Synthesis, chemical properties and mutagenicity of 1,6- and 3,6-dinitrobenzo(a)pyrenes.

The role of electronic properties to the mutagenic activity of 1,6- and 3,6-dinitrobenzo[a]pyrene isomers

“…Additionally, ı s NO 2 value in position 6 (0.14) is somewhat lower than that in 1 (0.22) and 3 (0.21) position. As a consequence, for the neutral species, nitro group in position 6 is less susceptible to reduction than that in positions 1 and 3, in agreement with previous experimental results [15]. Introduction of the two nitro groups increases EA value of the BaP moiety by ca.…”

“…This result is also confirmed by the ε LUMO data. Present EA and ε LUMO data are consistent with electrochemical reduction potentials involving the transfer of two electrons previously obtained through cyclic voltammetry measurements [15], being −0.65 and −0.67 V for 1,6-DNBaP and 3,6-DNBaP, respectively. Differently, we note that for NBaPs isomers, where mutagenic activity increases in the order 6-NBaP < 1-NBaP ∼ 3-NBaP, B3LYP/6-31+G* SCF EA value varies, being 1.34, 1.58, 1.55 eV, respectively [54].…”

“…In the case of dinitrobenzo[a]pyrenes (DNBaP), directmutagenic activities of two isomers, 1,6-DNBaP and 3,6-DNBaP, obtained through Salmonella typhymurium strains TA98 and YG1024 in the absence of metabolic activation system (S9) were investigated [15][16][17][18]. The results of both the tests concordantly show that 3,6-DNBaP exhibits substantially higher mutagenic potencies than those for 1,6-DNBaP isomer.…”

“…Additionally, according to tests on F344/DuCrj rats, 3,6-DNBaP is demonstrated to be more carcinogenic than 1,6-DNBaP isomer [19]. Due to the presence of two withdrawal nitro substituents, 3,6-DNBaP is predicted to be more mutagenic than nitrobenzo[a]pyrenes (NBaP) [15][16][17][18]20]. However, owing to their high sensitivity to UV radiations, detection in the environment of DNBaPs is a hard task [21].…”

“…Hitherto, experimental and theoretical structural data of DNBaPs are not available, while X-ray structure of 6-NBaP [22] and Density Functional Theory (DFT) [23] geometries of 1-, 3-and 6-NBaP isomers [24] have been recently obtained. It is well established that nearly planar 1-NBaP and 3-NBaP are more mutagenic than the quasi-orthogonal 6-NBaP isomer [15][16][17][18]20].…”