136 D-138 A.] 



EUXANTHONE 



233 



verted into 5~ ammosa li c yh c acid (see 

 under quinol [71; D]), which gives 

 gentisic acid as above under B. 



Benzoic acid can also be converted 

 into gentisic acid through o-nitro- and 

 anthranilic acid, o-uraminobenzoic acid, 

 dinitrouraminobenzoic acid, 5-nitro- 

 2-aminobenzoic acid, 5-nitro- and 5- 

 aminosalicylic acid, and then as above 

 under B. Or through 3-brombenzoic 

 acid, the 3-brom-6-nitro- and correspond- 

 ing amino-acid, 5-bromsalicylic acid, 

 and then as above under B [71; D]. 



[E.] From resorcinol [70] and an- 

 thranilic ( = i-aminobenzoic) acid [Vol. 

 II]. The latter can be converted into 

 gentisic acid as above under D. 



[F.] From resorcinol [70] and gentisin 

 [137]. The latter gives gentisic acid 

 on fusion with potash [71 ; L].- 



[G.] From resorcinol [70], furfural 

 [126], and acetone [106]. The two 

 latter can be made to furnish p-nitro- 

 phenol (as under resorcinol [70; H]), 

 from which gentisic acid can be ob- 

 tained as above under C. 



[H.] From quinol [7l] and umbelli- 

 ferone [Vol. II], the latter yielding /3- 

 resorcylic acid on fusion with potash 

 (see under resorcinol [70; E]). 



NOTES : /3-Resorcylic acid can bo obtained 

 also from toluene directly [70 ; B]. Euxanthic 

 acid has been synthesised by the action of 

 acetbromglycuronic acid on the sodium deriva- 

 tive of euxanthone (Neuberg and Niemann, 

 Centr. med. Wiss. 40, 529; Ch. Centr. 1902, 

 2, 844). For constitution of euxanthone see 

 Kostanecki, Ber. 27, 1989. 



137. Gentisin ; 

 Methylgentisein ; Gentianin ; 

 : 7-Hydroxy-3-Methoxyxanthone. 



CO 



HO 



OCH 3 



II 



O 



NATURAL SOURCE. 



In the root of Gentiana lutea from 

 Switzerland and the Tyrol (Tromms- 

 dorff, Ann. 21, 134; Leconte, Ann. 25, 

 202 ; Baumert, Ann. 62, 106 ; A. G. 

 Perkin, Trans. Ch. Soc. 73, 672). 



SYNTHETICAL PROCESSES. 



[A.] From quinol [7l] through gen- 

 tisic acid (see under euxanthone [136 ; 

 A]), pkloroghicinol [86], and methyl 

 alcohol (methyl iodide) [13]. Phloro- 

 glucinol and gentisic acid, when heated 

 with acetic anhydride, give gentise'in, 

 and this yields gentisin on methyla- 

 tion (Kostanecki and Tambor, Monats. 

 15, 4). 



The quinol may be replaced by the 

 other generators of gentisic acid referred 

 to under exanthone [136 ; B ; C ; D ; 

 E ; F; G], viz. salicylic acid [Vol. II], 

 phenol [60], benzoic or anthranilic acid 

 [Vol. II], furfural [126], and acetone 

 [106]. 



138. Clirysin ; 

 1 : 3-Dihyclroxyflavoiie. 



C.C,H 5 

 CH 



HO 



NATURAL SOURCE. 



In the buds of various species of 

 poplar, such as Populns nigra, P. bal- 

 samifera, P. pyramidalis, &c. (Piccard, 

 Ber. 6, 884; 7, 888; 10, 176). 



SYNTHETICAL PROCESSES. 



[A.] ~Fromj}Moroglucinol [86], benzoic 

 and acetic acids [Vol. II], methyl [13], 

 and ethyl alcohol [14]. Phloroglucinol 

 is converted into its trimethyl ether 

 (see under methylhydrocotom [135 ; 

 A]), and the latter condensed with 

 acetyl chloride (by means of aluminium 

 chloride) so as to give phloroaceto- 

 phenone trimethyl ether (Friedlander 

 and Schnell, Ber. 30, 2152). The 

 latter condenses with ethyl benzoate 

 in presence of sodium ethoxide with the 

 formation of 2 : 4 : 6-trimethoxybenzoyl- 

 acetophenone, (CH 3 O) 3 . C 6 H 2 . CO . 

 CH 2 . CO . C G H 5 . The latter on heating 

 with strong aqueous hydriodic acid gives 

 chrysin (Emilewicz, Kostanecki, and 

 Tambor, Ber. 32, 2448). 



