Conjugated heptaene

SCHEME 17 Literature example for the successful ozonolysis of a conjugated heptaene. 

Polyene antibiotics, such as amphotericin B (II) which contains seven conjugated double bonds (heptaene moiety), are subject to attack by peroxyl radicals, leading to aggregation and loss of activity. ... 

The major differences between the optical spectroscopy of model polyenes and short apo-carotenes and the longer, more conjugated carotenoids employed in photobiology are illustrated in Fig. 5. Most striking is the aoss-over from the S,(2 Ag) So(l A ) emission observed for the apo-heptaene (7c) to die dominant, S,( 1 B ) - So( 1 Ag) fluorescence of the analogous apo-nonaene (9). Similar changes... 

The VIS spectrum of the yellow alkali treated product of the blue oxonium salt also contained products with octaene-, heptaene- and hexaene like chromophores [80], compatible with conjugate addition and charge delocalisation in the blue oxonium ion. 

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