Indolyl carboxylic acids by condensation of indoles with alpha-keto acids.
The novel indole derivatives 2,2-bis(3,3'-indolyl)propionic acid (1); 1,1,1,-tris(3,3',3"-indolyl)ethane (2); and 2,2-bis(3, 3'-indolyl)isocaproic acid (3) were isolated from solvent extracts of indole-supplemented supernatants of Escherichia coli and corynebacteria. The compounds were also obtained by chemical synthesis: compounds 1 and 2 from indole and pyruvic acid and compound 3 from indole and alpha-ketoisocaproic acid, following incubation at 37 degrees C in aqueous medium. Tryptophan and pyruvic acid gave the novel 2-(2-tryptophanyl)lactic acid (4). The condensation reaction between indoles and alpha-keto acids was of general nature, and the mild reaction conditions suggested it may proceed in vivo. Examples for endogenous occurrence may be the neuro-degenerative diseases phenylketonuria and maple syrup urine disease, both characterized by elevated blood levels of alpha-keto acids.
Garbe
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TR
Mitsubishi Chemical Corporation, Tsukuba Research Center, 8-3-1, Chuo, Ami, Inashiki, Ibaraki, 300-0332 Japan. garbetr@rite.or.jp
Kobayashi
M
M
Shimizu
N
N
Takesue
N
N
Ozawa
M
M
Yukawa
H
H
D001951:Brevibacterium / Q000737:chemistry; D002264:Carboxylic Acids / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D004926:Escherichia coli / Q000737:chemistry; D005285:Fermentation; D007211:Indoles / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D012997:Solvents; D016339:Spectrometry, Mass, Fast Atom Bombardment
D002264:Carboxylic Acids; D007211:Indoles; D012997:Solvents