Converting 9-methyldipyrrinones to 9-H and 9-CHO dipyrrinones

TETRAHEDRON

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Article

Boiadjiev, Stefan E.¹  Lightner, David A.¹ 

[1] Univ Nevada, Dept Chem, Reno, NV 89557 USA

关键词: pyrroles;    biliverdinoids;    Retro-Knovenagel reaction;    carbon acids;   

DOI  :  10.1016/j.tet.2007.06.009

来源: Elsevier

【 摘 要 】

Yellow 9-methyldipyrrinones can be converted readily and in high yields to symmetric linear tetrapyrroles, blue biliverdinoids, which are cleaved in half, smoothly at room temperature to afford yellow 9-H dipyrrinones, and 9-CHO dipyrrinones as their violet to orange colored adducts with the carbon acid used for the scission: thiobarbituric acid (TBA), N, N'-diethylthiobarbituric acid, barbituric acid, N, N'-dimethylbarbituric acid, and Meldrum's acid. The adducts, usually only of passing interest, are formally Knovenagel condensation products of a 9-CHO dipyrrinone with TBA and other carbon acids of this work, and a reverse Knovenagel reaction of such adducts leads to 9-CHO dipyrrinones. Under a set of improved reaction conditions the sequence thus efficiently converts 9-CH3 dipyrrinones to 9-H and 9-CHO dipyrrinones. (C) 2007 Elsevier Ltd. All rights reserved.

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