- From N-(dinitrophenyl) amino acids to benzimidazole N-oxides. Synthesis, kinetics and mechanism
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Several benzimidazole N-oxide derivatives were synthesized in very good yields by heating under reflux the corresponding N-(2,4- or 2,6-dinitrophenyl) amino acid derivative with NaOH in 60% 1,4-dioxane-H2O. The N-oxides obtained from glycine and α- and β-alanine derivatives lost the carboxylic group. The observed rate constant for the reaction of N-(2,4-dinitrophenyl) glycine (2a) in 10% 1,4-dioxane-H2O to give 5-nitro-1H-benzimidazole-3-oxide (4a) is first order on [NaOH]; the second-order rate constant is kN=1.7 × 10-3 M-1 S-1. The mechanism proposed includes the formation of an N-alkylidene 2-nitrosoaniline-type intermediate as the rate-determining step. Copyright
- Bujan, Elba I.,Salum, Maria Laura
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- Method for photolysis of amido bonds
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The invention discloses a method for photo-splitting amido bonds, wherein the method is mild in reaction condition and can realize splitting of amido bonds by using illumination. The method for photo-splitting the amido bonds comprises the following steps: reacting 2,4-dinitrofluorobenzene with an amino group of a substance which contains alpha amino acid at the tail end and is shown as a structural formula I to generate a compound 1 represented by a structural formula II; and under light irradiation, carrying out amido bond cleavage reaction on the compound 1, wherein R1 is a side chain group of alpha-amino acid, and R2 is aryl, aliphatic hydrocarbon, -CH(R)-COOH or polypeptide.
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Paragraph 0046; 0048-0049
(2021/06/26)
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