153763-95-2Relevant academic research and scientific papers
Nuclear versus Side-Chain Bromination of Methyl-Substituted Anisoles by N-Bromosuccinimide
Gruter, Gert-Jan M.,Akkerman, Otto S.,Bickelhaupt, Friedrich
, p. 4473 - 4481 (1994)
The reactions of methyl-substituted anisoles with N-bromosuccinimide in CCl4 are reported.In the absence of a catalyst and under irradiation, some of these substrates undergo nuclear bromination in competition with the well-known side-chain bromination.With 2-methylanisole and with 2,6-dimethylanisole, nuclear bromination is not observed, whereas with 3,5-dimethylanisole, nuclear bromination at the 4-position is the dominating reaction.Investigation of the reactivity of several other methyl-substituted anisoles revealed the following general trend: methyl-substituted anisoles are attacked at the position para to the methoxy group rather than at the side chain when (at least) two methyl groups are present at positions 3 and 5.When positions 2 and 6 are both occupied, nuclear bromination is retarded; in 2,6-dimethylanisole and 2,3,6-trimethylanisole, only side-chain bromination is observed.In contrast, in 2,3,5,6-tetramethylanisole, the 4-position is sufficiently reactive to be brominated, because the decrease in reactivity by the presence of two methyl groups at positions 2 and 6 is overruled by the two additional methyl groups at positions 3 and 5; as a result, both nuclear and side-chain bromination occur.The observed chemospecificity can be rationalized by a difference in mechanism: the side-chain bromination is radical reaction, while the nuclear bromination is an electrophilic aromatic substitution reaction, which is so far contrary to expectation, as irradiation had been expected to favor radical processes.
Substituents Have a Large Effect on Photochemical Generation of Benzyl Cations and DNA Cross-Linking
Fan, Heli,Sun, Huabing,Peng, Xiaohua
, p. 7671 - 7682 (2018/05/14)
Photoactivated DNA interstrand cross-linking agents have a wide range of biological applications. Recently, several aryl boronates have been reported to induce DNA interstrand cross-link (ICL) formation via carbocations upon photoirradiation. Herein, we synthesized a series of new bifunctional phenyl compounds to test the generality of such a mechanism, and to understand how the chemical structure influences carbocation formation and the DNA cross-linking process. These compounds efficiently form DNA ICLs via generated benzyl cations upon 350 nm irradiation. The DNA cross-linking efficiency and the pathway for carbocation generation depend on both the aromatic substituents and the leaving groups. Bromine as a leaving group facilitates the DNA cross-linking process in comparison with trimethyl ammonium salt. Both electron-donating and -withdrawing substituents induce bathochromic shifts, which favor photoinduced DNA ICL formation. For the bromides, the benzyl cation intermediates were generated through oxidation of the corresponding benzyl radicals. However, for the ammonia salts, the benzyl cations were formed through two pathways: either through oxidation of the benzyl radicals or by direct heterolysis of the C?N bond. Photoinduced C?N homolysis to form benzyl radicals occurred with compounds having donating substituents, whereas direct heterolysis of the C?N bond occurred with those bearing withdrawing substituents. The adducts formed between 1 a and four natural nucleosides were characterized, indicating that the alkylation sites for the photogenerated benzyl cations are dG, dA, and dC.
Hydrogen peroxide activated quinone methide precursors with enhanced DNA cross-linking capability and cytotoxicity towards cancer cells
Wang, Yibin,Fan, Heli,Balakrishnan, Kumudha,Lin, Zechao,Cao, Sheng,Chen, Wenbing,Fan, Yukai,Guthrie, Quibria A.,Sun, Huabing,Teske, Kelly A.,Gandhi, Varsha,Arnold, Leggy A.,Peng, Xiaohua
, p. 197 - 207 (2017/04/07)
Quinone methide (QM) formation induced by endogenously generated H2O2 is attractive for biological and biomedical applications. To overcome current limitations due to low biological activity of H2O2-activated QM
BILATERALLY-SUBSTITUTED TRICYCLIC COMPOUNDS FOR THE TREATMENT OF HUMAN IMMUNODEFICIENCY VIRUS TYPE-1 (HIV-1) INFECTION AND OTHER DISEASES
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, (2014/09/03)
The invention relates to bilaterally-substituted tricyclic compounds and pharmaceutical compositions containing them, for use as medicaments. Due to their ability to interact with an internal RNA loop and to mimic a protein a-helix these compounds are effective in the treatment and/or prevention of HIV-1 (Human Immunodeficiency Virus-1) infection and other diseases such as those caused by other RNA viruses and by gram-positive and gram-negative bacteria, or infectious or chronic diseases responsive to inhibition of DNA transcription, or infectious or chronic diseases where these compounds can be used to modulate the function of RNA internal loops, or infectious or chronic diseases where these compounds can be used as agonists or inhibitors of a-helical proteins in interaction with other biomolecules.
Structure-based design of an RNA-binding p-terphenylene scaffold that inhibits HIV-1 rev protein function
Gonzalez-Bulnes, Luis,Ibanez, Ignacio,Bedoya, Luis M.,Beltran, Manuela,Catalan, Silvia,Alcami, Jose,Fustero, Santos,Gallego, Jose
, p. 13405 - 13409 (2014/01/06)
Rev(ersing) RNA binding: RNA-binding inhibitors based on a bilaterally substituted p-terphenylene scaffold (green) project their substituents in a broad spatial angle and reproduce the interactions of a protein α-helix (red) embedded in its RNA receptor.
