o-Hydroxylmethylphenylchalcogens: Synthesis, Intramolecular Nonbonded Chalcogen···OH Interactions, and Glutathione Peroxidase-like Activity

Abstract

[Structure: see text]. The synthesis and characterization of a series of organochalcogen (Se, Te) compounds derived from benzyl alcohol 13 are described. The synthesis of the key precursor dichalcogenides 15, 22, and 29 was achieved by the ortho-lithiation route. Selenide 18 was obtained by the reaction of the dilithiated derivative 14 with Se(dtc)2. Oxidation of 15 and 22 with H2O2 afforded the corresponding cyclic ester derivatives 17 and 24, respectively. Oxidation of selenide 18 with H2O2 affords the spirocyclic compound 19. The presence of intramolecular interactions in dichalcogenides 15 and 22 has been proven by single-crystal X-ray studies. The cyclic compounds 17 and 19 have also been characterized by single-crystal X-ray studies. GP(X)-like antioxidant activity of selenium compounds has been evaluated by the coupled bioassay method. Density functional theory calculations at the mPW1PW91 level on ditelluride 22 have identified a fairly strong nonbonding interaction between the hydroxy oxygen and tellurium atom. The second-order perturbation energy obtained through NBO analysis conveys the involvement of n(O) --> sigma(Te-Te) orbital overlap in nonbonding interaction. Post wave function analysis with the Atoms in Molecules (AIM) method identified distinct bond critical point in 15 and 22 and also indicated that the nonbonding interaction is predominantly covalent. Comparison between diselenide 15 and ditelluride 22 using the extent of orbital interaction as well as the value of electron density at the bond critical points unequivocally established that a ditelluride could be a better acceptor in nonbonding interaction, when the hydroxy group acts as the donor.

Catalytic application of selenium and tellurium compounds as glutathione peroxidase enzyme mimetics

“…15 The same author also studied the behavior of diselenide 13 with intramolecular Se•••O nonbonding interactions and cyclic seleninate ester 14, which is conveniently produced by oxidation of 13 with H 2 O 2 . 16 Both substances exhibited better GPx like activity than ebselen.…”

Substituent Effects on the Stability and Antioxidant Activity of Spirodiazaselenuranes

“…The significant PN scavenging activity of all the spirodiazaselenuranes 29-35 than that of compound 12 also proves that selenium centre undergoes further oxidation in the presence of excess PN producing the corresponding selenurane oxides. Interestingly, the heterocyclic pyridine substituted selenides (16)(17)(18) and spirodiazaselenuranes (30)(31)(32) were found to be excellent GPx mimics and also effective inhibitors for the PN-mediated nitration and oxidation reactions. This strongly indicates that the stability of the Se-N bonds in the spiro compounds and the antioxidant activity of diaryl selenides and spirodiazaselenuranes are greatly influenced by the heterocylic substituents present at the nitrogen atoms.…”

“…The solvent was removed under vacuum to obtain a light yellow solid, which was then purified by flash chromatography using petroleum ether/ethyl acetate as the eluents. N-(4-methoxybenzyl) (16); White solid with 88% yield. (17): Yellowish solid with 87% yield.…”

“…In 2004, Back and co-workers showed for the first time that spirodioxyselenurane 4 and its tellurium analogue 5 exhibit very good antioxidant activity by mimicking the glutathione peroxidase (GPx) enzyme [12], which protects the organism from oxidative damage by catalyzing the reduction of peroxides using thiol as the cofactor [13,14]. However, the corresponding aromatic derivatives 6-7 were found to be much less active than the aliphatic compounds 4-5 [15,16]. Several sulfurane oxides and selenurane oxides such as 8-10, in which the chalcogen atoms are in the higher oxidation state, were also synthesized and isolated ( Figure 1) [17][18][19].…”

Atoms‐in‐Molecules Analysis of Extended Hypervalent Five‐Center, Six‐Electron (5c–6e) C2Z2O Interactions at the 1,8,9‐Positions of Anthraquinone and 9‐Methoxyanthracene Systems

“…[10] The method can be applied to weak bonds as well as classical chemical bonds. [11][12][13][14][15][16] Some criteria have been proposed to enable weak interactions to be recognized, separate from the classical bonds, based on the nature of the bond critical points (BCPs). [10] We applied the AIM method to the extended hypervalent 5c-6e C 2 Z 2 O (Z= Se, S, and O) unit in the anthraquinone (ATQ) system, 1,8-bis(methylchalcogeno)anthraquinones (1, 2 ATQ: 1 (Z = Se), 2 (Z = S), and 3 (Z = O)) after determination of the structures by means of X-ray crystallographic analysis.…”