Phototransformation of 3-alkoxychromenones: regioselective photocyclisation and dealkoxylation
作者:Radhika Khanna、Aarti Dalal、Ramesh Kumar、Ramesh C. Kamboj
DOI:10.1039/c5pp00318k
日期:2015.12
observed through ring closure at the 2'-position. This behaviour has been found to be in accordance with the directive influence observed in free radical aromatic substitutions. This regioselective photocyclisation is further supported by calculations made from 3D structures (MM2 program). In addition, during the irradiation of these substrates, 2-(3-methoxyphenyl)-4H-chromen-4-ones were also realised through
已经描述了一些在3-位带有丙炔氧基部分的2-(3-甲氧基苯基)-4H-铬-4-酮的光转化。在使用汞灯(125 W)的吡咯烷酮过滤的紫外光进行光解时,这些色酮生成大量的5-乙炔基-2-甲氧基-6-氧杂-苯并[5,6-c]黄嘌呤-7-外来的四环支架。已经设想这些光产物通过γ-H抽象机理通过在最初形成的1,4-双基的2-(3'-甲氧基)苯基部分的6'-位置上的区域选择性闭环而产生。通过在2'-位的闭环,未观察到任何产物。已经发现这种行为与在自由基芳族取代中观察到的指导影响一致。由3D结构(MM2程序)进行的计算进一步支持了这种区域选择性的光环化反应。另外,在这些底物的辐照过程中,还通过脱烷氧基化实现了2-(3-甲氧基苯基)-4H-铬烯-4-酮。底物和光产物的结构已通过其光谱学(IR,NMR,质谱)研究确定。