32736-94-0Relevant academic research and scientific papers
Pheromone synthesis. Part 261: Synthesis of four pyrazines produced by females of the Korean apricot wasp, Eurytoma maslovskii
Mori, Kenji,Yang, Chang Yeol
, p. 4766 - 4769 (2017)
Four pyrazines were synthesized as sex specific volatiles of female Korean apricot wasp, Eurytoma maslovskii. They are 2,5-dimethyl-3-vinylpyrazine (1), 2,5-dimethyl-3-(2-methylpropyl)pyrazine (2), 2,5-dimethyl-3-(2-methylbutyl)pyrazine (3), and 2,5-dimethyl-3-(3-methylbutylpyrazine (4). They were synthesized in 74–85% yields by Pd- or Fe-catalyzed cross-coupling reactions between 3-chloro-2,5-dimethylpyrazine and CH2=CHBF3K or RMgBr. The present synthesis of 1 is the most reliable and scalable one to date.
Impact of the N-terminal amino acid on the formation of pyrazines from peptides in maillard model systems
Van Lancker, Fien,Adams, An,De Kimpe, Norbert
scheme or table, p. 4697 - 4708 (2012/08/27)
Only a minor part of Maillard reaction studies in the literature focused on the reaction between carbohydrates and peptides. Therefore, in continuation of a previous study in which the influence of the peptide C-terminal amino acid was investigated, this study focused on the influence of the peptide N-terminal amino acid on the production of pyrazines in model reactions of glucose, methylglyoxal, or glyoxal. Nine different dipeptides and three tripeptides were selected. It was shown that the structure of the N-terminal amino acid is determinative for the overall pyrazine production. Especially, the production of 2,5(6)-dimethylpyrazine and trimethylpyrazine was low in the case of proline, valine, or leucine at the N-terminus, whereas it was very high for glycine, alanine, or serine. In contrast to the alkyl-substituted pyrazines, unsubstituted pyrazine was always produced more in the case of experiments with free amino acids. It is clear that different mechanisms must be responsible for this observation. This study clearly illustrates the capability of peptides to produce flavor compounds such as pyrazines.
Novel pyrazines from the myxobacterium Chondromyces crocatus and marine bacteria
Dickschat, Jeroen S.,Reichenbach, Hans,Wagner-Doebler, Irene,Schulz, Stefan
, p. 4141 - 4153 (2007/10/03)
The volatiles released by two strains of the myxobacterium Chondromyces crocatus and seven strains of marine Alpha-proteobacteria from the North Sea were collected using the CLSA or SPME headspace methods and analysed by GC-MS. In the extracts of C. crocatus 27 pyrazines were identified, belonging to different classes. 2,5-Dialkylpyrazines and related 3-methoxy-2,5- dialkylpyrazines dominated. Several pyrazines like 2-(1-methylethenyl)-5-(1- methylethyl)-pyrazine (7) and 3-methoxy-2,5-dialkylpyrazines with methyl, isopropyl, isobutyl or sec-butyl side-chains were obtained from natural sources for the first time. It was essential for the identification to rely on synthetic reference materials, which were obtained using Fuerstner's iron-catalysed coupling of chloropyrazines with Grignard reagents or condensation of azido ketones as key steps. The synthetic material allowed the identification of two previously unknown attractants of bacterial origin for the pineapple beetle Carpophilus humeralis, namely 3-methoxy-2-(1-methylpropyl)-5-(2-methylpropyl) pyrazine (17) and 3-methoxy-2,5-bis(1-methylpropyl)pyrazine (52). Several 2,5-dialkylpyrazines were identified in the extracts of the marine Alphaproteobacteria. The unique 2,5-dimethyl-3-(methylsulfanyl)pyrazine (67) represents a new type of natural pyrazine. Our results, together with literature reports, show that pyrazines are an important class of bacterial volatiles which might be more widespread than previously thought. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.
