42205-74-3Relevant articles and documents
Tuning the stereoelectronic factors of iron(ii)-2-aminophenolate complexes for the reaction with dioxygen: oxygenolytic C-C bond cleavagevs. oxidation of complex
Chatterjee, Sayanti,Banerjee, Sridhar,Jana, Rahul Dev,Bhattacharya, Shrabanti,Chakraborty, Biswarup,Jannuzzi, Sergio Augusto Venturinelli
, p. 1901 - 1912 (2021)
Oxidative C-C bond cleavage of 2-aminophenols mediated by transition metals and dioxygen is a topic of great interest. While the oxygenolytic C-C bond cleavage reaction relies on the inherent redox non-innocent property of 2-aminophenols, the metal complexes of 2-aminophenolates often undergo 1e?/2e?oxidation events (metal or ligand oxidation), instead of the direct addition of O2for subsequent C-C bond cleavage. In this work, we report the isolation, characterization and dioxygen reactivity of a series of ternary iron(ii)-2-aminophenolate complexes [(TpPh,Me)FeII(X)], where X = 2-amino-4-tert-butylphenolate (4-tBu-HAP) (1); X = 2-amino-4,6-di-tert-butylphenolate (4,6-di-tBu-HAP) (2); X = 2-amino-4-nitrophenolate (4-NO2-HAP)(3); and X = 2-anilino-4,6-di-tert-butylphenolate (NH-Ph-4,6-di-tBu-HAP) (4) supported by a facial tridentate nitrogen donor ligand (TpPh,Me= hydrotris(3-phenyl-5-methylpyrazol-1-yl)borate). Another facial N3ligand (TpPh2= hydrotris(3,5-diphenyl-pyrazol-1-yl)borate) has been used to isolate an iron(ii)-2-anilino-4,6-di-tert-butylphenolate complex (5) for comparison. Both [(TpPh,Me)FeII(4-tBu-HAP)] (1) and [(TpPh,Me)FeII(4,6-di-tBu-HAP)] (2) undergo regioselective oxidative aromatic ring fission reaction of the coordinated 2-aminophenols to the corresponding 2-picolinic acids in the reaction with dioxygen. In contrast, complex [(TpPh,Me)FeII(4-NO2-HAP)] (3) displays metal based oxidation to form an iron(iii)-2-amidophenolate complex. Complexes [(TpPh,Me)FeII(NH-Ph-4,6-di-tBu-HAP)] (4) and [(TpPh2)FeII(NH-Ph-4,6-di-tBu-HAP)] (5) react with dioxygen to undergo 2e?oxidation with the formation of the corresponding iron(iii)-2-iminobenzosemiquinonato radical species implicating the importance of the -NH2group in directing the C-C bond cleavage reactivity of 2-aminophenols. The systematic study presented in this work unravels the effect of the electronic and structural properties of the redox non-innocent 2-aminophenolate ring and the supporting ligand on the C-C bond cleavage reactivityvs. the metal/ligand oxidation of the complexes. The study further reveals that proper modulation of the stereoelectronic factors enables us to design a well synchronised proton transfer (PT) and dioxygen binding events for complexes1and2that mimic the structure and function of the nonheme enzyme 2-aminophenol-1,6-dioxygenase (APD).
Synthesis, Crystal Structure and Catalytic Activities of
Ko, Po-Hung,Chen, Tai-Yuen,Zhu, Jin,Cheng, Kin-Fai,Peng, Shie-Ming,Che, Chi-Ming
, p. 2215 - 2220 (2007/10/03)
The compound H2bbpc , which has good solubility in organic solvents, has been prepared.Reaction of with H2bbpc in ethanol and in the presence of triethylamine gave , the crystal structure of which has been determined.This complex is an active catalyst for alkene epoxidation by PhIO, cyclopropanation of styrene by ethyl diazoacetate and aziridination of styrene by PhINO2SC6H4Me-p.Its cyclic voltammogram in dichloromethane showed a reversible Ru(III)-Ru(II) couple at -0.55 V and an oxidation couple at 0.32 V.
Synthesis and antimicrobial actvity of clindamycin analogues: Pirlimycin, a potent antibacterial agent
Birkenmeyer,Kroll,Lewis,et al.
, p. 216 - 223 (2007/10/02)
The preparation of a series of analogues of clindamycin is described in which the naturally occurring five-membered cyclic amino acid amide portion of the molecule is replaced by a four-, six-, or seven-membered cyclic amino acid amide. The most interesting compounds is pirlimycin (U-57,930E), in which the (2S-trans)-4n-propylhygramide portion of clindamycin is replaced by (2S-cis)-4-ethylpipecolamide. This structural modification results in significantly favorable changes in toxicity, metabolism, and antibacterial potency. Although the in vitro antibacterial activity of clindamycin and pirlimycin are nearly identical, the latter compounds is 2-20 times more active than clindamycin when administered to mice experimentally infected with strains of Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, Bacteroides fragilis, and Plasmodium berghei. Pirlimycin is absorbed in rats and mice and is sequestered within these abscesses. A drug concentration of at least 60 times the required inhibitory concentration is maintained for 6 h following a single subcutaneous dose of 200 mg/kg. Urinary excretion of total bioactivity consists only of intact pirlimycin with no other antibacterially active metabolites being detected. Pirlimycin is tolerated well in rats and mice at the administered levels.
