34425-60-0

Upstream product

• 18855-92-0 3-chlorojuglone 
• 75436-68-9 2-methyl-1-trimethylsiloxy-1-methoxy-1,3-butadiene 
• 107960-75-8 2-methyl-1,8-dimethoxy-9,10-anthracenedione 
• 107960-83-8 2-bromomethyl-1,8-dimethoxy-9,10-anthracenedione 
• 6407-55-2 1,8-dimethoxy-9,10-anthracenedione 
• 5539-66-2 1-hydroxy-8-methoxyanthraquinone 
• 131656-57-0 Acetic acid 1,8-dihydroxy-9,10-dioxo-9,10-dihydro-anthracen-2-ylmethyl ester 
• 51996-00-0 1-hydroxy-8-methoxy-2-methyl-9,10-anthracenedione 

Relevant academic research and scientific papers

Synthesis and bioactivities of naturally occurring anthraquinones: Isochrysophanol, isozyganein, ω-hydroxyisochrysophanol and morindaparvin

Isochrysophanol, isozyganein, ω-hydroxyisochrysophanol, and morindaparvin are naturally occurring substituted anthraquinones. We report the synthesis of these compounds as well as selected biological activities.

Novel anthraquinone inhibitors of human leukocyte elastase and cathepsin G

A large series of variously substituted anthraquinones has been synthesized and assayed for inhibitory capacity against human leukocyte elastase (HLE) and cathepsin G (CatG), two serine proteinases implicated in diseases characterized by the abnormal degradation of connective tissue, such as pulmonary emphysema and rheumatoid arthritis. It was found that 2-alkyl- 1,8-dihydroxyanthraquinone analogues are competitive inhibitors of HLE with IC50 values ranging from 4 to 10 μM, and also inhibit CatG with IC50 values ranging from 25 to 55 μM. Consequently, analogues containing the 2- alkyl-1-hydroxy-8-methoxyanthraquinone substitution pattern inhibit HLE to the same magnitude as for the compounds above, but show very little inhibition of CatG. Anthraquinones containing long, hydrophobic n-butyl carbonate moieties in the 1- and 8-positions in conjunction with a third hydrophobic substituent in the 2- or 3-position are highly selective for HLE, with K(i) values in the range of 10-7 M. All of the inhibitors described are completely reversible, with no evidence of acyl-enzyme formation detected.

Substituent Effects upon Peak Potentials and Reductive Cleavage Rate Constants of Hydroxy- and Methoxy-Substituted 9,10-Anthraquinones in 50percent Aqueous CH3CN: Do They Correlate?

A variety of hydroxy- and methoxy-substituted 2-(acetoxymethyl)-9,10-anthraquinones (2a-7a) were reduced electrochemically and with dithionite (S2O42-) in 50percent aqueous CH3CN buffers over a wide pH range.Good to excellent yields of their corresponding reductive cleavage products, the substituted 2-methyl-9,10-anthraquinones 2b-7b, were obtained from most of these anthrachinone acetates, but only at higher pH.Rate constants for the reaction of 2-(acetoxymethyl)-9,10-anthraquinone (1a) with excess dithionite ranged from 1.0 x 10E-4 s-1 at pH values less than 7 to 4.0 x 10E- 4 s-1 at a pH of 10, demonstrating that loss of acetate occurs in the rate-determining step and that cleavage occurs slower via the anthrahydroquinone of 1a than the conjugate base of the anthrahydroquinone.Substituent effects upon the reductive cleavage process were determined by measuring rate constants for those acetates that react cleanly with dithionite at pH 8.These effects, which are rationalized on the basis of resonance theory and intramolecular H bonding, correlate fairly well with the peak potentials (Ep) of the reductive cleavage products of these acetates.Thus, electron-donating substituents on an anthraquinone acetate not only make it more difficult to reduce resulting in a more negative Ep but also enhance the rate of acetate cleavage in the corresponding anthrahydroquinone.

Regiospecific Addition of Monooxygenated Dienes to Halo Quinones

In spite of their decreased polarity with respect to previously studied electron-rich analogues, monooxygenated dienes also react regiospecifically with halo quinones.The corresponding adducts can easily be aromatized on silica gel to isomeric polysubstituted naphthoquinones of unambiguous structure and therefore provide ready access to substrates for subsequent regiospecific annulations.The scope of this approach is illustrated by advantageous syntheses of several natural products: chimaphilin, 6-methylalizarin, 6-methylxantopurpurin, and barleriaquinone.The adductscan also give rise to a series of products in which the oxygen function of the dienes is preserved as a hydroxyl group in the quinone.To this end adducts derived from 1-oxygenated dienes and halo quinones were oxidized effectively with Jones reagent while those obtained from the 2-oxygenated isomers responded better to manganese dioxide.Relative positions of substituens in the adducts were readily confirmed by comparison of some of the hydroxylated oxidation products with known compounds of unambiguous structure.The method is again illustrated by the ready synthesis of a number of natural products including plumbagin, soranjidiol, isochrysophanol and its 8-methyl ether, and isozyganein and its 5-methyl ether.

REACTIONS OF KETENE ACETALS-14; THE USE OF SIMPLE MIXED VINYLKETENE ACETALS IN THE ANNULATION OF QUINONES

α,β- and β,γ-unsaturated esters can be converted by strong base and chlorotrimethylsilane to the corresponding mixed vinylketene acetals which are shown to be particularly useful and generally applicable reagents for the regiospecific annulation of halogenoquinones.The reaction proceeds readily with a variety of substrates including benzoquinones.