Maleimides in the Cretaceous/Tertiary boundary sediments at Kawaruppu, Hokkaido, Japan.

Abstract

Maleimides were detected in organic solvent extracts and chromic acid oxidation products of the Cretaceous/Tertiary boundary sediments at Kawaruppu. Free (organic solvent extractable) maleimides consisted of 2,3-dimethylmaleimide and 2-methyl-3-ethylmaleimide, and bound (oxidatively extractable) maleimides of 2-methylmaleimide and its 3-n-alkyl homologs up to C 4 , benzomaleimide (phthalimide) and its methyl homologs. The total concentrations of free and bound maleimides ranged from n.d. to 10 and from 4 to 49 nmol g -1 , respectively. The most abundant compound was 2-methyl-3-ethylmaleimide both in free and bound forms in all the sediments, indicating that the maleimides detected were very likely degradation products of porphyrins and/or chlorophylls. The concentrations of both forms of alkylmaleimides were significantly smaller in the boundary claystone than the sediments above and below it. Their depth profiles agreed with those of pristane plus phytane and n-alkanes, indicating smaller inputs of chlorophylls into the claystone, which relates to the large bio-mass extinction at the end of Cretaceous. The Kawaruppu sequence afforded the first case in which 2-methylmaleimide was the second most abundant maleimide, indicating a mild thermal history of the sediments. The ratios of 2,3-dimethyl-to 2-methyl-3-ethylmaleimide of both free and bound forms showed constant values above and below the boundary claystone, reflecting the uniform diagenesis experienced by the sediments. The ratios exhibited larger values within the claystone, which is possibly related to different precursor chlorophylls caused by the massive extinction of organisms.

Mono- and bicyclic alkanes and diamondoid hydrocarbons in the Cretaceous/Tertiary boundary sediments at Kawaruppu, Hokkaido, Japan.

“…Concentrations of all cyclic alkanes were found to relate to the large biomass extinction at the Cretaceous end. Among the cyclic alkanes, n-alkylcycloalkanes showed a Chen et al, 1996), e) ratios of β-to α-MN (methylnaphthalene), MP (methylphenanthlene) (Mita and Shimoyama, 1999b), and MDBT (methyldibenzothiophene) (Katsumata and Shimoyama, 2000), and f) 2, ) (Shimoyama et al, 2001) in the K/T boundary sediments at Kawaruppu. rather quick recovery of their biological sources. Other alkyl cyclohexanes, decalins, and diamondoid hydrocarbons showed no complete recovery to the abundance levels of the Cretaceous.…”

“…This time span might have been enough for some organisms to recover to the abundance level in the Cretaceous as revealed, for example, by n-alkanes, pristane and phytane (Mita and Shimoyama, 1999a) or not enough for others as shown by the C 25 highly branched isoprenoid thiophene (Katsumata and Shimoyama, 2000). Other studies of organic compounds in the Kawaruppu sediments are of amino acids (Mita et al, 1996) and dicarboxylic acids (Mita et al, 1998) for the search of extraterrestrial compounds, polycyclic aromatic hydrocarbons of combustion origin by wild fires (Mita and Shimoyama, 1999b), and maleimides possibly derived from chlorophyll (Shimoyama et al, 2001).…”

A new method for the rapid analysis of 1H-Pyrrole-2,5-diones (maleimides) in environmental samples by two-dimensional gas chromatography time-of-flight mass spectrometry

“…Maleimides have also been detected in environmental samples, where they have been used as indicators of algal productivity, water column properties (i.e. redox conditions, stratification, chemocline depth) and depositional conditions [19,20,[26][27][28][29][30][31][32][33][34][35]. However, the precursors of many maleimides have still not been fully identified, the processes leading to their formation are incompletely understood and their environmental significance needs further investigation [29].…”

2-Ethyl-3-methylmaleimide in Tokyo Bay Sediments Providing the First Evidence for its Formation from Chlorophylls in the Present Photic and Oxygenic Zone

“…In our previous study, Cretaceous W Tertiary sediments proved to contain no 2-methylmaleimide in spite of the existence of methylpyrrole-containing porphyrins in appreciable amounts. 8) This fact may rule out the possibility of diagenetic generation of maleimides from porphyrins in sediments. The maleimide detected in the ancient sediments could have been produced before the incorporation of dead bodies of photosynthesizing organisms into sediments, rather than from sedimentary porphyrins by the action of diagenesis in sediments.…”

“…2-Ethyl-3-methylmaleimide (1) was recently found in Permian and Triassic marine sediments by Grice et al, [5][6] and in Neogene and Cretaceous W Tertiary sediments by us, [7][8] together with other alkylmaleimides. The compound is a novel biomarker for chlorophylls, because many kinds of chlorophylls contain a 3-ethyl-4-methylpyrrole moiety.…”