KF-Al2O3 induced the condensation of 2-nitrofluorene and para-substituted acetophenones with aromatic aldehydes
In the presence of KF-Al2O3 as a solid base, 2-nitrofluorene 1 condensed with aromatic aldehydes 2a-f in methanol to give 2-nitrodibenzofulvenes 3a-f in high yield. The para-substituted acetophenones 4a-f reacted with cinnamic aldehyde to give 1, 5-diaryl-2, 4-pentadien-1-ones 6a-f in moderate yield.
Yan,Sun
p. 3809 - 3814
(2007/10/03)
Synthesis and structural assignment of 2,4′-disubstituted benzylidenefluorenes and 4′-substituted benzylidene-1-azafluorenes
In the course of a study aimed at the investigation of edge-to-face arene-arene interactions, substituted benzylidenefluorenes 8-16 and benzylidene-1-azafluorenes 20-24 were synthesized as mixtures of E-Z-isomers. The full structural assignment of these compounds, performed by 2D NMR experiments, is described together with a study of their E-Z isomerization under equilibrating conditions. For compounds 8-16 no correlation was observed between the electron-donating or electron-withdrawing nature of the substituent groups and the E/Z equilibrium ratios. In the case of 20-24 the predominance of the E-isomers seems to depend exclusively on the N-lone pair-benzylidene ring electronic repulsion rather than on the nature of the para substituent on the aromatic ring.
Annunziata, Rita,Molteni, Valentina,Raimondi, Laura
p. 520 - 528
(2007/10/03)
Ultrasonicated condensation of indene and 2-nitrofluorene with aromatic aldehydes catalyzed by bis-(p-methoxyphenyl)telluroxide (BMPTO)
The condensation of indene or 2-nitrofluorene with aromatic aldehydes catalyzed by bis-(p-methoxyphenyl)telluroxide (BMPTO) under ultrasonic wave irradiation gave corresponding fulvenes in fair to good yield.