Fluorene, oximes

Die Reaktion lauft wahrscheinlich iiber das Oxim so wird z. B. aus Kalium-9-ari-nitro-fluoren in 39%iger Ausbeute Fluorenon-oxim1 erhalten. 

Fluorene is oxidized to fluorenone in 65-70% yield by refluxing for 3 h with sodium dichromate in acetic acid [622], and 2-methylfluorene is converted into 2-methylfluorenone via its oxime on treatment with amyl nitrite (pentyl nitrite) [452]. The methylene group between two aromatic rings is oxidized in preference to the methyl group because nitrites react only with highly activated methylene groups (equation 177). 

A set of fluorophores derived from naphthalene, phenanthrene, pyrene, phenazine and fluorene have been conjugated to the 5 -ends of DNA and RNA to compare their physico-chemical properties. Decreasing the Ji-electron density led to an enhancement in thermal stability, attributable to more favourable Jt-Ji interactions. Stability is further enhanced by using nitrated fluorophores. Fluorescent labelling of ODNs using oxyamino modified fluorescein has been reported by the incorporation into DNA of aldehyde functions. The aldehyde function was attached either at the 5 -end via a phosphate linker or internally via 8-mercaptobutanal. Reduction of the resulting oxime was not necessary. 

Fluorenone oximes from fluorenes s. 16, 229 Phosphoric acid HgPO ... 

Amyl nitrite-potassium/alcohol Fluorenone oximes from fluorenes... 

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