Neue reaktionen der carcinogenen kohlenwasserstoffe 3,4-benzypyren, 9,10-dimethyl-1,2-benzanthracen und 20-methylcholanthren

Polypyrene Dendrimers

“…The large steric hindrance between pyrenes at the 1-position results in a high degree of twisting, as shown by the computed structures (AM1, Figure 3). The calculated dihedral angle between the core and the first branch is 65-668 for Py(5) and 71-738 for Py (17), with the angle between the first and the second branch in Py(17) around 84-898. These new fully aromatic dendrimers are relevant for artificial light-harvesting in a spatially welldefined three-dimensional architecture, comprising only one type of chromophore.…”

“…From Py(2) to Py(17), the broad absorption band red shifted from the structured part of the spectrum increases in relative intensity. This broad band reflects the intramolecular interaction between the pyrene moieties in the Py(n) compounds, which becomes stronger from Py(2) to Py (17). The extinction coefficient per pyrene subunit at the maximum of the absorption spectrum e max /n ( for Py (17).…”

“…Subsequently, bromide 2 was converted into the pinacol boronic ester 3 under Suzuki-Miyaura conditions [16] in 98 % yield. The optimized coupling reaction of compound 3 (6.0 equivalents) with 1,3,6,8-tetrabromopyrene gave a complex mixture of products from which 1,3,6,8tetrakis(7-tert-butylpyren-1-yl)pyrene Py (17) was successfully isolated in 38 % yield using preparative HPLC (Scheme 1).…”

Aktivierung von Steroidsystemen zu alkylierenden Agenzien / Activation of Steroid Systems to Alkylating Agents

“…Es ist bekannt, daß unter den Bedingungen der Iodreaktion bei aromatischen Kohlenwasserstoffen [8] Die Produkte sind sehr instabil, sie zersetzen sich oberhalb 100 °C, Rf-Werte in "4 K" als Entwickler: um 0,0-0,2. Die Ausbeuten hegen bei 10%.…”

Periodic acid, a novel oxidant of polycyclic, aromatic hydrocarbons

“…Thus, oxidati ve dimerization of I to 2 probably proceeds through intermediate Ia as depicted. Ab strac tion of a 1T-elec tron by a molecule of periodic acid fro m an aromatic nucle us would produce the pyrene radical la ; dimerization to the stable l,l'-bipyrene (2) would follow the loss of one proton [60][61][62]. The overall oxid ation process of I to dimer 2 involves the loss of two protons.…”