2283-43-4

Upstream product

• 951-55-3 5-methyl-DL-tryptophan 
• 1148-11-4 N-Benzyloxycarbonyl-L-proline 
• 74761-41-4 (S)-1-(methoxycarbonyl)pyrrolidine-2-carboxylic acid 
• 147-85-3 L-proline 
• 93272-07-2 5-methyl-N_b-methoxycarbonyl-L-tryptophan methyl ester 
• 83541-81-5 (S)-dimethyl pyrrolidine-1,2-dicarboxylate 
• 93299-41-3 5-methyl-L-tryptophan methyl ester 
• 93272-14-1 5-methyl-N_b-benzyloxycarbonyl-L-tryptophan 
• 93299-30-0 N-methoxycarbonyl-L-glutamine methyl ester 
• 93271-96-6 (2S,5RS)-1,2-dimethyl-5-hydroxypyrrolidine-1,2-dicarboxylate 
• 93271-98-8 N-methoxycarbonyl-4-cyano-L-2-aminobutyric acid methyl ester 
• 93272-12-9 5-methyl-N_b-benzyloxycarbonyl-L-tryptophan methyl ester 
• 93271-97-7 1-benzyl 2-methyl (2S)-5-hydroxypyrrolidine-1,2-dicarboxylate 
• 5211-23-4 N-carbobenzyloxy-L-proline methyl ester 

Relevant academic research and scientific papers

Substituent Effects on the Spectral, Acid-Base, and Redox Properties of Indolyl Radicals: A Pulse Radiolysis Study

Spectral and acid-base properties and reduction potentials of various substituted indolyl radicals were studied by pulse radiolysis in aqueous solutions at 20 deg C.Except for the 5-methoxyindolyl and 5-carboxyindolyl radicals, the spectra of the substituted indolyl radicals resemble the previously published 320- and 520-nm spectra of the neutral and 330- and 580-nm spectra of the cation indolyl and tryptophan radicals.The substitution of indolyl radical cation by electron-attracting groups (positive ?+) results in a blue shift of the 580-nm band by ca. 30 nm,, whereas the spectra of methylindolyl (?+ = -0.31) are similar to those of unsubstituted indolyl radicals.The 430- and 455-nm bands appearing in the spectra of the 5-carboxyindolyl and 5-methoxyindolyl radical cations, respectively, indicate even stronger interaction of the unpaired electron with the 5-substituent.The radical cations of various indole-3-acetic acids decarboxylate at pH values below their pKa to produce allyl radicals.The 5-bromoindolyl radical undergoes solvolysis to 5-hydroxyindolyl radical in acidic and alkaline media.The dissociation constants and reduction potentials of the substituted indolyl radicals correlate with the Brown substituent constants: pKr = 4.14 - 2.13Σ?+, correlation coefficient 0.987, and E0/0.059 = 22.29 + 3.5Σ?+, correlation coefficient 0.980.The ρ values from these correlations (-2.13 and 3.5) are similar to that of the Hammett correlation of the dissociation constants of the protonated indole nitrogen in various substituted indoles, ρ = -2.49, but smaller than the ρ value of the dependence on the substituent of the reduction potentials of phenoxyl radicals, ρ = 5.4.

Syntheses of Substituted L- and D-Tryptophans

Several 5-substituted nb-methoxycarbonyl-L- and -D-tryptophan derivatives were synthesized from proline by a new route involving electrochemical oxidation, as well as by the known procedures.Removal of the Nb-methoxycarbonyl group was accomplished by treatment with Me3SiI in refluxing chloroform, then alkaline hydrolysis of the methyl esters afforded 5-substituted L- and D-tryptophans with high optical purities.Keywords - L-tryptophan 5-substituted; D-tryptophan 5-substituted; anodic oxidation; N-methoxycarbonyl group deprotection; Fischer indole synthesis; iodotrimethylsilane