4758-64-9Relevant academic research and scientific papers
Normal and abnormal heme biosynthesis. 1. Synthesis and metabolism of di- and monocarboxylic porphyrinogens related to coproporphyrinogen-III and harderoporphyrinogen: A model for the active site of coproporphyrinogen oxidase
Lash, Timothy D.,Mani, Ukti N.,Drinan, Martin A.,Zhen, Chun,Hall, Troii,Jones, Marjorie A.
, p. 464 - 477 (2007/10/03)
Coproporphyrinogen oxidase (copro'gen oxidase), which catalyses the conversion of coproporphyrinogen-III via a monovinylic intermediate to protoporphyrinogen-IX, is one of the least well understood enzymes in the heme biosynthetic pathway. To develop a model for the substrate recognition and binding recognition for this enzyme, a series of substrate analogues were prepared with two alkyl substituents on positions 13 and 17 in place of the usual propionate residues. Although the required substrate probes are porphyrinogens (hexahydroporphyrins), the corresponding porphyrin methyl esters were initially synthesized via a,c-biladiene intermediates. These were hydrolyzed and reduced with 3% sodium amalgam to give the unstable porphyrinogens needed for the biochemical investigations. These modified structures were metabolized by avian preparations of copro'gen oxidase to give monovinylic products, but the second propionate residue was not further metabolized. In three cases, the metabolites were isolated and further characterized by proton NMR spectroscopy and mass spectrometry. When methyl or ethyl groups were placed at the 13 and 17 positions, the resulting porphyrinogens were very good substrates (although the ethyl version, mesoporphyrinogen-VI, gave slightly better results), but when propyl units were introduced metabolism was significantly inhibited and the butyl- substituted structure was only slightly transformed after long incubation periods. These results suggest the presence of an active site lipophobic region near the catalytic site for copro'gen oxidase. The observation that the related 3-vinyl- and 3-ethylporphyrinogens with 13,17-diethyl substituents were not substrates for this enzyme confirmed the need for a second propionate residue to hold the substrate in place at the catalytic site.
Enantioselection in bilirubin analogs with only one propionic acid group
Boiadjiev, Stefan E.,Lightner, David A.
, p. 3603 - 3615 (2007/10/03)
Enantiopure synthetic bilirubin analogs (1 and 2) with only a single β- methyl propionic acid group adopt a folded, ridge-tile conformation stabilized by intramolecular hydrogen bonding. The β-methyl group forces the pigment to adopt a left-handed (M) helical conformation, as evidenced by exciton circular dichroism spectra and indicating that one propionic acid group is sufficient to control the pigment's conformation.
Regioselective pyrrole synthesis from asymmetric β-diketone and conversion to sterically hindered porphyrin
Fujii, Hiroshi,Yoshimura, Tetsuhiko,Kamada, Hitoshi
, p. 1427 - 1430 (2007/10/03)
The condensation of asymmetric β-diketones with α-oximinoacetoacetate esters affords pyrroles regioselectively. The mechanism of the regioselectivity is studied using 13C-NMR spectroscopy. Pyrrole having a neopentyl group at the 4-position is synthesized by the method, and further converted to a steric hindered porphyrin in good yield.
Boron difluoride compounds useful in photodynamic therapy and production of laser light
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, (2008/06/13)
A new group of fluorescent organic compounds having a variety of uses are described. They are especially useful as dye compounds in dye laser systems, and as photochemical agents in the treatment of diseased tissues using photodynamic therapy techniques. The compounds include a tri-cyclic compound having the following structure: STR1 Preferably R1 -R5 =R9 -R12 =C; R7 =B; R6 and R8 =N; R14 =lower n-alkyl or an electron withdrawing group such as CN- ; R16 and R19 are independently selected from the group consisting of lower n-alkyl, a sulfate or an acid or salt thereof, or hydrogen; and R20 =R21 =F. Other compounds include compounds of the formula STR2
Thermochemistry of substituted pyrroles
Berezin, M. V.,Semeikin, A. S.,V'yugin, A. I.,Krestov, G. A.
, p. 449 - 453 (2007/10/02)
The heats of solution of a series of substituted pyrroles in benzene, carbon tetrachloride, chloroform, DMF, and pyridine were measured by a calorimetric method at 298.15 K.The influence of substituents in the pyrrole molecule on the energy parameters of solvation by organic solvents is discussed.
Pyrrole Chemistry. An Improved Synthesis of Ethyl Pyrrole-2-carboxylate Esters from Diethyl Aminomalonate
Paine, John B.,Dolphin, David
, p. 5598 - 5604 (2007/10/02)
Ethyl pyrrole-2-carboxylates, versatile precursors for the total synthesis of both synthetic model and naturally occurring tetrapyrroles and porphyrins, can be prepared in greatly improved yields by the addition of 1,3-diketones and preformed diethyl aminomalonate to boiling glacial acetic acid.The method is suitable for both small- and large-scale synthesis and has proved far more reliable than the original in situ dissolving zinc reduction of diethyl oximinomalonate discovered by Kleinspehn.Yields range from 60-70percent for the dominant product isomer from unsymmetrical diketones to 75-90percent for the single product derived from symmetrical diketones.Seventeen examples of alkyl-substituted ethyl pyrrole-2-carboxylates are provided.Improved procedures are given for the preparation of the required precursors.
Alkylation process
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, (2008/06/13)
Substituted pyrrole compounds, such as 3-ethyl-4-methyl-5-carbethoxy pyrrole, 2,4-dimethyl-3-acetyl pyrrole and 2-methyl-5-carboxy pyrrole-4-propionic acid diethyl ester, are alkylated in a single step by reaction with an aldehyde or ketone in the presence of both an acid condensing agent such as hydriodic acid and a compatible reducing agent such as metallic zinc or stannous chloride. Suitable carbonyl reactants include formaldehyde, paraldehyde, isobutyraldehyde, acetone, cyclohexanone and methyl-isobutyl ketone. This application is a continuation application of U.S. application Ser. No. 281,624 filed Aug. 18, 1972, now abandoned, which is a continuation-in-part application of U.S. application Ser. No. 832,001, filed June 10, 1969, now abandoned.
