75 C-76 A.] 



ORCINOL 



155 



The dihydroxyphenyltricarboxylic ester 

 (ethyl orcinoltricarboxylate) is also ob- 

 tained (with a ' lactone J ) by the action 

 of sodium ethoxide on an alcoholic 

 solution of acetonedicarboxylic ester 

 (Jerdan, Proc. Ch. Soc. 15, 151 ; Trans. 

 75, 808). Methyl acetonedicarboxylate 

 undergoes condensation to an orcinol 

 derivative more readily than the ethyl 

 ester (Dootson, Trans. Ch. Soc. 77, 

 1196). 



NOTE : Citric acid gives acetonedicarboxylic 

 acid when oxidised by potassium permanganate 

 at 30-35 (Deniges, Comp. Rend. 130, 32 ; Ann. 

 Chim. [7] 18, 41 3). 



Citric acid can also be converted into 

 dehydracetic acid by the action of acetic 

 anhydride on acetonedicarboxylic acid 

 (v. Pechmann, Ber. 24, 3600). Dehy- 

 dracetic acid can be converted into 

 orcinol as below under D. 



[D.] Acetoacetic ester [Vol. II] on 

 chlorination gives (with a-) y-chloraceto- 

 acetic ester (Haller and Held, Comp. 

 Rend. 108, 516; 111, 647; 114, 400, 

 452; Ann. Chim. [6] 23, 157: see 

 also Genvresse, Comp. Rend. 107, 687 ; 

 Ann. Chim. [6] 24, 46; Hantzsch, 

 Ber. 23, 2339 ; Hantzsch and Schiffer, 

 Ber. 25, 728) ; the corresponding y- 

 cyanacetoacetic ester obtained by the 

 action of potassiiim cyanide [172] on the 

 chloro-ester gives, on hydrolysis with 

 hydrochloric acid and alcohol, acetone- 

 dicarboxylic ester (Haller and Held, 

 Comp. Rend. Ill, 682), which can be 

 converted into orcinol as above under C. 



Or acetoacetic ester can, by the action 

 of heat, be converted into dehydracetic 

 acid (Geuther, Zeit. [2] 4, 655 ; Oppen- 

 heim and Precht, Ber. 9, 324 ; W. H. 

 Perkin, junr., Trans. Ch. Soc. 51, 489), 

 and the latter gives orcinol on heating 

 with baryta water or (better) with 

 syrupy caustic soda solution at 150 

 (Oppenheim and Precht, loc. cit. ; Collie, 

 Trans. Ch. Soc. 59, 183; Collie and 

 Myers, Ibid. 63, 124). 



Dehydracetic acid is formed also by 

 the action of pyridine on acetyl chloride 

 (Dennstedt and Zimmermann, Ber. 19, 

 76), or of triethylamine or ferric chloride 

 on acetyl chloride (Wedekind, Ch. Centr. 

 1900, 2, 561 ; Ann. 323, 246). 



[E.] From malonic acid [Vol. II] 



through acetonetricarboxylic and dicar- 

 boxylic acid (see under phloroglucinol 

 [86 ; E]), and then as above under C. 



76. Cresorcinol; 

 2 : 4-Dihydroxytohiene ; 

 Methyl-2 : 4-Phenediol. 

 CH, 



OH 



HO 



NATURAL SOURCE. 



The cresorcinol complex probably 

 exists in cyanomaclurin, which occurs 

 with morin in the wood of Artocarpus 

 integrifolia from India and Java (A. G. 

 Perkin and Cope, Trans. Ch. Soc. 67, 



939)- 



SYNTHETICAL PROCESSES. 



[A.] From toluene [54; A, &c.] 

 through p-toluidine, 2-nitro-4-toluidine 

 by nitration (Noelting and Collin, Ber. 

 17, 263), 2-nitro-4-cresol by the diazo- 

 method (Neville and Winther, Ber. 15, 

 2980; Knecht, Ann. 215, 87), 2-amino- 

 4-cresol by reduction (Knecht, loc. cit. 

 91 ; Wallach, Ber. 15, 2833), and the 

 diazo-reaction with the latter (Knecht, 

 loc. cit. 92). 



Or directly from toluene through the 

 2 : 4-disulphonic acid (Hakanson, Ber. 

 5, 1085 ; Gnehm and Forrer, Ber. 10, 

 542 ; 1 276 ; Claesson and Berg, Ber. 13, 

 1170; Fahlberg, Ber. 12, 1052; Sen- 

 hofer, Ann. 164, 126 ; Klason, Ber. 19, 

 2890), and fusion with potash (Hakan- 

 son, Loc. cit. 1087; Noelting, Ber. 19, 



^\ 



Or from o-toluidine through 4-nitro- 



2-toluidine by nitration (Noelting and 

 Collin, loc. cit. 265), 4-nitro-2-cresol by 

 the diazo-method (nitroindazole is 

 simultaneously formed : Noelting and 

 Collin, loc. cit. 269 ; Witt, Noelting, 

 and Grandmougin, Ber. 23, 3636 ; 

 Michel and Grandmougin, Ber. 26, 

 2351), 4-amino-2-eresol by reduction 

 (Noelting and Collin, Ber. 17, 270), 

 and the diazo-reaction with the latter 

 (Wallach, Ber. 15, 2835). 



The two nitrotoluidines required for 



