报道了双环和三环稠合的1,2,4-恶二唑啉的有机催化合成。该反应通过使用2,4,6-三(4-氟苯基)四氟硼酸吡啶鎓(T(p -F )PPT)作为有机催化剂和分子氧作为绿色氧化剂,通过对相应的肟肟的氧化环化来进行。在转化过程中,T(p- F )PPT既是亲电子催化剂又是光催化剂,通过可见光照射可促进反应。本文介绍的方法为制备具有不同功能的1,2,4-恶二唑啉提供了一条直接途径,并且在经济上非常经济。
报道了双环和三环稠合的1,2,4-恶二唑啉的有机催化合成。该反应通过使用2,4,6-三(4-氟苯基)四氟硼酸吡啶鎓(T(p -F )PPT)作为有机催化剂和分子氧作为绿色氧化剂,通过对相应的肟肟的氧化环化来进行。在转化过程中,T(p- F )PPT既是亲电子催化剂又是光催化剂,通过可见光照射可促进反应。本文介绍的方法为制备具有不同功能的1,2,4-恶二唑啉提供了一条直接途径,并且在经济上非常经济。
Photoinduced Molecular Rearrangements. Some Investigations of the Photochemical Behavior of 3-(Acylamino)-1,2,5-Oxadiazoles (Furazans)
作者:Silvestre Buscemi、Nicolo Vivona、Tullio Caronna
DOI:10.1021/jo00118a028
日期:1995.6
Mechanistic investigations of the photochemical behavior of some 3-(acylamino)-1,2,5-oxadiazoles (furazans) are reported. Irradiations of 3-(aroylamino)-4-methyl- and 3-(acetylamino)-4-phenylfurazans at lambda = 254 nm in methanol, and in methanol containing pyrrolidine, are considered. Photochemical processes follow different routes depending on the actual chromophore in the photoreaction. In the irradiation of 3-(aroylamino)-4-methylfurazans, two photochemical pathways involving a different multiplicity of excited states are suggested: cleavage of the ring O(1)-N(5) bond via a singlet excited state (developing into nitrile oxides or carbodiimides, from which final products arise), or preliminary ring-closure involving the aroylamino group via a triplet excited state, respectively. In the irradiation of 3-(acetylamino)-4-phenylfurazan, photolytic intermediates arising from the cleavage of both the O(1)-N(2) and O(1)-N(5) bonds develop into the final products by reaction with the nucleophilic species present.