Reaktionen von o-Chinonen mit Aminen und Proteinen. 4. Mitteilung. 7a-Methyl-5,6-dioxo-5,6,7,7a-tetrahydroindol-Derivate aus 4-Methylbrenzcatechin und Enaminen
✍ Scribed by Martin G. Peter; Fritz Speckenbach
- Publisher
- John Wiley and Sons
- Year
- 1982
- Tongue
- German
- Weight
- 336 KB
- Volume
- 65
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Reactions of o‐Quinones with Amines and Proteins. 7a‐Methyl‐5,6,7,7a‐tetrahysroindole Derivatives from 4‐Methylcatechol and Enamines
Methyl l‐[2′‐(methoxycarbonyl)ethyl]‐7a‐methyl‐5,6‐dioxo‐5.6.7,7a‐tetrahydro‐indole‐3‐carboxylate (1) was isolated after the oxidation of 4‐methylcatechol with silver (1) oxide in the presence of b̃‐alanine methyl ester in glacial acetic acid. The formation of 1 requires in situ dehydrogenation of the b̃‐aminocarboxylate and addition of the resulting enamine to 4‐methyl‐1,2‐benzoquinone. Reaction of ethyl 3‐(phenylamino)crotonate with 4‐methyl‐1,2‐benzoquinone afforded ethyl 2,7a‐dimethyl‐5,6‐dioxo‐1‐phenyl‐5,6,7,7a‐tetrahydroindole‐3‐carboxylate (6). Despite the fact that the yields are low, the addition of enamines to o‐quinones represents an interesting novel extension of the Nenitzescu‐reaction which is well known in the p‐quinone series. Compound 1 may be considered as a novel model for the crosslinking of proteins by o‐quinones. Formation of 1 was, however, not observed under physiological conditions.