27331-98-2Relevant academic research and scientific papers
Corrole-Substituted Fluorescent Heme Proteins
Lemon, Christopher M.,Marletta, Michael A.
supporting information, p. 2716 - 2729 (2021/02/16)
Although fluorescent proteins have been utilized for a variety of biological applications, they have several optical limitations, namely weak red and near-infrared emission and exceptionally broad (>200 nm) emission profiles. The photophysical properties of fluorescent proteins can be enhanced through the incorporation of novel cofactors with the desired properties into a stable protein scaffold. To this end, a fluorescent phosphorus corrole that is structurally similar to the native heme cofactor is incorporated into two exceptionally stable heme proteins: H-NOX from Caldanaerobacter subterraneus and heme acquisition system protein A (HasA) from Pseudomonas aeruginosa. These yellow-orange emitting protein conjugates are examined by steady-state and time-resolved optical spectroscopy. The HasA conjugate exhibits enhanced fluorescence, whereas emission from the H-NOX conjugate is quenched relative to the free corrole. Despite the low fluorescence quantum yields, these corrole-substituted proteins exhibit more intense fluorescence in a narrower spectral profile than traditional fluorescent proteins that emit in the same spectral window. This study demonstrates that fluorescent corrole complexes are readily incorporated into heme proteins and provides an inroad for the development of novel fluorescent proteins.
An expedient synthesis of cyanoformates via DAST-mediated C–C bond cleavage of α-oximino-β-ketoesters
Kim, Danhee,Lim, Hee Nam
supporting information, (2021/05/10)
A new protocol to synthesize cyanoformates was developed using simple β-ketoesters as substrates. (Diethylamino)sulfur trifluoride (DAST) was used as a dual-role reagent to activate the oxime moiety and to donate a fluoride. The key intermediates, α-oximino-β-ketoesters, were prepared by highly efficient acid-assisted oximation of β-ketoesters. Then, the deconstruction of α-oximino-β-ketoesters by the fluorinative C–C bond cleavage was demonstrated to provide cyanoformates. In this event, the fluoride addition followed by the C–C bond cleavage selectively occurred in the ketones over esters. Due to simple and mild reaction conditions, variously functionalized cyanoformates were exemplified.
Size-Selective Hydroformylation by a Rhodium Catalyst Confined in a Supramolecular Cage
Nurttila, Sandra S.,Brenner, Wolfgang,Mosquera, Jesús,van Vliet, Kaj M.,Nitschke, Jonathan R.,Reek, Joost N. H.
supporting information, p. 609 - 620 (2019/01/04)
Size-selective hydroformylation of terminal alkenes was attained upon embedding a rhodium bisphosphine complex in a supramolecular metal–organic cage that was formed by subcomponent self-assembly. The catalyst was bound in the cage by a ligand-template approach, in which pyridyl–zinc(II) porphyrin interactions led to high association constants (>105 m?1) for the binding of the ligands and the corresponding rhodium complex. DFT calculations confirm that the second coordination sphere forces the encapsulated active species to adopt the ee coordination geometry (i.e., both phosphine ligands in equatorial positions), in line with in situ high-pressure IR studies of the host–guest complex. The window aperture of the cage decreases slightly upon binding the catalyst. As a result, the diffusion of larger substrates into the cage is slower compared to that of smaller substrates. Consequently, the encapsulated rhodium catalyst displays substrate selectivity, converting smaller substrates faster to the corresponding aldehydes. This selectivity bears a resemblance to an effect observed in nature, where enzymes are able to discriminate between substrates based on shape and size by embedding the active site deep inside the hydrophobic pocket of a bulky protein structure.
Nitrite ionic liquids (IL-ONO and [bmim]NO2) as effective nitrosonium sources for the synthesis of α-oximinoketones under mild heterogeneous conditions
Valizadeh,Shomali,Gholipour
experimental part, p. 163 - 166 (2012/03/10)
Ketones and β-diketones were nitrosated and converted to their corresponding α-oximinoketones using task-specific ionic liquids, 1-(4-nitritobutyl)-3-methylimidazolium chloride, IL-ONO, and 1-butyl-3-methylimidazolium nitrite at room temperature. The results from two ionic liquids are comparable and showed that these IL's are effective nitrosonium sources for the preparation of oximinoketones. The protocol is rapid, the yields are excellent, and the method is simple. Copyright
COMPOSITIONS AND METHODS FOR TREATMENT OF NEURODEGENERATIVE DISEASE
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Page/Page column 33, (2011/10/13)
Compounds, compositions, kits and methods for treating conditions related to neurodegeneration or ocular disease, are disclosed.
Normal and abnormal heme biosynthesis. Part 7. Synthesis and metabolism of coproporphyrinogen-III analogues with acetate or butyrate side chains on rings C and D. Development of a modified model for the active site of coproporphyrinogen oxidase
Lash, Timothy D.,Lamm, Teresa R.,Schaber, J. Andy,Chung, Wen-Hsiang,Johnson, Eric K.,Jones, Marjorie A.
experimental part, p. 1492 - 1504 (2011/04/12)
Analogues of coproporphyrinogen-III have been prepared with acetate or butyrate groups attached to the C and D pyrrolic subunits. The corresponding porphyrin methyl esters were synthesized by first generating a,c-biladienes by reacting a dipyrrylmethane with pyrrole aldehydes in the presence of HBr. Cyclization with copper(II) chloride in DMF, followed by demetalation with 15% H2SO4-TFA and reesterification, gave the required porphyrins in excellent yields. Hydrolysis with 25% hydrochloric acid and reduction with sodium-amalgam gave novel diacetate and dibutyrate porphyrinogens 9. Diacetate 9a was incubated with chicken red cell hemolysates (CRH), but gave complex results due to the combined action of two of the enzymes present in these preparations. Separation of uroporphyrinogen decarboxylase (URO-D) from coproporphyrinogen oxidase (CPO) allowed the effects of both enzymes on the diacetate substrate to be assessed. Porphyrinogen 9a proved to be a relatively poor substrate for CPO compared to the natural substrate coproporphyrinogen-III, and only the A ring propionate moiety was processed to a significant extent. Similar results were obtained for incubations of 9a with purified human recombinant CPO. Diacetate 9a was also a substrate for URO-D and a porphyrinogen monoacetate was the major product in this case; however, some conversion of a second acetate unit was also evident. The dibutyrate porphyrinogen 9b was only recognized by the enzyme CPO, but proved to be a modest substrate for incubations with CRH. However, 9b was an excellent substrate for purified human recombinant CPO. The major product for these incubations was a monovinylporphyrinogen, but some divinyl product was also generated in incubations using purified recombinant human CPO. The incubation products were converted into the corresponding porphyrin methyl esters, and these were characterized by proton NMR spectroscopy and mass spectrometry. The results extend our understanding of substrate recognition and catalysis for this intriguing enzyme and have allowed us to extend the active site model for CPO. In addition, the competitive action of both URO-D and CPO on the same diacetate porphyrinogen substrate provides additional perspectives on the potential existence of abnormal pathways for heme biosynthesis.
Synthetic porphyrins bearing β-propionate chains as photosensitizers for photodynamic therapy
Pereira, Nelson,Serra, Arménio C.,Pineiro, Marta,Gonsalves, António M. D'A. Rocha,Abrantes, Margarida,Laranjo, Mafalda,Botelho, Filomena
scheme or table, p. 438 - 445 (2010/12/18)
Porphyrins with different numbers of β-propionate chains mimicking natural porphyrins were prepared via the 2+2 MacDonald type approach. Photodynamic activity against WiDr colon adenocarcinoma cells showed that activity is related to the number of β-propi
Solution versus fluorous versus solid-phase synthesis of 2,5-disubstituted 1,3-azoles. Preliminary antibacterial activity studies
Sanz-Cervera, Juan F.,Blasco, Rauel,Piera, Julio,Cynamon, Michael,Ibanez, Ignacio,Murguia, Marcelo,Fustero, Santos
supporting information; experimental part, p. 8988 - 8996 (2010/03/24)
(Chemical Equation Presented) A small library of compounds with an oxa(thia)zole scaffold and structural diversity in both positions 2 and 5 has been synthesized. Double acylation of a protected glycine affords intermediate α-amido-β-ketoesters, which in turn can be dehydrated to afford 1,3-oxazoles or reacted with Lawesson's reagent to furnish 1,3-thiazoles. This procedure was designed with its adaptation to fluorous techniques in mind. Thus, when a protected glycine with a fluorous tag in the ester moiety is used as a starting material, the synthesis can be easily completed without column chromatography purification of intermediate compounds with good to excellent yields, thus affording a suitable entry to the preparation of small libraries of these bioactive compounds. The prepared oxa(thia)zoles were assayed for their antibacterial activity, and several of them were active against Staphylococcus aureus.
Electron transfer in bis-porphyrin donor-acceptor compounds with polyphenylene spacers shows a weak distance dependence
Helms, Anna,Heiler, David,McLendon, George
, p. 6227 - 6238 (2007/10/02)
A series of phenylene-bridged bis-porphyrin adducts have been synthesized, containing one, two, or three phenyl bridges. Complete synthetic details are provided. For studies of photochemical electron transfer, mixed metals wre incorporated, with zinc in one porphyrin macrocycle and FeIII (bis-imidazole) in the other macrocycle. When photoexcited, an electron is transferred from Zn to FeIII. The rate of this process drops only slowly with distance: kα exp(βr), with β = 0.4 A?-1. This dependence can be predicted by a simple theory which assumes that the drop does not reflect increased distance, but rather reflects the break in conjugation which occurs at each phenyl juncture due to the biphenyl twist angle of ca. 50°. Inefficient overlap in this angle results in a rate drop of ca. 6-fold per phenyl ring, in good agreement with the observed results.
Vibrational and electronic spectra of new liposoluble metalloporphyrins in a nonpolar noncoordinating solvent
Ringuet, Michel,Girard, Denis,Chapados, Camille
, p. 1070 - 1079 (2007/10/02)
A new liposoluble porphyrin, 2,7,12,17-tetrahexyl-3,8,13,18-tetramethylporphin (THTMP), and its complexes with divalent (Mg, Co, Ni, Cu, Zn, Cd, Hg) and trivalent (Mn, Fe) metals have been synthesized.The electronic, infrared, and far-infrared spectra of
