2- Methylanthraquinone

The mechanism of photoenolization in 1-methylanthraquinone has been studied in detail (Gritsan, N. P. Khmelinski, I. V. Usov, . M., J. Am. Chem. Soc., 1991, 113, 9615). The reaction was found to occur in both the singlet and triplet (nn ) states. Develop a Dauben-Salem-Turro state correlation diagram for the photochemical step and, on the basis of your diagram, discuss the efficiency of the reaction... 

Methylanthraquinone (II) was synthesized by fusing o-(o-toluene)benzoic acid and poly-phosphoric acid and cooling the mixture with the addition of some... 

The study of photochromic transformations of 1-methylanthraquinone and its deuterium analog by means of laser photolysis over a wide temperature range30... 

One can see from Table 7.1 that the quantum yield of photolysis of alkyl-substituted anthraquinones only slightly depended on the replacement of the methyl group by the ethyl or isopropyl group.26 However, it decreased drastically after the introduction of electron-donor substituents in 3- or 4-positions of the anthraquinone ring.17 Quantum yields of phototransformations of l-arylcyanomethyl-9,10-anthra-quinones were found to be substantially lower (by two orders of magnitude) than for 1-methylanthraquinone.36... 

The rate constant of thermal bleaching of derivatives of 1-methylanthraquinone depended on the nature of the solvent. Table 7.14 shows that it decreased by several orders or magnitude as the proton-donor ability increased. 

N.P. Gritsan, V.A. Rogov, N.M. Bazhin, V.V Russkikh, and E.P. Fokin, Study of photochromic transformations for 1-methylanthraquinone and l-oxy-4-methylanthraquinone by method of low-temperature and flash photolysis, Teor. Eksp. Khim. 15, 290-296 (1979) (Russ.). 

N. P. Gritsan and N. M. Bazhin, Influence of the substituent nature on the mechanism and photolysis efficiency for derivatives of 1 -methylanthraquinone, Izv. Sib. Otd. Akad, Nauk SSSR, Ser. Khim. Nauk N7, 138-143 (1979) (Russ.). 

The noteworthy N-demethylation of aclacinomycin A [40] or the oxidation of 1-methylanthraquinone [41] probably proceeds by mechanistically related photooxidation processes [42]. For the photooxidation of natural rubiginones (OH at C-1) see [5]. 

In addition to hydroxyanthraquinones such as alizarin, which is derived from shikimate, glutamate and mevalonate precursors, higher plants produce some polyketide anthraquinones identical to those of microbial origin. Of particular interest is the cooccurrence in root extracts of Aloe species of the 2-methylanthraquinone chiysophanol (63) and the isomeric 1-methylanthraquinone aloesaponarin II (64), since in microorganisms 63 has only been isolated fi om fungal species whereas 64 is the product of a recombinant streptomycete (Figure 7). 

Synonyms 2-Anthracenecarboxylic acid, 7-a-D-glucopyranosyl-9,10-dihydro-3,5,6,8-tetrahydroxy-1 -methyl-9,10-dioxo- 2-Anthracenecarboxylic acid, 7-p-D-glucopyranosyl-9,10-dihydro-3,5,6,8-tetrahydroxy-1-methyl-9,10-dioxo- Cl 75470 Cl Natural red 4 Cochineal tincture 7-a-D-Glucopyranosyl-9,10-dihydro-3,5,6,8-tetrahydroxy-1 -methyl-9,10-dioxo-2-anthracenecarboxylic acid 7-Glucopyranosyl 3,4,5,8-tetrahydroxy-1-methylanthraquinone-2-car1)oxy acid Natural red 4 Definition Naturally derived color from the insect, Coccus cacti, the essential constituent of carmine Empiricai C22H20O13... 

Glucopyranosyl 3,4,5,8-tetrahydroxy-1 -methylanthraquinone-2-carboxy acid. See Carminic acid... 

Glucopyranosyi-3,4,5,8-tetrahydroxy-1-methylanthraquinone-2-carboxylic acid. Carminic acid. Natural red 4. C. I. 75470. Cochineal [1260-17-9]... 

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