15707-23-0Relevant articles and documents
Efficient synthesis method of 2-ethyl-3-methylpyrazine
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Paragraph 0024; 0029; 0035; 0041; 0049; 0053, (2018/04/01)
The invention discloses an efficient synthesis method of 2-ethyl-3-methylpyrazine. The method comprises specific steps as follows: 2,3-pentanedione is prepared from lactic acid as a raw material, a porous carrier is prepared from raw materials including diammonium hydrogen phosphate and barium nitrate, caesium supported on the carrier is taken as a catalyst, and the conversion rate of lactic acidis effectively increased; then, prepared 2,3-pentanedione and ethylenediamine are taken as raw materials and are sequentially subjected to dehydration condensation and dehydrogenation reactions, and 2-ethyl-3-methylpyrazine is prepared. The synthesis method is simple, low in cost and high in product yield.
Influence of Free Amino Acids, Oligopeptides, and Polypeptides on the Formation of Pyrazines in Maillard Model Systems
Scalone, Gustavo Luis Leonardo,Cucu, Tatiana,De Kimpe, Norbert,De Meulenaer, Bruno
, p. 5364 - 5372 (2015/06/25)
Pyrazines are specific Maillard reaction compounds known to contribute to the unique aroma of many products. Most studies concerning the generation of pyrazines in the Maillard reaction have focused on amino acids, while little information is available on the impact of peptides and proteins. The present study investigated the generation of pyrazines in model systems containing whey protein, hydrolyzed whey protein, amino acids, and glucose. The impact of thermal conditions, ratio of reagents, and water activity (aw) on pyrazine formation was measured by headspace solid-phase microextraction with gas chromatography/mass spectrometry (HS-SPME-GC/MS. The presence of oligopeptides from hydrolyzed whey protein contributed significantly to an increased amount of pyrazines, while in contrast free amino acids generated during protein hydrolysis contributed to a lesser extent. The generation of pyrazines was enhanced at low aw (0.33) and high temperatures (>120 °C). This study showed that the role of peptides in the generation of pyrazines in Maillard reaction systems has been dramatically underestimated.
The effect of pH on the formation of aroma compounds produced by heating a model system containing l-ascorbic acid with l-threonine/l-serine
Yu, Ai-Nong,Zhang, Ai-Dong
experimental part, p. 214 - 219 (2011/12/14)
The identification of aroma compounds, formed from the reactions of l-ascorbic acid with l-threonine/l-serine at five different pH values (5.00, 6.00, 7.00, 8.00, or 9.55) and 143 ± 2 °C for 2 h, was performed using a SPME-GC-MS technique, and further use
Pt/Al2O3 CATALYSTS IN THE SYNTHESIS OF NITROGEN HETEROCYCLES. CATALYTIC SYNTHESIS OF PYRAZINES
Gitis, K. M.,Neumoeva, G. E.,Isagulyants, G. V.
, p. 1308 - 1315 (2007/10/02)
A study was carried out on the use of Pt/Al2O3 catalysts in the synthesis of pyrazines via the dehydrogenation of piperazines, dehydrodeamination of diamines, and dehydrocyclocondensation of N-hydroxyalkyldiamines.In contrast to the current hypothesis of the intermediate formation of piperazine in the latter two reactions, evidence was found that these reactions proceed through initial dehydrogenation and the dehydrogenated intermediate then undergoes cyclization.Polyalkylpyrazines, formed by the alkylation of the pyrazine ring by hydrogenolysis products, are the major side-products in all the reactions studied.Pyrazines may be obtained in high yield and satisfactory selectivity by selecting suitable modifiers, which enhance the dehydrogenation activity of the catalyst and suppress the hydrogenolysis of the C-N bond.
Ueber die Synthese von 2,3-Dialkylpyrazinen
Heyns, Kurt,Behse, Ernst,Francke, Wittko
, p. 240 - 245 (2007/10/02)
2,3-Dialkylquinoxalines (4), which are available from the reaction of benzofuroxan (1) with ketones and subsequent reduction of the 2,3-dialkylquinoxaline N,N'-dioxides (3), are converted to 2,3-dialkylpyrazines (6) by oxidation-decarboxylation steps.
