- 3-Methyl-2(1H)-pyrazinones, the Asparagine-Specific Maillard Products Formed from Asparagine and Monosaccharides
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Four unknown compounds from the reactions of monosaccharides and asparagine have been positively identified by spectroscopic elucidation and synthesis as 3,5-dimethyl-6-ethyl-2(1H)-pyrazinone, 3,6-dimethyl-5-ethyl-2(1H)-pyrazinone, 3,5,6-trimethyl-2(1H)-pyrazinone, and 3-methyl-5,6-diethyl-2(1H)-pyrazinone, which are novel to model reaction studies.This group of compounds can be recognized as asparagine-specific Maillard products.The formation mechanism of them has been proposed.Basically, 3-aminosuccinimide, asparagine, and isoasparagine may be at an equilibriumstate.Condensation of isoasparagine and α-dicarbonyls (the degradation products of the monosaccharide) leads to the formation of 3-(carboxymethyl)-5,6-dialkyl-2(1H)-pyrazinones, decarboxylation of which generates 3-methyl-5,6-dialkyl-2(1H)-pyrazinones.Identification of this group of compounds from Maillard reaction was herein reported for the first time in literature.Keywords: Asparagine; fructose; glucose; rhamnose; alkylpyrazines; Maillard reaction; 3,6-dimethyl-5-ethyl-2(1H)-pyrazinone; 3,5-dimethyl-6-ethyl-2(1H)-pyrazinone; 3,5,6-trimethyl-2(1H)-pyrazinone; 3-methyl-5,6-diethyl-2(1H)-pyrazinone; 3,6-dimethyl-5-propyl-2(1H)-pyrazinone; 3,5-dimethyl-6-propyl-2(1H)-pyrazinone
- Shu, Chi-Kuen,Lawrence, Brian M.
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- Studies on the mechanism of 1,2-dihydropyrazin-2-one ring formation from dipeptidyl chloromethyl ketone and its chemical properties: Immediate deamination during catalytic hydrogenation
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1,2-Dihydropyrazin-2-one derivatives, which have two aminoalkyl groups at the positions 3 and 6, were found to be efficient tools for the construction of potent, selective and long-acting opioid mimetics. During the course of preparation, we found that the catalytic hydrogenation of 3,6- bis(benzyloxycarbonylaminomethyl)-5-methyl-1,2-dihydropyrazin-2-one to remove the benzyloxycarbonyl groups resulted in a side reaction. By MS and NMR studies and by preparation of additional 1,2-dihydropyrazin-2-one derivatives, the structure of the by-product was identified as 3-aminomethyl-5,6-dimethyl-1,2- dihydropyrazin-2-one. Preparation of additional compounds substituted with deuterium provided us with sufficient information to confirm the structure of the product and to support a cyclization mechanism in its formation.
- Miyazaki, Anna,Fujisawa, Yutaka,Shiotani, Kimitaka,Fujita, Yoshio,Li, Tingyou,Tsuda, Yuko,Yokoi, Toshio,Bryant, Sharon D.,Lazarus, Lawrence H.,Okada, Yoshio
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p. 1152 - 1158
(2007/10/03)
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- Immediate deamination from the aminomethyl group attached to 1,2-dihydropyrazin-2-one derivative during catalytic hydrogenation
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The catalytic hydrogenation of 3,6-bis(benzyloxycarbonylaminomethyl)-5-methyl-1,2-dihydropyrazin-2-one to remove benzyloxycarbonyl (Z) groups resulted in a side reaction. Purification by reverse-phase HPLC and analysis by proton nuclear magnetic resonance
- Okada, Yoshio,Fujisawa, Yutaka,Morishita, Akihisa,Shiotani, Kimitaka,Miyazaki, Anna,Fujita, Yoshio,Li, Tingyou,Tsuda, Yuko,Yokoi, Toshio,Bryant, Sharon D.,Lazarus, Lawrence H.
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p. 8137 - 8139
(2007/10/03)
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- PYRAZINES, PYRIMIDINES AND PYRIDAZINES USEFUL IN THE TREATMENT OF SENILE DEMENTIA
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The present invention provides pyrazines, pyridazines or pyrimidines, or salts or prodrugs thereof, substituted on one of the ring carbon atoms thereof with a non-aromatic azacyclic or azabicyclic ring system; and independently substituted on each of the other ring carbon atoms with a substituent of low lipophilicity or a hydrocarbon substituent; which compounds stimulate central muscarinic acetylcholine receptors and therefore are useful in the treatment of neurological and mental illnesses.
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