Issue 22, 1996

Investigation of a ‘reverse’ approach to extended porphyrin systems. Synthesis of a 2,3-diaminoporphyrin and its reactions with α-diones

Abstract

A 2,3-diaminoporphyrin has been synthesised for the first time and its reaction with α-diones has been examined. Two regioselective routes to the precursor 2-amino-3-nitroporphyrins have been established. 2-Aminoporphyrins are directly nitrated on the porphyrin ring in the 3-position while 2-nitroporphyrins react with acylamide ions regioselectively at the 3-position and can be converted to the required 2-amino-3-nitroporphyrins by hydrolysis of the amide bond. 2,3-Diamino-5,10,15,20-tetraarylporphyrins are prepared by transfer hydrogenation of the corresponding 2-amino-3-nitroporphyrins but are relatively unstable. Electrochemical measurements show that 2,3-diaminoporphyrins are easily oxidised and this probably accounts for their instability. Condensation of the 2,3-diaminoporphyrin 29 with the α-diones benzil and cyclohexane-1,2-dione occurs readily and in good yield to give the ring annulated systems 31 and 32, respectively. Reaction with o-benzoquinone, however, causes decomposition of the diaminoporphyrin 29 making ‘reverse’ synthesis of quinoxalinoporphyrins and related polyporphyrin systems much less attractive than the alternate approach involving condensation of a porphyrin-2,3-dione with o-phenylenediamine and related diamines.

Article information

Article type
Paper

J. Chem. Soc., Perkin Trans. 1, 1996, 2675-2684

Investigation of a ‘reverse’ approach to extended porphyrin systems. Synthesis of a 2,3-diaminoporphyrin and its reactions with α-diones

M. J. Crossley, L. G. King, I. A. Newsom and C. S. Sheehan, J. Chem. Soc., Perkin Trans. 1, 1996, 2675 DOI: 10.1039/P19960002675

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Spotlight

Advertisements