69 A-M.] 



CATECHOL 



141 



phonic acid fused with alkali (Ibid. 

 643 ; Degener, Journ. pr. Ch. [2] 20, 

 308). 



Catechol is among- the products of 

 the fusion of phenol with caustic soda 

 (Earth and Schreder, Ber. 12, 419); 

 and also among the products of the 

 electrolysis of a solution of phenol in 

 presence of magnesium sulphate and 

 acid carbonate by an alternating current 

 (Drechsel, Journ. pr. Ch. [2] 29, 249). 

 Catechol is among the products of the 

 action of hydrogen peroxide on phenol 

 (Martinon, Bull. Soc. [2] 43, 156). 



[B.] Salicylic acid Vol. II] when 

 iodised by various methods gives, among 1 

 other products, an iodosalicylic acid, 

 which on rapid heating- yields an iodo- 

 phenol, from which catechol can be 

 obtained as above (Kolbe and Laute- 

 mann, Ann. 115, 157; Lautemann, Ann. 

 120, 299 ; Hlasiwetz and Weselsky, 

 Ber. 5, 380; Ann. 174, 99; Liechti, 

 Ann. Suppl. 7, 129; Demole, Ber. 7, 

 1437 ; Fischer, Ann. ISO, 346 ; Birn- 

 baum and Reinherz, Ber. 15, 458 ; 

 Miller, Trans. Ch. Soc. 41, 406). 



Or salicylic acid may be nitrated 

 (Hiibner, Ann. 195, 6; 31; Schau- 

 mann, Ber. 12, 1346 ; Deninger, Journ. 

 pr. Ch. [2] 42, 551 ; Hirsch, Ber. 33, 

 3238), the 3-nitrosalicylic acid reduced, 

 the NH 2 -group replaced by iodine by 

 the diazo-method, and the 3-iodosali- 

 cylic acid fused with potash so as to 

 form catechol-o-carboxylic acid, which 

 on dry distillation gives catechol (Miller, 

 loc. cit.J. 



[C.] Benzole acid [Vol. II] gives 

 catechol among the products of its 

 fusion with potash (Hlasiwetz and 

 Barth, Ann. 130, 352; 134, 282). 



[D.] Protocatechuic acid [Vol. II] on 

 dry distillation gives catechol (Strecker, 

 Ann. 118, 285) ; also by fusion with 

 alkali (Barth and Schreder, Ber. 12, 

 1258). 



[E.] Piperonylic acid [Vol. II] when 

 heated with water at 210 gives catechol 

 (Fittig and Remsen, Ann. 159, 143). 



[P.] Feratric acid [Vol. II], when 

 heated with dilute hydrochloric acid, 

 gives a mixture of vanillic (3-methoxy- 

 protocatechuic) acid and the 4-meth- 

 oxy isomeride (Tiemann, Ber. 8, 514). 



Vanillic acid on distillation with lime 

 yields guaiacol (catechol methyl ether) 

 (Rid. 1123), an d tins, on heating- with 

 aqueous hydriodic acid or by the action 

 of aluminium chloride, gives catechol 

 (Miiller, Jahresber. 1864, 525 ; Gorup, 

 Ann. 143, 166; Baeyer, Ber. 8, 153; 

 Tiemann and Koppe, Ber. 14, 2017; 

 W. H. Perkin, junr., Trans. Ch. Soc. 57, 

 587 ; Hartmann and Gattermann, Ber. 

 25, 35.32). Or veratric acid on distilling- 

 its barium salt with baryta gives veratrole 

 (Merck, Ann. 108, 60 ; Koelle, Ann. 

 159, 243 ; Tiemann, Ber. 14, 2016), 

 which by heating with alcoholic potash 

 at 180-190 yields guaiacol (Bouveault, 

 Bull. Soc, [3] 19, 75). The latter can 

 be converted into catechol as above. 



[G.] Vanillin [121] on oxidation by 

 moist air gives vanillic acid (Tiemann, 

 Ber. 8, 1123), which can be converted 

 into guaiacol and catechol as above. 



Or vanillin can be converted into 

 acetferulai'c acid, oxidised by potassium 

 permanganate to acetvanillic acid, hy- 

 drolysed to vanillic acid (Tiemann, 

 Ber. 9, 420), and then treated as 

 above. 



[H.] Glycuronic acid [Vol. II] on 

 long boiling with potash solution gives 

 (with oxalic acid, &c.) catechol (Thier- 

 felder, Zeit. physiol. Ch. 13, 280). 



{!.] Besorcinol [70] gives catechol 

 among- other products when fused with 

 caustic soda (Barth and Schreder, Ber. 

 12, 504). 



[J.] Anisic acid [Vol. II] gives ani- 

 sole on distillation with baryta (Cahours, 

 Ann. 41, 69), and this on nitration yields 

 (with p-) o-nitroanisole, and by reduc- 

 tion anisidine (Miihlhauser, Ann. 207, 

 237 ; 239 ; Brunck, Zeit. [2] 3, 205). 

 The latter by the diazo-reaction gives 

 guaiacol (Kalle & Co., Germ. Pat. 95339 

 of 1 896, and under A above), from which 

 catechol can be obtained as under P. 



[K.] llydrojuglone [90] gives catechol 

 among the products of its fusion with 

 potash (Mylius, Ber. 18, 475). 



[L.] Dextrose [154] is said to give 

 catechol among the products formed 

 when heated with water under pressure 

 (Munk, Zeit. physiol. Ch. 1, 362). 



[M.] Mannose [156] gives (with lactic 

 acid) catechol on boiling with caustic 



