105077-11-0Relevant academic research and scientific papers
An experimental estimation of aromaticity relative to that of benzene. The synthesis and NMR properties of a series of highly annelated dimethyldihydropyrenes: Bridged benzannulenes
Mitchell, Reginald H.,Iyer, Vivekanantan S.,Khalifa, Nasr,Mahadevan, Ramanathan,Venugopalan, Santhanagopalan,Weerawarna, Sirimevan Ananda,Zhou, Pengzu
, p. 1514 - 1532 (2007/10/02)
The synthesis of 13 trans-dimethyldihydropyrenes (bridged [14]annulenes) fused to one or more benzene, naphthalene, phenanthrene, phenalene, or quinoxaline rings and 6 cis-dihydropyrene derivatives from benzenoid precursors using either a thiacyclophane route or an electrocyclic addition of a furan to an annulyne followed by deoxygenation is reported. Their 1H NMR spectra are studied in detail to obtain correlations between 3JH,H coupling constants and the internal methyl proton chemical shifts and also between the latter and the more distant external annulene ring proton shifts. These linear correlations are then used to obtain a relationship between the relative aromaticity of benzene and the fused ring in question, such that the aromaticity of the fused ring can be estimated relative to that of a benzene ring simply from a measurement of chemical shift in the fused annulene.
A NEW SYNTHESIS OF BRIDGE DIFUNCTIONALISED METACYCLOPHANES USING A LOW VALENT TITANIUM COUPLING PROCEEDURE. THE FIRST SYNTHESIS OF -META-ORTHO-META-ORTHOCYCLOPHANES AND THEIR POSSIBLE CONVERSION INTO BIRADICALOID DIHYDROPYRENES.
Mitchell, Reginald H.,Weerawarna, Ananda S.
, p. 453 - 456 (2007/10/02)
Titanium (0) coupling of the terphenyl dialdehydes 11a,b gave 75-85percent yields of the bridge difunctionalised metacyclophanes 12a,b.Oxidation of these 1,2-diols to the 1,2-diketones was achieved with oxalyl chloride-DMSO followed by iPr2EtN at -30 deg C, which then on condensation with o-phenylene diamine provided a route to the first zero bridged meta-ortho-meta orthocyclophanes 15a,b.Irradiation of the latter gave purple compounds which we believe are the biradicaloid dihydropyrenes 16a,b.
