35510-06-6Relevant academic research and scientific papers
SYNTHESIS OF DIATROPIC HIGHLY BENZANNELATED ANNULENES.
Mitchell, Reginald H.,Mahadevan, Ramanathan
, p. 5131 - 5134 (1981)
The first examples of annelated cis-dihydropyrenes, 16, 18, 19, together with a number of highly annelated trans-dihydropyrenes, 2-4 and, 17, are described.All are diatropic and indicate that higher annelation does not remove the delocalisation in a macrocyclic ring.
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.
