- 著者
- 狐塚 寛 小山 又次郎 興津 知明
- 出版者
- The Pharmaceutical Society of Japan
- 雑誌
- Chemical and Pharmaceutical Bulletin (ISSN:00092363)
- 巻号頁・発行日
- vol.30, no.3, pp.941-945, 1982-03-25 (Released:2008-03-31)
- 参考文献数
- 9
- 被引用文献数
- 5 6
The murexide reaction of caffeine was investigated to clarify the pathway of the coloration. From the reaction mixture of caffeine with nitric acid, 1, 3-dimethylalloxan (II) and 1, 3, 7-trimethyl-2, 6-dioxo-8-nitro-1H, 3H, 7H-xanthine (IV) were isolated. Compound II was found to be the key intermediate, since it was converted to a purple-red-colored substance, murexoin (III), by treatment with conc. ammonia. It was found that 1-hydroxy-5, 7-dimethyl-2, 4, 6-trioxo-1H, 5H, 7H-oxazolo [4, 5-d] pyrimidine (I), previously obtained by the oxidation of caffeine with hydrogen peroxide and hydrochloric acid, was also transformed to III with conc. ammonia. Consequently, the murexide reaction of caffeine was shown to have two pathways of coloration depending on the oxidizing agent employed. From the spectral data, a symmetrical structure (III) was assigned to murexoin in solution. Amalic acid, which has been reported as an intermediate of the murexide reaction of caffeine, can be ruled out on the basis of our experimental results.
1 0 0 0 Murexide反応の呈色機構に関する研究
- 著者
- 狐塚 寛 小山 又次郎 興津 知明
- 出版者
- 公益社団法人日本薬学会
- 雑誌
- CHEMICAL & PHARMACEUTICAL BULLETIN (ISSN:00092363)
- 巻号頁・発行日
- vol.29, no.2, pp.433-437, 1981
- 被引用文献数
- 7
The murexide reaction was investigated to clarify the mechanism of the coloration, with caffeine as a model compound. From the reaction mixture of caffeine with hydrogen peroxide and hydrochloric acid, 1-hydroxy-5, 7-dimethyl-2, 4, 6-trioxo-1H, 5H, 7H-oxazolo-[4, 5-d] pyrimidine (yellow oil) (I) and 1, 3, 7-trimethyl-2, 6, 8-trioxo-9-hydroxy-1H, 3H, 7H-xanthine (red powder) (II) were isolated, and these two compounds were shown to be responsible for the murexide reaction of caffeine. Compound I was regarded as a key intermediate, since its purple coloration with dil. ammonia was similar to that of caffeine developed by the murexide reaction. The absorption maximum of II corresponds to that of the red-colored solution obtained from the reaction of caffeine with hydrogen peroxide and hydrochloric acid.
- 著者
- 狐塚 寛 小山 又次郎 興津 知明
- 出版者
- The Pharmaceutical Society of Japan
- 雑誌
- Chemical and Pharmaceutical Bulletin (ISSN:00092363)
- 巻号頁・発行日
- vol.29, no.2, pp.433-437, 1981-02-25 (Released:2008-03-31)
- 参考文献数
- 6
- 被引用文献数
- 4 7
The murexide reaction was investigated to clarify the mechanism of the coloration, with caffeine as a model compound. From the reaction mixture of caffeine with hydrogen peroxide and hydrochloric acid, 1-hydroxy-5, 7-dimethyl-2, 4, 6-trioxo-1H, 5H, 7H-oxazolo-[4, 5-d] pyrimidine (yellow oil) (I) and 1, 3, 7-trimethyl-2, 6, 8-trioxo-9-hydroxy-1H, 3H, 7H-xanthine (red powder) (II) were isolated, and these two compounds were shown to be responsible for the murexide reaction of caffeine. Compound I was regarded as a key intermediate, since its purple coloration with dil. ammonia was similar to that of caffeine developed by the murexide reaction. The absorption maximum of II corresponds to that of the red-colored solution obtained from the reaction of caffeine with hydrogen peroxide and hydrochloric acid.