619-45-4Relevant articles and documents
Photosensitive self-assembled monolayers on gold: Photochemistry of surface-confined aryl azide and cyclopentadienylmanganese tricarbonyl
Wollman, Eric W.,Kang, Doris,Frisbie, C. Daniel,Lorkovic, Ivan M.,Wrighton, Mark S.
, p. 4395 - 4404 (1994)
Photosensitive self-assembled monolayers (SAMs) are prepared by the spontaneous reaction of di-11-(4-azidobenzoate)-1-undecyl disulfide, I, or 11-mercaptoundecylcyclopentadienylmanganese tricarbonyl, II, with polycrystalline Au. SAMs of I are photosensitive by virtue of a pendant aryl azide moiety (λmax = 270 nm, log ε = 4.2) which undergoes photoreaction with secondary amines to form Au-confined derivatives of 3-H azepine and hydrazine, while Au-II SAMs undergo photosubstitution of phosphine for CO. Au-I SAMs irradiated in the presence of various secondary amines were characterized by reflection absorption infrared spectroscopy (RAIRS), XPS, and cyclic voltammetry, and showed persistent attachment of approximately one monolayer of amine. Infrared spectroscopy was used to establish that primary photoproducts obtained upon irradiation of Au-I SAMs in diethylamine are nearly identical to primary photoproducts obtained upon irradiating an analog of I, methyl 4-azidobenzoate, in diethylamine solution. XPS analysis of Au-I SAMs before and after irradiation in the presence of secondary amines confirms loss of N2 from the Au-I SAM and incorporation of one nitrogen atom per surface-confined molecule. Most definitively, cyclic voltammetry of Au-I after irradiation in the presence of 2-ferrocenylethyl-2′,2′,2′-trifluoroethylamine, III, showed 3.3 × 10-10 mol cm-2 of surface-confined ferrocene. Positive ion SIMS spectra of Au-II irradiated in the presence of PPh2Et, PPh2(n-Pr), PPh2(CH2)11Fc, X, Fc = ferrocenyl, or PPh2(CH2)2(CF2)5CF 3, XI, show that introduction of the phosphine onto the surface occurs upon near-UV irradiation. Importantly, the surface photochemistry of I and II allows the high lateral resolution patterning of Au surfaces and Au microstructures with a variety of molecular reagents. SIMS maps for vinyl ferrocenium (m/z 212) or F- (m/z 19) of flat Au-II substrates irradiated through a Cr-on-glass mask in the presence of X or XI demonstrate photochemical patterning at a lateral resolution of 2H5OH)2NH.
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Schwartz,Paruta
, p. 252,253-255 (1976)
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Carboxyl Methyltransferase Catalysed Formation of Mono- and Dimethyl Esters under Aqueous Conditions: Application in Cascade Biocatalysis
Ashbrook, Chloe,Carnell, Andrew J.,Goulding, Ellie,Hatton, Harry,Johnson, James R.,Kershaw, Neil M.,McCue, Hannah V.,Rigden, Daniel J.,Ward, Lucy C.
supporting information, (2022/02/21)
Carboxyl methyltransferase (CMT) enzymes catalyse the biomethylation of carboxylic acids under aqueous conditions and have potential for use in synthetic enzyme cascades. Herein we report that the enzyme FtpM from Aspergillus fumigatus can methylate a broad range of aromatic mono- and dicarboxylic acids in good to excellent conversions. The enzyme shows high regioselectivity on its natural substrate fumaryl-l-tyrosine, trans, trans-muconic acid and a number of the dicarboxylic acids tested. Dicarboxylic acids are generally better substrates than monocarboxylic acids, although some substituents are able to compensate for the absence of a second acid group. For dicarboxylic acids, the second methylation shows strong pH dependency with an optimum at pH 5.5–6. Potential for application in industrial biotechnology was demonstrated in a cascade for the production of a bioplastics precursor (FDME) from bioderived 5-hydroxymethylfurfural (HMF).
Selective Reduction of Nitroarenes to Arylamines by the Cooperative Action of Methylhydrazine and a Tris(N-heterocyclic thioamidate) Cobalt(III) Complex
Ioannou, Dimitris I.,Gioftsidou, Dimitra K.,Tsina, Vasiliki E.,Kallitsakis, Michael G.,Hatzidimitriou, Antonios G.,Terzidis, Michael A.,Angaridis, Panagiotis A.,Lykakis, Ioannis N.
supporting information, p. 2895 - 2906 (2021/02/27)
We report an efficient catalytic protocol that chemoselectively reduces nitroarenes to arylamines, by using methylhydrazine as a reducing agent in combination with the easily synthesized and robust catalyst tris(N-heterocyclic thioamidate) Co(III) complex [Co(κS,N-tfmp2S)3], tfmp2S = 4-(trifluoromethyl)-pyrimidine-2-thiolate. A series of arylamines and heterocyclic amines were formed in excellent yields and chemoselectivity. High conversion yields of nitroarenes into the corresponding amines were observed by using polar protic solvents, such as MeOH and iPrOH. Among several hydrogen donors that were examined, methylhydrazine demonstrated the best performance. Preliminary mechanistic investigations, supported by UV-vis and NMR spectroscopy, cyclic voltammetry, and high-resolution mass spectrometry, suggest a cooperative action of methylhydrazine and [Co(κS,N-tfmp2S)3] via a coordination activation pathway that leads to the formation of a reduced cobalt species, responsible for the catalytic transformation. In general, the corresponding N-arylhydroxylamines were identified as the sole intermediates. Nevertheless, the corresponding nitrosoarenes can also be formed as intermediates, which, however, are rapidly transformed into the desired arylamines in the presence of methylhydrazine through a noncatalytic path. On the basis of the observed high chemoselectivity and yields, and the fast and clean reaction processes, the present catalytic system [Co(κS,N-tfmp2S)3]/MeNHNH2 shows promise for the efficient synthesis of aromatic amines that could find various industrial applications.
Optimizing the structure of (salicylideneamino)benzoic acids: Towards selective antifungal and anti-staphylococcal agents
Krátky, Martin,Kone?ná, Klára,Broke?ová, Kate?ina,Maixnerová, Jana,Trejtnar, Franti?ek,Vin?ová, Jarmila
, (2021/02/03)
An increasing resistance of human pathogenic bacteria and fungi has become a global health problem. Based on previous reports of 4-(salicylideneamino)benzoic acids, we designed, synthesised and evaluated their me-too analogues as potential antimicrobial agents. Forty imines derived from substituted salicylaldehydes and aminobenzoic acids, 4-aminobenzoic acid esters and 4-amino-N-phenylbenzamide were designed using molecular hybridization and prodrug strategies. The target compounds were synthesized with high yields and characterized by spectral methods. They were investigated against a panel of Gram-positive and Gram-negative bacteria, mycobacteria, yeasts and moulds. The most active imines were tested to determine their cytotoxicity and selectivity in HepG2 cells. Dihalogenosalicylaldehydes-based derivatives showed potent broad-spectrum antimicrobial properties, particularly against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (minimum inhibitory concentrations, MIC, from 7.81 μM) and Enterococcus faecalis (MIC of ≥15.62 μM), yeasts (MIC from 7.81 μM) and Trichophyton interdigitale mould (MIC of ≥3.90 μM). Methyl 4-[(2-hydroxy-3,5-diiodobenzylidene)amino]benzoate 4h exhibited excellent in vitro activity along with low toxicity to mammalian cells. This compound is selective for staphylococci, Candida spp. and Trichophyton interdigitale. In addition, this imine was evaluated as a potential inhibitor of Gram-positive biofilms. The successful approach used provided some promising derivatives with more advantageous properties than the parent 4-(salicylideneamino)benzoic acids.
