P-Methylanthraquinone

Methylanthraquinone. Use 10 5 g. of p-toluyl-o-benzoic acid (preceding Section) and 90 g. (46 ml.) of fuming sulphuric acid (20 per cent. SO3). RecrystaUise the product from alcohol in the presence of a little decolourising carbon. The yield of pure p-methylanthraquinone, m.p. 176°, is 7 - 5 g. 

Methyl n-amyl carbinol. 247, 254 Methyl n-amyl ketone, 482 Methylaniline (mono), pure, from commercial methylaniline, 562, 570 P-Methylanthraquinone, 728, 740 Methyl benzoate, 780, 781 p-Methyl benzyl alcohol, 811,812 Methyl benzyl ketone, 727, 735 Methyl y-bromocrotonate, 926, 927 2-Methyl-2-butene, 239 Methyl n-butyl carbinol, 247,255 Methyl n-butyl ether, 314 Methyl n-butyl ketone, 475, 481 4-Methylcarbostyril, 855 p-Methylcinnamic acid, 719 4-Methylcoumarin, 853, 854 Methyl crotonate, 926, 927 Methylethylacetic acid, 354, 358 Methylethylethynyl carbinol, 468 Methyl ethyl ketone, 335, 336 purification of, 172 Methyl n-hexyl ether, 314 Methyl n-hexyl ketone, 335, 336 Methyl n-hexyl ketoxime, 348 Methyl hydrogen adipate, 938 Methyl hydrogen sebacate, 938,939 4-Methyl-7-hydroxycoumarin, 834 Methyl iodide, 287 Methyl isopropyl carbinol, 247,255 Methyl 4-keto-octanoate, 936... 

Dimethylbutadiene and 1 4-naphthoquinone. 2 3-Di-methylanthraquinone. In a small round-bottomed flask, fitted with a reflux condenser, place a solution of 8 g. of freshly-distUled 2 3-dimethyl-butadiene (Section 111,147) and 8 g. of 1 4-naphthoquinone (Section IV,149) in 30 ml. of ethanol, and reflux for 5 hours. Keep the resulting solution in a refrigerator for 12 hours break up the crystaUine mass, filter, and wash with 5 ml. of alcohol. The yield of crude adduct, m.p. 147-149°, is 11-5 g. recrystaUisation from methanol raises the m.p. to 150°. 

Amino-2-methylanthraquinone 2-Amino-3-methylimidazo[4,5-/]quinoline (see IQ) 2-Amino-6-methyldipyrido[l,2-a 3, 2 -fil]imidazole (see Glu-P-1) 2-Amino-l-methyl-6-phenylimidazo[4,5-6]pyridine (see PhIP)... 

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 can be prepared by heating 2-p-toluoyl-benzoic acid with about 9 times its weight of oleum containing 20% S03. On dilution with water, and recrystallising from dilute acetic acid, pale yellow needles are obtained, M.P. 177°. (B., 41, 3632 J. pr. [ii], 33, 318 A., 311, 178). 

The aroylation of an aromatic system by reaction with phthalic anhydride under Friedel-Crafts conditions is described in Section 6.11.1, p. 1006. The cyclisation of the derived o-aroylbenzoic acid with polyphosphoric acid is a convenient route to substituted anthraquinones. The reaction is illustrated by the formation of 2-methylanthraquinone from o-(p-toluoyl)benzoic acid (Expt 6.132). 

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.). 

I Concerning the mononitration of 2-methylanthraquinone, see p. 227, as well as Locher and Fierz, Helv. Chim. Acta, 10, 642 (1927). 

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