确定了 10 个 6 H -嘧啶并 [2,1- a ] 异吲哚的药理理化性质。发现所研究的化合物是弱碱基,其 ap K a范围为 2.38 至 3.46。此外,检查了所研究化合物与环糊精的缔合常数。以 1:1 的化学计量观察复合物的形成,发现 γ-环糊精是最好的复合物。最后,6 H -pyrimido[2,1- a ]-isoindoles 在 0.1 mol dm −3中的电化学氧化研究了乙腈中的高氯酸钠作为其可能代谢降解的模型。它被发现是一个单电子过程,半波电位的值在 1.34–1.62 V 的范围内(相对于 Ag/AgNO 3 /NaClO 4)。三种选定化合物的电氧化产物通过制备电解制备,随后通过质谱法鉴定。从获得的数据可以明显看出,6 H -嘧啶并[2,1- a ]异吲哚的电化学氧化开始于N -氧化物的形成,随后是分子的二聚化,或者与此相反,通过氧化裂解的嘧啶环。从代谢的角度来看,N-氧化是该途径的对应过程。
a tin-free radical cascade cyclizationprocess. Not only do amide-iminyl radicals lead to new tetracyclic heterocycles but these nitrogen-centered radical species also react in aromatic homolytic substitutions. Indeed, the amide-iminyl radical moiety unprecedentedly displaces methyl, methoxy, and fluorine radicalsfrom an aromatic carbon atom. This seminal reaction in the field of radical chemistry
Radical reactions with 3H-quinazolin-4-ones: synthesis of deoxyvasicinone, mackinazolinone, luotonin A, rutaecarpine and tryptanthrin
作者:W. Russell Bowman、Mark R. J. Elsegood、Tobias Stein、George W. Weaver
DOI:10.1039/b614075k
日期:——
Alkyl, aryl, heteroaryl and acyl radicals have been cyclised onto the 2-position of 3H-quinazolin-4-one. The side chains containing the radical precursors were attached to the nitrogen atom in the 3-position. The cyclisations take place by aromatic homolytic substitution hence retain the aromaticity of the 3H-quinazolin-4-one ring. The highest yields were obtained using hexamethylditin to facilitate cyclisation rather than reduction without cyclisation. The alkaloids deoxyvasicinone 2, mackinazolinone 3, tryptanthrin 4, luotonin A 5 and rutaecarpine 8 were synthesised by radical cyclisation onto 3H-quinazolin-4-one.
烷基、芳基、杂芳基和酰基自由基已环化连接到3H-喹唑啉-4-酮的2-位。含有自由基前体的侧链被连接到3-位的氮原子上。环化反应通过芳香均裂取代进行,因此保留了3H-喹唑啉-4-酮环的芳香性。使用六甲基二锡促进环化而不是直接还原而未发生环化,最高产率得以实现。生物碱去氧vasicinone 2、mackinazolinone 3、色胺酮4、luotonin A 5和rutaecarpine 8通过自由基环化反应合成于3H-喹唑啉-4-酮。
A General Copper-based Photoredox Catalyst for Organic Synthesis: Scope, Application in Natural Product Synthesis and Mechanistic Insights
available catalysts based on inexpensive, environmentally benign base metals are therefore strongly needed. Furthermore, expanding the toolbox of methods based on photoredox catalysis will facilitate the discovery of new light-mediated transformations. This article details the use of a simple copper complex which, upon activation with blue light, can initiate a broad range of radicalreactions.
A visible-light-induced/thiourea-mediated intramolecularcyclization of o-nitroarenes under mild conditions is realized for the first time, which provides an efficient and environmentally friendly way to access pharmaceutical relevant quinazolinone derivatives. The reaction can be easily extended to gram level by using a continuous-flow setup with high efficiency. Mechanistic investigation including
Reported herein is a visible-light-driven intramolecular C-N cross-coupling reaction under mild reaction conditions (metal- and photocatalyst-free, at room temperature) via a long-lived photoactive photoisomer complex. This strategy was used to rapidly prepare the N-substituted polycyclic quinazolinone derivatives with a broad substrate scope (>50 examples) and further exploited to synthesize the natural