Anthrone derivatives

Viljoen et al. (2002) have described the occurrence of a new anthrone derivative, which they named homonataloside B, from 14 species of Aloe (of the 380 tested). Species containing this compound, a hitherto unknown diglycoside, were obtained from scattered sites in East Africa, the Horn of Africa, and southern parts of the Arabian Peninsula. The compound was not observed in any of the species native to Madagascar. 

Photochemical isomerizations by intramolecular 4n + An cycloaddition of carbon oxygen linked bichromophoric anthracenes to give oxetane derivatives have not been reported yet. Upon irradiation (X > 400 nm) in either toluene or ethyl acetate, the methoxycarbonyl substituted carbon oxygen linked bichromophoric anthracene 14 indeed isomerizes smoothly and efficiently (cp — 0.45). However, the two products, obtained in an approximate ratio of 5 1, are anthrone derivatives 15 and 16 whose formation can be rationalized by migration of the anthryloxy moiety [60], An analogous photolytic rearrangement has been found for 9-anthryloxy substituted dianthrylethylenes (see Section III.A). 

Di-9-anthrylethane and related derivatives topology, 144 9-anthraldehyde azines, 153 anthrone derivatives, 148 bis-a-9-anthrylmethyl ethers, 151 dianthrylacetone, 149... 

Chiral bicyclic guanidine (221) has been identified as an excellent catalyst for reactions between anthrones (219) and various dienophiles, such as (220). The catalyst can tolerate a range of substituents and substitution patterns, making several anthrone derivatives suitable for this reaction. Both Diels-Alder and Michael adducts were obtained in excellent yields, high regioselectivities, and high enantioselectivities (<99% ee). This is the first case of a highly enantioselective base-catalysed anthrone Diels-Alder reaction.263... 

Anthralin, an anthrone derivative of chrysarobin, was introduced under the name dithranol in Great Britain decades ago. Chronic plaque-type and guttate psoriasis respond better than other variants to anthralin treatment. Topical anthralin, particularly with UV light, is long established as an effective approach to the treatment of psoriasis. ... 

Detection of anthrone derivatives (grey-blue zones, vis). 

Homonataloin is not hydrolyzed by dilute acid, and, on oxidation with sodium metaperiodate in the dark at 0°, it consumes two moles only of oxidant per mole, with the production of some formic acid (unstated amount). Ozonolysis of homonataloin gives a mixture of D-glucose and D-arabinose in good yield, showing it to be a D-glucose derivative. The ultraviolet and infrared absorption spectra of homonataloin reveal that it is an anthrone derivative, and the D-glucopyranosyl residue is placed at C-10 since homonataloin does not condense with p-nitrosodimethylaniline. It therefore follows that homonataloin has the structure (14). 

Acrolein, crotonaldehyde, and methacrolein were separated as their anthrone derivatives on a C g column (2 = 405nm, ex 480nm, em) using a 60/40 acetonitrile/water mobile phase [918]. Elution was complete in 10 min and peak shines were very good. Detection limits of 5 ppb and linear concentration ranges from 20 ppb to 14 ppm were reported. 

In 2008, Gobel et al. reported the Diels-Alder reaction of TV-substituted maleimides with anthrone derivatives which constituted the first asymmetric catalysis by a bisoxazoline in the absence of any metal ions. These cycloadditions led to the corresponding cycloadducts in excellent yields and moderate enantioselectivities (<70% ee), as shown in Scheme 6.9. 

Emodins with both aromatic rings hydroxylated are synthesised exclusively by the polyketide pathway as octaketides. Biosynthesis of bianthrones and other condensed emodin derivatives occurs by one-electron oxidation of anthrone derivatives (anthranols) to radicals, which are joined to form bianthrones. 

The 9-anthrone derivatives (29) (from the heartwood of Cassia garrettiana Craib), (30), and (31) (from the bark of Rhamnus kurshianus) and several... 

Hsieh et al. (1976a) attempted to incorporate radioactivity into aflatoxin Bi from four tritiated anthraquinone and anthrone derivatives to simulate the proposed C18 compounds (Biollaz et al., 1970). None of the four compounds was readily convertible into aflatoxin Bi. These findings clearly indicated that a Cig naphthacene precursor is no longer tenable. 

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