How to translate text using browser tools
1 April 2002 The Light-induced Reactions of Tryptophan with Halocompounds
Robert A. Edwards, Glen Jickling, Raymond J. Turner
Author Affiliations +

The light-dependent reaction between N-acetyl-l-tryptophanamide (NATA) and chloroform has been examined using fluorescence, NMR and reverse phase chromatography. The emission of NATA in the presence of CHCl3 decreases at 360 nm and increases at longer wavelengths (∼480 nm) upon illumination with 280 nm light. The action spectrum for the formation of the 480 nm emitting product(s) has the same shape as the excitation spectra of the indole fluorophore in NATA. The pH of the solution decreases as the reaction proceeds. The reaction rate depends on the intensity of the illumination and is of the first order with respect to both [NATA] and [CHCl3]. NMR and reverse phase chromatography results demonstrate that multiple products are formed. The reaction products give new peaks between 8.9 and 10.5 ppm in the 1H-NMR that are assigned to –CHO groups, which are added to the indole ring. Some of the products react with 2,4-dinitrophenylhydrazine and thus confirm this assignment. A scheme is proposed in which the excited indole gives off a solvated electron to initiate a series of steps that yield indole derivatives in which a –CHO group has replaced a –H in the indole ring. Similar reactions are observed when 5-hydroxytryptophan, 5-fluorotryptophan or N-methylindolacetate is used instead of tryptophan or when the chloroform is replaced with other trichlorinated compounds, such as trichloroacetic acid, trichloroethanol and trichloroethane, as well as the tribrominated compound, bromoform, and the monoiodinated compound, iodoactetate.

Robert A. Edwards, Glen Jickling, and Raymond J. Turner "The Light-induced Reactions of Tryptophan with Halocompounds," Photochemistry and Photobiology 75(4), 362-368, (1 April 2002).<0362:TLIROT>2.0.CO;2
Received: 2 August 2001; Accepted: 1 January 2002; Published: 1 April 2002

This article is only available to subscribers.
It is not available for individual sale.

Get copyright permission
Back to Top