In a preliminary note on the subject one of the authors and K.Mayeda (this Journ. No.477, Nov.1921) described an acidic compound C
15H
16O
5 or (C
6H
5·C
7H
7O
2) (OCH
3)·COOH. which was obtained by treating kawa resin with aqueous caustic potash at ordinary temperature. Borsche and Roth (Ber. 54, 2229) obtained a compound named kawaic acid (C
13H
12O
3) from kawa resin by heating it with aqueous caustic soda, wich on distillation in vacuo lost CO
2 and yielded cinnamalaceton. hThey considered the constitution of their kawaic acid to be C
6H
5CH : CH·CH : C (CH
3) CO·COOH or C
6H
3·CH : CH·CH : CH·CO·CH
3·COOH, but an attempt to synthesize it gave no deffinite result. When kawaic acid of M. and S. (C
15H
16O
3) was treated with aqueous caustic potash at 100° a compound C
14H
16O
3 or rather C
14H
14O
3 (m.p. 175-177°) was obtained, which yielded cinnamalaceton on warming with dilute sulphuric acid. The latter was also obtained directly from kawaic acid by treating with dilute sulphuric acid or on distillation under diminished pressure. Probably the kawaic acid of Borsche (m p. 164-165°) may be identical with the alkali decomposition product of the kawaic acid of M. and S., as the latter at first melts at about 165°, which by repeated recrystallisation attains the constant m.p. 177-179°. The authors demonstrated the chemical constitution and transformation of the kawaic acid as follows : [numerical formula] The further confirmation of this formula is at present in pragress. Kawaic Acid. To prepare this acid 100g of the kawa resin was shaken with 300 c.c. of 6% aqueous caustic potash for 5-7 hours. The separated crystalline substances were fiitrated off and the filtrate was acidified with 5% acetic acid fractionately. At first a yellowish crystalline substance (m.p. 177-179°) and then the crude kawaic acid are presipitated. The latter, dissolved in chloroform, was shaken several times with sodium carbonate solution, which was acidified with acetic acid. The kawaic acid, after recrystallisation from absolute ether melted at 87°. The yield was 0.5% of the root. [table] The optical rotation was [α]
20D-40
00 in 10% alcoholic solution. Alkali Decomposition of Kawaic acid. 10g of kawaic acid was mixed with 100cc. of 10% sodium hydroxide solution and warmed on the water bath for 7 hours. The reaction mixture was acidified with dilute acetic acid, when resinous decomposition products were separated. On repeated recrystallization from acetone, a yellowish bright krystalline substance m.p. 175-177° (formerly 164°) was obtained. It is in soluble in cold sodium carbonate solution, soluble in hot carbonate solution and on cooling a krystalline sodium compounds separated out, from which the original substance may be isolated by the acid. Hnalysis : -[table] Methoxyl number (Zeisl's method) [talbe] The alkali decomposition product m.p. 175-177° was warmed with dilute sulphuric acid. The reaction mixture was distilled with steam, when yellow krystals passed over which were collected and dried on porous plate. It melted at 67-68° after recrystallization from absolute ether. [table] Action of dilute Sulphuric acid on Kawaic acid. 10g of kawaic acid was mixed with 400cc. of 5% sulphuric acid and warmed on the water bath for 2-3 hours. The reaction mixture was distilled with steam, the oily distillate was converted into semicarbazone in the usual manner. [the rest omitted]
抄録全体を表示