Anthralin and its acetyl esters: spectroscopic properties and enzyme inhibitory activity

Wiegrebe, Wolfgang; Retzow, A; Plumier, E.

doi:10.1111/j.1365-2133.1981.tb00991.x

Cited by 6 publications

(4 citation statements)

References 4 publications

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“…In nonpolar aprotic solvents anthralin exists as the anthracenone tautomer exclusively, − whereas the 1,8,9-trihydroxyanthracene could only be identified in hexamethylphosphoric triamide . When bases are added or when anthralin is dissolved in polar aprotic solvents it is partially converted to its anion 1a , − which is the predominant form in basic solutions and in DMF. , On the basis of computational studies, the ionization site for anthralin was predicted to be at the 10-position . The formation of 7 is without precedence but can be rationalized in a straightforward manner as a process involving electrophilic substitution at the 10-position of the quite electron-rich, nucleophilic polyhydroxyanthracene anion 1a of anthralin thus formed in DMF.…”

Section: Resultsmentioning

confidence: 99%

Syntheses of Anthracenones. 3. Revised Preparative Route to 10-Benzoyl-1,8-dihydroxy-9(10H)-anthracenones

1996

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The acylation of anthralin (1,8-dihydroxy-9(10H)-anthracenone) with acetylsalicylic acid chloride in toluene and collidine was found to give the O-acylated product, rather than 10-(acetylsalicyl)anthralin. A procedure is described for benzoylation of anthralin in the 10-position which involves reaction of 1,8-diacetoxy-9(10H)-anthracenone with benzoyl chloride and sodium hydride in THF followed by hydrolysis of an intermediate enol ester. Furthermore, when benzoyl chloride and DMF were used for the acylation of anthralin, a Vilsmeier-type reaction was observed leading to a novel enamine derivative of anthralin which was hydrolyzed or benzoylated to an enol or enol ester, respectively.

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Section: Resultsmentioning

confidence: 99%

Syntheses of Anthracenones. 3. Revised Preparative Route to 10-Benzoyl-1,8-dihydroxy-9(10H)-anthracenones

1996

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“…The data in Table 1 clearly show that the deprotonated 1,8,9-trihydroxyanthracene is the active species for interaction with lo2 with high rates of reaction and quenching, and that there is no appreciable contribution from the neutral l,&dihydroxy-9-anthrone. It might be expected that under physiological pH conditions there would be only 3.0 5 0.7 D20-buffer small amounts of anion present, but binding to albumin leads to the formation of deprotonated anthralin (Kohen et al, 1986;Sa e Melo et al, 1983;Wiegrebe et al, 1981).…”

Section: Direct Determination Of Kr+kg From the Decay Rate Of 127 Fmmentioning

confidence: 99%

“…, 1983) where it exists as the anthrone tautomer exclusively (Avdovich and Neville, 1980;Geiger, 1974;Miiller et al, 1986). In polar aprotic solvents and in buffered bovine serum albumin solutions, it is partially converted to the trihydroxyanthracene anion (Wiegrebe et al, 1981); some of this form has also been detected in cytoplasm (Kohen et al, 1986). In basic solutions it exists mainly as the anion (Sa e Melo et al, .1983).…”

Section: Introductionmentioning

confidence: 99%

Kinetic Studies on Anthralin Photooxidation

Müller

Kanner

Foote

1990

Photochem & Photobiology

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The photooxidation of the antipsoriatic drug anthralin (1,8-dihydroxy-9-anthrone) has been studied by several kinetic techniques, including direct observation of 1O2 (1 delta g) luminescence at 1.27 microns. The rate of deactivation of 1O2 increases at higher pH, demonstrating that the trihydroxyanthracene anion is the reactive species. Direct determination of the rate constant of 1O2 deactivation (kR + kQ) in deuterated buffer systems by luminescence quenching gave a value of 3.0 x 10(8) M-1 s-1 for the anion; the neutral anthrone is unreactive. The rate constant for the neutral anthrone in benzene-d6 is 2.8 x 10(4) M-1 s-1. Competition experiments with tetramethylethylene in acetonitrile gave a rate constant for reaction alone (kR) of 2.1 x 10(8) M-1 s-1 for the anion.

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“…This oxidation process is initiated by proton elimination on C-10, the active centre of the molecule, resulting in the 10-anthranyl radical. This highly reactive anthralin free radical reacts efficiently with ox ygen to form an intermediate dithranolperoxy radical and then dithranolhydroperoxy radical in the chain reaction toward danthrone [12,13]. During this auto-oxidation process, reduction products of molecular ox ygen are also formed, such as singlet oxygen [14,15], superoxide radical anion [14] and hydroxyl radical [ 16].…”

Section: Chemical Structurementioning

confidence: 99%

Dithranol: A Review of the Mechanism of Action in the Treatment of Psoriasis vulgaris

Kemény¹,

Ruzicka²,

Braun‐Falco³

1990

Skin Pharmacol Physiol

102

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Dithranol is highly effective in the treatment of psoriasis. The drug inhibits keratinocyte hyperproliferation, granulocyte function and, in addition, may exert an immunosuppressive effect. Free radicals, histamine, eicosanoids and platelet-activating factor have been shown to be involved in dithranol-induced dermatitis, and the oxidation products of the drug are responsible for the staining. Our experimental data suggest that extracellularly generated oxygen free radicals are responsible for both the antipsoriatic and irritative effect of the drug. Furthermore, we could recently provide evidence that extracellularly generated superoxide anion radical also induces an active adaptation mechanism resulting in increased tolerance to dithranol upon repeated application. This adaptive process may explain the requirement for increasing dithranol concentrations to maintain the antipsoriatic efficacy, and also the beneficial effect of other antipsoriatic modalities such as UV-B on dithranol-induced dermatitis. The recognition of this adaptive mechanism may open future prospects to overcome some limitations concerning the practical use of dithranol.

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Anthralin and its acetyl esters: spectroscopic properties and enzyme inhibitory activity

Cited by 6 publications

References 4 publications

Syntheses of Anthracenones. 3. Revised Preparative Route to 10-Benzoyl-1,8-dihydroxy-9(10H)-anthracenones

Syntheses of Anthracenones. 3. Revised Preparative Route to 10-Benzoyl-1,8-dihydroxy-9(10H)-anthracenones

Kinetic Studies on Anthralin Photooxidation

Dithranol: A Review of the Mechanism of Action in the Treatment of Psoriasis vulgaris

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