Catechol, 4,5-diamino

C5H8N2, Pyrazole, 3,5-dimethyl-, complexes with tungsten, 33 219 C6H8N2O2, Catechol, 4,5-diamino-, 33 112 C6HgBrN202, Benzene, l,2-dihydroxy-4,5-diamino-, hydrobromide, 33 115 C8H12N2O2, Benzene, l,2-dimethoxy-4,5-diamino-, 33 115... 

N2O2C6H8, Catechol, 4,5-diamino-, 33 112 N2O2C8H12, Benzene, l,2-dimethoxy-4,5-diamino-, 33 115... 

Alterobactin, a 19-membered macrocydic depsipeptide containing two types of unusual building block, two i-threo- -hydroxyaspartic acids and one (3S,4S)-4,8-diamino-3-hydroxyoctanic acid attached to a catechol carboxylate at the N -site. It was isolated from a open-ocean bacterium M-teromonas luteoviolacea coUected off Chub Cay, Bahamas. Alterobadin is a depsipeptide siderophore exhibiting extraordinary affinity for ferric ion. The total synthesis has been described [R. T. Reid et al.. Nature 1993, 366, 455 J. Deng et al.. Synthesis 1998, 627]. 

Two new ligands N,N-bis(3,5-dimethylpyrazol-l-ylmethyl)benzylamine, bpmba, and N,N,N, N tetrakis(3,5-dimethylpyrazol-l-ylmethyl)-a,a -diamino-/n-xylene. bpmdx have recently been synthesized [26] their copper complexes are active catalysts for the oxidation of catechol to 0 benzoquinone. 

Electrochemical oxidation of catechol in the presence of carbohydrazide in aqueous solution using carbon electrode resulted in benzimidazole derivatives by cyclic voltammetry and controlled-potential coulometry techniques [20] (Scheme 49). A direct electron transfer mechanism occurred during the process on the surface of carbon. The investigators proposed that the Michael adduct formed between the carbohydrazide and o-quinone (Eqn (2)) leads to the formation of l,3-diamino-5,6-dihydroxy-lH-benzo[d]imidazole-2(3H)-one 52. 

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