90 A.] 



a-HYDROJUGLONE 



167 



heating to 600-800 with the metallic 

 hydroxide (Bradley and Jacobs, Germ. 

 Pat. 125936 of 1898; Ch. Centr. 1902, 



1, 77)- V 



Conversion of Naphthalene into 

 Hydrojuf/lone. 



By oxidation with chromic acid in 

 acetic acid naphthalene is converted 

 into a-naphthaquinone (Groves, Journ. 

 Ch. Soc. 26, 209 ; Plimpton, Trans. 

 37, 634; Japp and Miller, Ibid. 39, 

 22O ; by electrolytic oxidation, De Bot- 

 tens, Zeit. Elektroch. 8, 673). The 

 latter on standing in dilute sodium hy- 

 droxide solution in presence of air gives 

 the 5-a-hydroxyquinone = juglone 

 (Kowalski, Ber. 25, 1659), and this on 

 reduction yields hydrojuglone (Mylius, 

 Ber. 17, 2412; 18, 463 ; 2567). 



Naphthalene on sulphonation under 

 appropriate conditions gives (with i : 6-) 

 the i : 5-disulphonic acid (Armstrong, 

 Ber. 15, 200 ; Armstrong and Wynne, 

 Proc. Ch. Soc. 2, 231; 3, 42, and 146; 

 Bernthsen and Semper, Ber. 20, 934; 

 Bernthsen, Ber. 22, 3327). The latter 

 on fusion with alkali yields i : 5-dihy- 

 droxynaphthalene (Armstrong and 

 Wynne, Proc. Ch. Soc. 3, 43 ; Bernth- 

 sen and Semper, loc. cit. ; Erdmann, 

 Ann. 247, 306), and this on oxidation 

 with chromic acid mixture gives 5- 

 hydroxy-a-naphthaquinone, which can 

 be treated as above. 



Ornaphthalenemaybenitrated and the 

 a-nitronaphthalene sulphonated, when 

 the I : 5-nitrosulphonic acid is formed 

 (withotherisomerides)(Laurent,Ann.72, 

 298 ; Comp. Rend. 31, 537 ; Schmidt 

 and Schaal, Ber. 7, 1367; Palmaer, 

 Ber. 21, 3260; Erdmann, loc. cit.; Cleve, 

 Bull. Soc. [2] 24, 506). The latter 

 gives i : 5-naphthylaminesulphonic acid 

 by reduction (references as before, and 

 Schoellkopf Anilin Co., Germ. Pat. 

 40571 of 1885; Ekbom, Ber. 23, 

 1118; Bernthsen, Ibid. 3088; Schultz, 

 Ber. 20, 3158; Erdmann, Ibid. 3185; 

 Ann. 247, 306 ; 275,192; 262). This 

 aminosulphonic acid by the diazo-method 

 is converted into i : 5-naphtholsulphonic 

 acid (Cleve, loc. cit. ; Schultz, Ber. 20, 

 3161; Erdmann, loc. cit.} } which on 



fusion with potash gives i : 5-dihydroxy- 

 naphthalene (Cleve, loc. cit. ; Ewer 

 and Pick, Germ. Pat. 41934 of 1887). 

 The latter can be converted into juglone, 

 &c., as above. 



Or naphthalene- a -sulphonic acid can 

 be nitrated and the i : 5-nitrosulphonic 

 acid (which is formed with the i : 4 and 

 I : 8 isomerides) reduced and converted 

 as above (Cleve, loc. cit. ; Schoellkopf 

 Co., loc, cit. ; Cleve, Ber. 23, 958 ; 

 Bernthsen, Ibid. 3088 ; Erdmann and 

 Silvern, Ann. 275, 230). 



Or naphthalene can be converted into 

 a-nitronaphthalene and a-naphthylam- 

 ine. The latter (or its acetyl-deriva- 

 tive) gives (with other isomerides) the 

 I : 5-aminosulphonic acid on sulphona- 

 tion (Witt, Ber. 19, 578 ; Lange, Ber. 

 20, 2940 ; Schultz, Ibid. 3158 ; Erd- 

 mann, Ibid. 3185 ; Ann. 247, 306 ; 

 275, 192; 262; Mauzelius, Ber. 2O, 

 3401 ; Ewer and Pick, Germ. Pat. 

 42874 of 1887), and this sulpho-acid can 

 be treated as above. 



The i : 8-nitrosulphonic acid obtained 

 by the nitration of naphthalene-a-sul- 

 phonic acid as above gives the i : 8- 

 aminosulphonic acid on reduction 

 (Schoellkopf Co., loc. cit. ; Schultz, Ber. 

 20, 3158 ; Erdmann, Ann. 247, 306 ; 

 275, 262 ; Bernthsen, Ber. 23, 3088), 

 and this by the diazo-reaction gives the 

 i : 8-sultone (references as before). The 

 latter on fusion with potash yields i : 8- 

 dihydroxynaphthalene (Erdmann, loc. 

 cit.}, and this on oxidation with chromic 

 acid mixture gives juglone (Bernthsen 

 and Semper, Ber. 20, 939). 



Or the i : 8 -aminosulphonic acid on 

 fusion with alkali gives i : 8-amino- 

 naphthol (Bad. An. Sod. Fab., Germ. 

 Pat. 55404 of 1889; Ber. 24, Ref. 

 481). The latter on combination with 

 diazosulphanilic acid gives an azo-com- 

 pound which on reduction yields i : 4- 

 diamino - 8 - naphthol, and this gives 

 juglone on oxidation with ferric chloride 

 (Friedlander and Silberstern, Monats. 

 23, 



NOTE : Further references to processes for 

 obtaining i : 8-aminonaphthol or its generators 

 are given in Germ. Pats. 54662 ; 62289 ; 77937 > 

 84951 and 112778 of the Bad. An. Sod. Fab. ; 

 Germ. Pats. 71836; 75055; 753175 8o668 and 



