title: Mechanism for phenanthridines synthesis by nitrogenation of 2-acetylbiphenyls in acidic solution: a DFT study.
abstract: The mechanism of phenanthridines synthesis from the nitrogenation of 2-acetylbiphenyls (1) by TMSN3in TFA has been studied by DFT calculations. Results at the B3LYP/6-311G(d) level showed that: 1) reaction of TMSN3/HN3with the protonated form of 1 (1H+), which generates the key intermediate Cx+by removal of TMSOH/H2O, is the rate determining step, and TMSN3as the nitrogen source is certainly preferred over HN3. 2) from Cx+, the two pathways leading to 2xH+and 3xH+are both thermodynamically and kinetically feasible and competitive to each other. 3) The high barriers of the reverse reactions suggest that the ratio of the final products 2x:3xis determined by the branching ratio of reaction rates of Cx+to intermediates Dx+in pass_I and Ex+in pass_II. Graphical Abstract DFT results indicate that the replacement of -OH by -N3which generates Cx+controls the consumption rate of 1xH+, and the ratio of Cx+transforms to Dx+and Cx+transforms to Ex+(k:k') determines the final ratio of products 2x:3x.
authors: School of Chemistry and Materials Science, Shanxi Normal University, Linfen, 041004, China.
authors: Lihui
authors: L
authors: Guo
authors: School of Chemistry and Materials Science, Shanxi Normal University, Linfen, 041004, China.
authors: Fuqiang
authors: F
authors: Zhang
authors: School of Chemistry and Materials Science, Shanxi Normal University, Linfen, 041004, China. xiangzh2000@hotmail.com.
authors: Xiang
authors: X
authors: Zhang
keywords: DFT calculations; Phenanthridines; TMSN3