238 



AROMATIC ALDEHYDES AND KETONES [144 c-145 B. 



of the product with water (Thorner and 

 Zincke, Ber. 10, 1479). 



Anthracene is converted into anthra- 

 quinone by oxidation (Laurent, Berz. 

 Jahresber. 16, 366; Ann. Chim. [2] 

 60, 220; 72, 415; Ann. 34, 287; 

 Anderson, Journ. Ch. Soc. 15, 44; Ann. 

 122, 301 ; Graebe and Liebermann, 

 Ann. Suppl. 7, 285 ; Kopp, Jahresber. 

 1878, 1 1 88; Darmstadter, Germ. Pat. 

 109012 of 1897; Ch. Centr. 1900, 2, 

 150- 



Anthracene and anthraquinone give 

 m-hydroxyantbraquinone as follows : 

 Anthracene by the action of bromine 

 gives dibromanthracene bromide (An- 

 derson, loc. cit.; Graebe and Liebermann, 

 loc. cit. 275), and this on heating at 

 200 yields tribromanthracene. The 

 latter on oxidation (with chromic acid in 

 acetic acid) gives 2-bromanthraquinone 

 (G. and L. loc. cit. 290), and this yields 

 2-hydroxyanthraquinone on fusion with 

 potash (Ibid. Ann. 160, 141 ; Suppl. 7, 

 290 ; 212, 25). 



Anthraquinone on sulphonation gives 

 (with disulpho-acid) 2-sulpho-acid (Ibid. 

 Ann. 160, 131)' an( l ^hi yi^s the 2- 

 hydroxyquinone by potash fusion (Ibid. 

 141 ; Simon, Ber. 14, 464 ; Lieber- 

 mann, Ann. 212, 25 : see also A. G. 

 and W. H. Perkin, junr., Trans. Ch. Soc. 

 47, 680). Or the solution of the sulphonic 

 acid (salt) may be heated with lime and 

 water under pressure at 160 (Meister, 

 Lucius, and Briining, Germ. Pat. 106505 

 of 1898; Ch. Centr. 1900, 1, 741). 



Or the 2-sulphonic acid heated with 

 excess of aqueous ammonia at 1 90 gives 

 2-aminoanthraquinone (Perger, Ber. 12, 

 1567 : see also Bourcart,/foV/. 1418), and 

 this yields the 2-hydroxyquinone by the 

 diazo-method (Perger, loc. cit. 1569). 



By the action of nitric acid on di- 

 bromanthracene (Glaus and Hertel, Ber. 

 14, 978), or on anthraquinone (Bottger 

 and Petersen, Ann. 166, 147), the a- 

 nitro-quinone is formed, and this on 

 reduction with potassium sulphydrate 

 gives the a-amino-quinone (Ibid. 149 : 

 see also Glaus and Hertel, loc. cit. 979). 

 The latter yields the m-hydroxyquinone 

 by the diazo-method (B. and P. loc. cit. 



[D.] From alizarin [145] by treat- 

 ment with alkaline stannite (Lieber- 

 mann and Fischer, Ber. 8, 975). Or 

 through a-alizarinamide by heating 

 alizarin with aqueous ammonia at 200 

 (Liebermann, Ann. 183, 207), and 

 elimination of the NH 2 -group by the 

 diazo-method (Ibid. 208). 



145. Alizarin ; 

 1 : 2-Diliydroxyanthracmiiioiie. 



HO 



,OH 



NATURAL SOURCES. 



Occurs as the glucoside ruberythric 

 acid (C 26 H 28 O 14 ) in madder from the 

 root of Svdia tinctoria (Robiquet and 

 Colin, Ann. Chim. [2] 34, 225 ; Runge, 

 Journ. pr. Ch. 5, 362 ; Schunck, Ann. 

 66, 174; 201; 81, 336; 87, 344; 

 Phil. Mag. [4] 5, 410; 495; 12, 200 ; 

 270; Journ. pr. Ch. 59, 465; Debus, 

 Ann. 66, 351 ; Wolff and Strecker, 

 Ann. 75, i ; Rochleder, Ber. 3, 295 ; 

 Ann. 80, 321; 82, 205; Wartha, Ber. 

 3, 545 ;. 673 ; Willigk, Ann. 82, 339 ; 

 Rosenstiehl, Ann. Chim. [5] 18, 235 ; 

 Comp. Rend. 88, 1194; Wurtz, Comp. 

 Rend. 96, 465 ; Liebermann, Ber. 20, 

 2241 ; Bergami, Ibid. 2247). 



Alizarin occurs also in Chay root 

 from Oldenlandia ^lmbellata (see under 

 m-hydroxy anthraquinone [144] ; A. G. 

 Perkin and Hummel, Trans. Ch. Soc. 

 63, 1167). 



SYNTHETICAL PROCESSES. 



[A.] From cateckol [69] and phUalie 

 anhydride (see under benzyl alcohol 

 [54 ; B,]), a mixture of these com- 

 pounds giving alizarin when heated 

 with strong sulphuric acid (Baeyer and 

 Caro, Ber. 7, 972). 



[B.] Anthracene [144; C] is chlori- 

 nated or brominated, and the product 

 oxidised to dichlor- or dibromanthra- 



