Synthesis, characterization of N-, S-, O-substituted naphtho- and benzoquinones and a structural study

Abstract

The new series of N-, SO O-substituted 1,4-naphthoquinone and SO O-substituted 1,4benzoquinone compounds were synthesized via vinylic substitution. Compounds 3 and 4 were synthesized from the reaction of 1 with 2. Compounds 6, 7 and 8 were synthesized from reaction of 1 with 5. Compounds 10 and 11 were obtained from the reaction of 1 with 9. Compounds 13 and 14 were synthesized from the reaction of 1 with 12. Compounds 16 and 17 were obtained from the reaction of 15 with 2. Photochemical and electrochemical properties of N-, SO O-substituted quninone compounds were determined by using fluorescence spectroscopy and cyclic voltammetry. Crystal structure of 2-(7-sulphanyl-4-methyl-coumarinyl)-3-(1-ethoxy)-1,4-naphthoquinone 13 was determined by X-ray diffraction method.

One-pot synthesis, characterization, and antioxidant capacity of sulfur- and oxygen-substituted 1,4-naphthoquinones and a structural study

“…The cyclo ring containing sulfur and The double bond distance of C2-C3 was 1.357(2) Å in 8, which was smaller than expected due to substituents such as (=O). The double bond length of the quinone moiety agreed well with corresponding distance in similar compounds [4,29].…”

“…The synthesis, spectroscopic data ( 1 H, 13 C NMR, MS, UV, FT-IR), elemental analysis, and melting points of compounds 8 [19], 14 [20], and 15 [21] were reported in earlier studies. The antioxidant activity of all known (8,14,15) and unknown (4)(5)(6)(7)(9)(10)(11)(12)(13) compounds were investigated using the CUPRAC and DPPH methods, respectively. In this study, the crystal structure was solved as first for compound 8 by X-ray method.…”

“…The constitution of substituted naphthoquinone compounds is a result of a Michael-type addition to 2,3-dichloro-1,4naphthoquinone (1) followed by chloride elimination to afford a quinonyl intermediate that then reacts with the related nucleophile to yield the final products [1][2][3]. Heterocyclic compounds bearing 1,4-naphthoquinones have long been the focus of synthetic chemistry due to their broad spectrum of applications in biological, pharmaceutical, and material science areas [4]. In the present study, we used the technique of one-pot multicomponent reaction to obtain the compounds containing substantial elements of all the reactants such as 6 and 12.…”

Design, Synthesis, Biological Evaluation, and Antioxidant and Cytotoxic Activity of Heteroatom-Substituted 1,4-Naphtho- and Benzoquinones

“…In addition, a third lower energy transition appeared as a broad band in the visible region between 455 and 512 nm for 4a, 7a, 9a, b, 10 and 12. This absorption is typical of N-substituted quinones 22,23) and is assigned to charge-transfer transitions and weak n-π* transitions of the carbonyl group in the quinone unit. 24) Mono(thio)-substituted naphthoquinone compounds containing chlorine atom were not observed potentially due to the decreased thiol amount in the medium of the reaction, while mono(thio)-substituted naphthoquinone containing ethoxy group (3-position) compounds were obtained successfully.…”

Untitled

“…These anticancers have a great impact on the living cell because they are good electron acceptors which able to accept one or two electrons to form the corresponding radical anion or dianion species, and also have acid-base properties. They are effective inhibitors of DNA topoisomerase, and it is generally known that the cytotoxicity of quinone analogues results from the inhibition of DNA topoisomerase II [1], [2], [3] .1,4-naphthoquinones have a biological activities as well as antifungal, antibacterial, and anticancer activities, they interfere with electron transport and oxidative phosphorylation processes and play roles in enzyme inhibition, and DNA cross linking [4] .…”