178-179 A.] 



APPENDIX 



[3] 19, 1010 : compare Gildemeister 

 and Hoffmann, op. cit. p. 818). A 

 menthene may occur in peppermint oil 

 (Andres and Andre'eff, Ber. 25, 609). 



SYNTHETICAL PROCESS. 



[A.] From menthol [4l] by heating 

 with sulphuric acid, pnosphorus pent- 

 oxide, zinc chloride, anhydrous cupric 

 sulphate, or acid potassium sulphate 

 (Walter, Ann. 32, 288; Beckmann, 

 Ann. 250, 358; Briihl, Ber. 25, 143; 

 Sicker and Kremers, Am. Ch. Journ. 

 14, 291 ; Urban and Kremers, Ibid. 16, 

 397 ; Helbing, Ibid. 18, 762 ; Richt- 



mann, Ibid. 763 ; Konowaloff, Journ. 

 Russ. Soc. 32, 76). 



Or menthol may be converted into 

 menthyl chloride by heating with phos- 

 phorus pentachloride, and the menthyl 

 chloride heated with aniline or quinoline 

 (Wagner, Ber. 27, 1636; Tolloczko, 

 Journ. Russ. Soc. 29, 48 ; Slawinski, 

 Ibid. 1 1 8 : see also Berkenheim, Ber. 

 25, 686 ; Kijner, Journ. Russ. Soc. 

 27, 473; Wallach, Ch. Centr. 1898, 

 1, 570 ; Masson and Reychler, Ber. 29, 

 1843; Tschugaeff, Ber. 32, 3332). 



NOTE : Menthene would precede cymene [0, 

 p. 28] in the scheme of chemical classification. 

 It is conveniently introduced here on account 

 of its genetic relationship to the terpenes. 



FLAVONE GROUP. 



179. Fisetiu; 

 3 ; 3 1 : ^-Trihydroxyflavonol. 



HO 



HO 



C OH 



>OH 



NATURAL SOURCES. 



The occurrence of fisetin in the wood 

 of Quebracho Colorado and of Rhus 

 cotinus is referred to under catechol 

 [69, p. 139]. Fisetin and a glucoside 

 thereof (not fustin) is also contained 

 in the stem of the yellow cedar, Rhus 

 rhodanthema, from N. S. Wales (A. G. 

 Perkin, Trans. Ch. Soc. 71, 1194). 



SYNTHETICAL PROCESS. 



[A.] From resorcinol [70], vanillin 

 [121], acetic acid [Vol. II], methyl and 

 ethyl, alcohols [13 ; 14]. Resorcinol and 

 acetic acid are converted into resaceto- 

 phenone (see under pseonol [133 ; A, 



p. 231], and the latter into its ethyl 

 ether by ethylation. Vanillin is methy- 

 lated so as to form the methyl ether 

 (veratric aldehyde), and the latter con- 

 densed with the resacetophenone ether 

 by the action of alkali in alcoholic 

 solution so as to form 2 1 -hydroxy-4 1 - 

 ethoxy-3 : 4-dimethoxychalkone : 



[i]CH.C 6 H 3 (OCH 3 ) 2 [ 3 : 4 ] 



(Kostanecki and Rozycki, Ber. 32, 

 2257). This unsaturated ketone on 

 boiling with an alcoholic solution of 

 dilute sulphuric acid is converted into 

 3 - ethoxy- 3 1 : 4 1 - dimethoxyflavanone, 

 which by interaction with amyl nitrite 

 forms isonitroso- 3- ethoxy -3 1 : 4 1 -di- 

 methoxyflavanone. The latter on heat- 

 ing with dilute sulphuric acid in acetic 

 acid solution gives 3-ethoxy~3 1 : 4 J -di- 

 methoxyflavonol, which on boiling with 

 strong hydriodic acid is completely 

 de-alkylated with the formation of 

 fisetin (Kostanecki, Lampe,and Tambor, 

 Ber. 37, 784). 



T 2 



