- PETROPORPHYRINS-III. CHARACTERISATION OF A C32 AETIOPORPHYRIN FROM GILSONITE AS THE BISMERCURY(II) COMPLEX. ORIGIN AND SIGNIFICANCE
-
A C32 aetio porphyrin isolated from Gilsonite bitumen (ca. 60 million yr) was assigned unambiguously as aetioporphyrin-III by 1H NMR analysis of its bismercury(II) complex and by comparison with an authentic sample.The occurrence of this compound provides the first direct evidence that the petroporphyrins of Gilsonite are the product of reductive degradation of naturally-occurring chlorophylls, and conversion of the chlorin to the porphyrin system.
- Quirke, J. Martin E.,Maxwell, James R.
-
-
Read Online
- Comprehensive determination of chlorophyll derivatives by chromic acid oxidation
-
It is difficult to measure the total amount of chlorophyll derivatives due to their variety. We applied a new method for comprehensive determination of all derivatives by ethylmethylmaleimide (EMMi) derived from chlorin which is a ring structure of chloropigments. Relationships between the amount of applied chloropigments and the yield of EMMi through the chromic acid oxidation were examined for three species of chloropigments. The yield of EMMi from chloropigments was almost constant regardless of the amount or pigment species, indicating the applicability of this method for comprehensive deterimination of chlorophyll derivatives.
- Satoh, Yuhi,Nomoto, Shinya,Hama, Takeo
-
-
Read Online
- 2-Ethyl-3-methylmaleimide in Tokyo Bay sediments providing the first evidence for its formation from chlorophylls in the present photic and oxygenic zone
-
Tokyo Bay bottom sediments were analyzed for 2-ethyl-3-methylmaleimide, a degradation product of chlorophylls, which has been detected in ancient sediments. It was found in all sediments examined in concentrations of about 1 to 15 nmol/g- of dried sediment, and it was shown to be preserved for 100 years in the sediments. Its depth distribution agreed with that of the reported total organic carbon content of the sediments, reflecting a change in primary productivity. We concluded that this maleimide was produced under photic and oxygenic conditions in nature before the incorporation of photosynthesizing organisms into sediments.
- Kozono, Masaki,Nomoto, Shinya,Mita, Hajime,Ishiwatari, Ryoshi,Shimoyama, Akira
-
-
Read Online
- Preparation method of 2-methyl-3-ethyl maleic amide
-
The invention relates to a preparation method of 2-methyl-3-ethyl maleic amide. The method comprises the following steps: preparing dimethyl maleic anhydride; preparing 2-methyl-3-ethyl maleic anhydride; and preparing 2-methyl-3-ethyl maleic amide. A process route develops a synthetic method of a series of maleimide and maleic anhydride, and meanwhile, a flavoring application experiment is performed on the series of precursor-aroma compounds, thereby providing an important support for developing novel perfume materials.
- -
-
Page/Page column 0080-0081; 0092-093; 0104-105; 0116-0117; 0128
(2017/08/29)
-
- The first experimental demonstration of side chain extension of geoporphyrins in sediments
-
To investigate the formation process of high carbon number (>C 32) sedimentary porphyrins, heating experiments of several porphyrins were performed. Chromic acid oxidation of the heating products of protoporphyrin IX dimethyl ester afforded 2-methyl-3-npropylmaleimide as the predominant product among the side-chain extension products formed. On the other hand, saturated substituents of etioporphyrin were also extended on heating to slowly form normal and branched homologs. These results may suggest that the transalkylation of porphyrin side chains proceeds mainly by a regioselective mechanism involving alkyl radical addition to a vinyl group of chlorophylls or their diagenetic products.
- Asahina, Kenta,Asano, Junya,Kumagai, Gen,Satou, Mitsuru,Nomoto, Kouichi,Kashiyama, Yuichiro,Mita, Hajime,Nomoto, Shinya
-
body text
p. 1267 - 1269
(2011/02/16)
-
- A new maturity indicator of sedimentary organic matter based on thermal fission of allylic bond in porphyrins
-
A 3-ethyl-4-methylpyrrole unit in etioporphyrin was shown to be converted to a 3,4-dimethylpyrrole unit by the action of heat, which was proved to be catalyzed by Na-montmorillonite. Time courses of the reaction could be followed by analyzing 2-ethyl-3-me
- Nomoto, Shinya,Kozono, Masaki,Mita, Hajime,Shimoyama, Akira
-
p. 1174 - 1175
(2007/10/03)
-
- Reactivity of Pyrrole Pigments, Part 15: On the Oxidation of Bilirubins and Biliverdins
-
Characteristic oxidation reactions of bilin-1,19-diones (biliverdins) and biladien-ac-1,19-diones (bilirubins) were reinvestigated.These include bromine and iodine oxidation of biliverdin IXα, bilirubin IXα and their Zn(II)complexes, the reaction described by Siedel (1941) of mesobilirubin XIIIα dimethyl ester with nitric acid (Gmelin reaction) and Smith's oxidation (1977) of etiobiliverdin IVγ using Tl triacetate and Pb tetra-acetate.For some of these reaction products new structures were assigned on the basis of their spectrometric data.These structures agreed with the expected reactivity pattern of biliverdins and bilirubins. Keywords: Bilipurpurins; Biliviolins; Electron transfer vs.Electrophilic attack.
- Acero, C.,Ribo, J. M.,Sole, R.,Trull, F. R.
-
p. 401 - 418
(2007/10/02)
-
- Synthesis and Characterization of Monothiosuccinimides
-
The synthesis and characterization are described of a series of monothiosuccinimides.These imides are potentially valuable synthetic intermediates, particularly for the preparation of a bile pigments.Also described are the synthesis and unusual chemical and spectral behavior of a monothiomaleimide derivative, whose X-ray crystallographic structure was determined.
- Bishop, John E.,Dagam, Shekhar A.,Rapoport, Henry
-
p. 1876 - 1883
(2007/10/02)
-
- Relative Stereochemistry of the A Ring of Plant Bile Pigments
-
The synthesis and characterization, including the stereochemistry, of a series of 3,4-dihydropyrromethenones and 2,3-dihydrodioxobilins are described.High-resolutions 1H NMR spectral analysis allows the determination of the A ring coupling constants for a series of cis and trans model compounds.From these data and correlations, the relative stereochemistry in the A ring of phycocyanin and similar bile pigment structures can be concluded.
- Schoenleber, Robert W.,Kim, Youseung,Rapoport, Henry
-
p. 2645 - 2651
(2007/10/02)
-
- Structurel Analysis of Tetrapyrroles by Hydrogen Chemical Ionization Mass Spectrometry
-
The H2 chemical ionization mass spectra of several standard porphyrins have been determined.Fragmentation proceeds via hydrogenation yielding porphyrinogens, followed by cleavage at the meso (bridge) positions to produce mono-, di-, and tripyrrolic ions.Secondary fragmentation by cleavage of substituent groups attached to the pyrrole rings may then occur.Identification of these fragments and the corresponding molecular ions produces considerable structural information on the parent molecule.In certain cases these data are sufficient to distinguish porphyrin type (positional) isomers.In addition information of substituents at meso positions may be retained.
- Shaw, George J.,Eglinton, Geoffrey,Quirke, J. Martin E.
-
p. 2014 - 2020
(2007/10/02)
-
- PETROPORPHYRINS - II. THE PRESENCE OF PORPHYRINS WITH EXTENDED ALKYL SUBSTITUENTS
-
The vanadyl porphyrins from Boscan oil (Cretaceous, W.Venezuela) were isolated as 3 fractions, and degraded to maleimides (1H-pyrrole-2,5-diones) by chromic acid.Analysis of the products by GC-MS, using multiple ion detection to enhance sensitivity, revealed a major homologous series of 3-Me components with n-alkyl side chains extending to C11, and a minor series with branched alkyl side chains, the Me branch being at C-1.The origin of the extended alkyl groups is discussed.
- Martin, J.,Quirke, E.,Shaw, George J.,Soper, Paul D.,Maxwell, James R.
-
p. 3261 - 3268
(2007/10/02)
-
