the easily accessible 3-substituted indol-2(3H)-one derivatives 2 and enamines 3. The intermediates 4 afforded the α-carbolines 5 and 6 by thermal cyclization with ammonium acetate in glacial acetic acid by way of pyridine ring formation.
Baylis–Hillman acetates in organic synthesis: convenient one-pot synthesis of α-carboline framework – a concise synthesis of neocryptolepine
作者:Deevi Basavaiah、Daggula Mallikarjuna Reddy
DOI:10.1039/c2ob26339d
日期:——
A convenient, facile, and one-pot methodology for the synthesis of α-carbolines from Baylis–Hillman (BH) acetates, involving three steps (reactions), (1) mono alkylation of 2-nitroarylacetonitriles with BH-acetates, (2) reduction of nitro group into amino group using Fe/AcOH and (3) formation of two (five and six membered) rings, is presented. This methodology is successfully applied to the synthesis