7451-80-1Relevant academic research and scientific papers
The Bacterial Pigment from Pseudomonas lemonnieri. Part 2. The Synthesis of 3-n-Octanamidopyridine-2,5,6-trione; the Structure and Synthesis of Lemonnierin
Jain, Komal C.,Whalley, W. Basil
, p. 1788 - 1794 (2007/10/02)
Oxidation of 3-n-octanamido-5-aminocitrazinic acid (8; R=NH2) with iron(III) chloride gave a mixture of 3-n-octanamidopyridine-2,5,6-trione (1; R=H) and lemonnierin (22; R1=R2=H) identical with the blue pigment from our strain of Ps. lemonnieri.Various derivatives of 3-n-octanamidocitrazinic acid and of (1; R=H) are described.Condensation of (1; R=H) with citrazinic acid (8; R=NH2) gave 3-(6-hydroxy-5-octanamido-2-oxo-1,2-dihydro-3-pyridylimino)-6-hydroxy-5-octanamido-2-pyridone (14) (cf.Knackmuss3,4) which differs from lemonnierin but may be converted into lemonnierin, with which it is isomeric, by copper(II) acetate-pyridine.Lemonnierin thus appears, at least in part, to be a di-free radical, of type (22; R1=R2=H), with g=2.004.Experiments with deuteriated intermediates together with the synthesis of the corresponding acetyl analogue (17) of the imine (14) and the acetyl analogue (25) of lemonnierin, substantiate the structure (22; R1=R2=H) for our pigment.Imines of type (14) are converted into the corresponding 3,3'-bipyridylidenequinone (21) by hot acetic acid, thus providing a new and improved route to these quinones.
