Sharada Duddu S, Muresan Ana Z, Muthukumaran Kannan, Lindsey Jonathan S
Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA.
J Org Chem. 2005 Apr 29;70(9):3500-10. doi: 10.1021/jo050120v.
[reaction: see text] Palladium porphyrins are valuable photosensitizers and luminescent agents in biology and materials chemistry. New methodology is described wherein a 1-acyldipyrromethane is converted into the palladium chelate of a trans-A(2)B(2) porphyrin via a one-flask reaction. The reaction entails self-condensation of the 1-acyldipyrromethane in refluxing ethanol containing KOH (5-10 mol equiv) and Pd(CH(3)CN)(2)Cl(2) (0.6 mol equiv) exposed to air. This direct route to palladium porphyrins is more expedient than the four steps of the traditional synthesis: (1) reduction of the 1-acyldipyrromethane; (2) acid-catalyzed condensation; (3) oxidation of the porphyrinogen intermediate; and (4) metal insertion. The new synthesis requires neither acid nor DDQ and formally entails only a 2e(-) + 2H(+) oxidation overall versus the traditional multistep synthesis which requires a 2e(-) + 2H(+) reduction per each 1-acyldipyrromethane (4e(-) + 4H(+) overall) followed by a 6e(-) + 6H(+) oxidation. The analogous reaction of a 1,9-diacyldipyrromethane and a dipyrromethane also gives the palladium porphyrin. Seven palladium porphyrins have been prepared in yields of 25-57%. The direct route also can be used with Cu(OAc)(2).H(2)O to give the copper porphyrin albeit in low yield. In summary, this methodology readily affords palladium porphyrins directly from acyldipyrromethanes.
[反应：见正文] 钯卟啉在生物学和材料化学中是有价值的光敏剂和发光剂。本文描述了一种新方法，通过单瓶反应将1-酰基二吡咯甲烷转化为反式A(2)B(2)卟啉的钯螯合物。该反应需要1-酰基二吡咯甲烷在含有KOH（5-10摩尔当量）和Pd(CH(3)CN)(2)Cl(2)（0.6摩尔当量）的回流乙醇中进行自缩合，并暴露于空气中。这条合成钯卟啉的直接路线比传统合成的四个步骤更为简便：(1) 1-酰基二吡咯甲烷的还原；(2) 酸催化缩合；(3) 卟啉原中间体的氧化；以及(4) 金属插入。新合成方法既不需要酸也不需要2,3-二氯-5,6-二氰基-1,4-苯醌（DDQ），与传统的多步合成相比，整个过程仅涉及形式上的2e(-) + 2H(+)氧化，而传统多步合成每个1-酰基二吡咯甲烷需要2e(-) + 2H(+)还原（总共4e(-) + 4H(+)），随后是6e(-) + 6H(+)氧化。1,9-二酰基二吡咯甲烷和二吡咯甲烷的类似反应也能得到钯卟啉。已制备出七种钯卟啉，产率为25-57%。该直接路线也可与Cu(OAc)(2).H(2)O一起使用以得到铜卟啉，尽管产率较低。总之，该方法能直接从酰基二吡咯甲烷轻松制得钯卟啉。
