Intermediates in the cleavage of endoperoxides

Abstract

The decomposition of anthracene endoperoxides has been investigated under various conditions. Thermolyses proceed via radical intermediates and afford anthracenes and rearrangement products, depending on the substitution pattern. Interestingly, not only the O–O but also the C–O bond can be cleaved homolytically. Under basic conditions fragmentations take place, affording anthraquinone, and reactive oxygen species. This mechanism explains the often observed decomposition of endoperoxides during work‐up. Finally, an acid‐catalyzed cleavage has been observed under release of hydrogen peroxide. The results should be interesting for the mechanistic understanding of peroxide decomposition and the endoperoxides might serve as mild sources of reactive oxygen species for future applications. Copyright © 2016 John Wiley & Sons, Ltd.

Photooxygenation of oxygen‐substituted naphthalenes

“…Subsequent reaction under acidic conditions affords 1,4‐naphthoquinone ( 4 ) as the final product (Scheme ). Such a mechanism is in accordance to our very recent studies on the stability of EPOs derived from anthracenes …”

Recognition Properties and Self‐assembly of Planar [M(2‐pyridyl‐1,2,3‐triazole)2]2+ Metallo‐ligands

“…One cage also interacted in solutionw ith anthracenyl guests.T he metallo-ligand Pt 1 also recognised anthracene. This piqued our interesti nt he use of Pd 1 and Pt 1 as hosts for planar aromatic guests.H erein we investigatet he binding capabilitieso ft he cationic hosts in solution with two organic guests( anthracene (1)a nd 9,10-bis(2phenylethynyl)-anthracene (2) [27] )a nd one neutralp latinum(II) complex( [((E)-2-((2-oxidobenzylidene)amino)phenolate)(DM-SO)platinum(II)] (3), [28] Figure 1c). We investigated the self-as-sembly properties of the metallo-ligands and host-guest systems with silver(I) ions.…”

Synthesis of 5α,8α‐Ergosterol Peroxide 3‐Carbamate Derivatives and a Fluorescent Mitochondria‐Targeting Conjugate for Enhanced Anticancer Activities

“…Endoperoxides (EPOs) are cyclic organic compounds, with an OÀOs ingle bond as ap eroxidic bridge. [1] EPOs include 1,2-dioxanes, 1,2,4-trioxanes,a nd 1,2,4,5-tetraoxanes, all of which possesst he critical peroxide linkage. [2] They play an important role in drug synthesis as well as in medicine [3] andr epresent the central part of artemisinin, an outstanding antimalarial drug that was honored with the Nobel Prize in Medicinei n 2015.…”

“…[9] Among natural EPOs, 1,2-dioxanes are the most frequent constituents of naturally occurring endoperoxides,s uch as sterol 5a,8a-endoperoxides, whicha re important activel ead compounds in drugd iscovery. [10] Ergosterol peroxide (5a,8aepidioxiergosta-6,22-dien-3b-ol, EP, 1)( Figure 2) is am ember of ac lass of fungals econdary metabolites of sterol 5a,8a-endo-Inspired by the significant anticancer activity of our previously screened natural ergosterol peroxide (1), we synthesized and characterized aseries of novel ergosterol peroxide 3-carbamate derivatives. Thea ntiproliferative activities of the synthesized compounds against humanh epatocellular carcinomac ells (HepG2, SK-Hep1) and human breast cancer cells( MCF-7, MDA-MB231) were investigated.…”