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Upstream product

• 4790-04-9 5-benzyloxy-6-methoxy-indole 
• 74-88-4 methyl iodide 

Relevant academic research and scientific papers

Solvochromic effects in model eumelanin compounds

We have created an indolic compound which is ideally suited to the study of the relationship between structure and function in eumelanin formation. N-methyl-5-hydroxy-6-methoxyindole (MHMI) is stable in solid and liquid states, highly soluble in a variety of solvents and forms a dimer only through the 4-4′ positions. The limited binding possibilities are due to functional groups strategically placed to inhibit chemical interactions through the 2 and 7 positions. It forms a crystal structure with a remarkable packing arrangement, with four monomers grouped in parallel pairs spaced 3.5 A apart within each unit cell. Optical spectra reveal a multi-peaked absorbance profile similar to 5,6-dihydroxyindole (DHI) and N-acetyl-tryptophanamide (NATA), and strong fluorescence emission with radiative quantum yields of 29% and 33% in benzene and acetonitrile, respectively. The quantum yield is similar to that of 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and shows that solvent aromaticity by itself does not affect the yield. Solution in chloroform results in an almost complete quenching of the fluorescence but an increase in emission is observed with photoactivation. Crystallographic results shown here suggest new structural possibilities for eumelanin and the controlled binding possibilities make this an excellent model for monitoring changes in function with increasing oligomer size in eumelanin formation.

Effect of dimerization on vibrational spectra of eumelanin precursors

We have synthesized a compound ideally suited to the study of structure-function relationships in eumelanin synthesis. N-methyl-5-hydroxy-6- methoxy-indole (MHMI) has key functional groups strategically placed on the indole framework to hinder binding in the 2, 5, 6 and 7 positions. Thus, the dimer bound exclusively in the 4-4′ positions was isolated and characterized. In order to study the difference in vibrational structure between the MHMI monomer and dimer, Raman spectra were acquired of both compounds, as well as indole, indole-2-carboxylic acid and 5,6-dihydroxyindole-2-carboxylic acid (DHICA). Peaks were assigned to particular vibrational modes using B3LYP density functional theory calculations, and experimental and theoretical spectra displayed good agreement. Addition of functional groups to either benzene or pyrrole rings in the indole framework impacted vibrational spectra attributed to vibrations in either ring, and in some cases, peaks appearing unchanged between two compounds corresponded to different contributing vibrations. Dimerization resulted in an expected increase in the number of vibrational modes, but not a significant increase in the number of apparent peaks, as several modes frequently contributed to an individual observed peak. Comparison of spectral features of the monomer and dimer provides insight into eumelanin photochemistry, but final conclusions depend on the planarity of oligomeric structure in vivo.