94006-35-6Relevant academic research and scientific papers
Site-Selective Thiolation of (Multi)halogenated Heteroarenes
Sandfort, Frederik,Knecht, Tobias,Pinkert, Tobias,Daniliuc, Constantin G.,Glorius, Frank
supporting information, p. 6913 - 6919 (2020/05/14)
A general and simple strategy for the site-selective thiolation of various pharmaceutically relevant electron-rich heteroarenes with thiols is reported. This mild and reliable photocatalytic protocol enables C-S coupling at the most electron-rich position of the (multi)halogenated substrates, complementing established methodologies. Experimental and computational studies suggest a radical chain mechanism with the key step being a homolytic aromatic substitution of the heteroaryl halide by an electrophilic thiyl radical, highlighting an underdeveloped reactivity mode.
Unique para-effect in electron ionization mass spectra of bis(perfluoroacyl) derivatives of bifunctional aminobenzenes
Tretyakov, Kirill V.,Todua, Nino G.,Borisov, Roman S.,Zaikin, Vladimir G.,Stein, Stephen E.,Mikaia, Anzor I.
body text, p. 2529 - 2532 (2011/12/02)
A new kind of 'para-effect' under electron ionization (EI) conditions has been discovered for a series of bis(perfluoroacyl) derivatives of o-, m- and p-phenylenediamines, -hydroxybenzeneamines and -mercaptobenzeneamines of a common structure RCOX-C6H4-NHCOR (X=NH, S, O; R=CF3, C2F5, C3F7). Only the para-isomers showed successive loss of a radical RCO? and a molecule RCN, leading to very intense peaks in the EI spectra. The composition and the origin of the [M-COR-NCR]+ ions were confirmed by exactmassmeasurements and linked scan experiments. The proposedmechanism of their formation takes into account likely para-quinoid structures of the precursor ions. A similar rearrangement has not been observed for para-isomers in the series of bis(perfluoroacyl) derivatives of benzenediols, mercaptophenols and dimercaptobenzenes.
Electronic properties of para-substituted thiophonols and disulfides from 13C NMR spectroscopy and ab initio calculations: Relations to the Hammett parameters and atomic charges
Sengar, Raghvendra S.,Nemykin, Victor N.,Basu, Partha
, p. 1115 - 1123 (2007/10/03)
A large number of para-substituted benzene thiols and the corresponding disulfides were synthesized and characterized by 1H NMR, 13C NMR, and IR spectroscopies. Geometrics of all sixteen thiols and fourteen disulfide compounds were optimized at the B3LYP/6-31G(d) level, while the electronic structure and the 13C isotropic shifts were calculated by ab initio Hartree-Fock method coupled with the Gauge-Independent Atomic Orbital (GIAO) algorithm and a 6-31+G(d,p) basis set. The calculated 13C NMR isotropic shifts exhibit admirable agreement (δ rmsd ~4.6 ppm) with the experimental data. The chemical shift of para-substituted carbon showed a linear correlation with Hammett constants (σp and σn+). Using this methodology the σp+ constants for the dendritic ligands have been estimated to be 0.25 and 0.24 for 2(n) and 2(o), respectively. In addition, the NBO charges on the sulfur atoms shows a latent response with the σp+ parameter. The atomic charge on the thiophenolato sulfur is invariant with the electron withdrawing ability of the substituents, however, the charge increases with increasing electron-withdrawing power.
