- Reaction Scope of Methyl 1,2,3-Triazine-5-carboxylate with Amidines and the Impact of C4/C6 Substitution
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A comprehensive study of the reaction scope of methyl 1,2,3-triazine-5-carboxylate (3a) with alkyl and aryl amidines is disclosed, reacting at room temperature at remarkable rates (5 min, 0.1 M in CH3CN) nearly 10000-fold faster than that of unsubstituted 1,2,3-triazine and providing the product pyrimidines in high yields. C4 Methyl substitution of the 1,2,3-triazine (3b) had little effect on the rate of the reaction, whereas C4/C6 dimethyl substitution (3c) slowed the room-temperature reaction (24 h, 0.25 M) but displayed an unaltered scope, providing the product pyrimidines in similarly high yields. Measured second-order rate constants of the reaction of 3a-c, the corresponding nitriles 3e and 3f, and 1,2,3-triazine itself (3d) with benzamidine and substituted derivatives quantitated the remarkable reactivity of 3a and 3e, verified the inverse electron demand nature of the reaction (Hammett ρ = -1.50 for substituted amidines, ρ = +7.9 for 5-substituted 1,2,3-triazine), and provided a quantitative measure of the impact of 4-methyl and 4,6-dimethyl substitution on the reactivity of the methyl 1,2,3-triazine-5-carboxylate and 5-cyano-1,2,3-triazine core heterocycles.
- Qui?ones, Ryan E.,Wu, Zhi-Chen,Boger, Dale L.
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p. 13465 - 13474
(2021/09/28)
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- Probing the Scope of the Amidine–1,2,3-triazine Cycloaddition as a Prospective Click Ligation Method
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Despite recent achievements in the development of chemical reactions enabling selective modification of complex biomolecules, the demand for fast and efficient methodologies that allow the attachment of various functional groups to these systems is the subject of intense research. Here, we report on the study of the amidine–1,2,3-triazine cycloaddition reaction, which has the potential to address many of the challenges associated with the development of such chemistry. We describe an optimized protocol leading to the in situ formation of free amidine bases, which directly react in the cycloaddition reaction with 1,2,3-triazines. Our kinetic studies reveal the structural features determining the reaction rates. Finally, we show that the amidine–1,2,3-triazine cycloaddition is extraordinarily selective and orthogonal to other popular ligation reactions. The pros and cons of the methodology are presented.
- Siegl, Sebastian J.,Vrabel, Milan
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supporting information
p. 5081 - 5085
(2018/10/20)
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- P2X3 AND/OR P2X2/3 COMPOUNDS AND METHODS
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The present application provides novel compounds and methods for preparing and using these compounds. In one embodiment, the compounds are of the structure of formula (I), wherein R1-R4 are defined herein. In a further embodiment, these compounds are useful in method for regulating one or both of the P2X3 or P2X2/3 receptors. In another embodiment, these compounds are useful for treating pain in patients by administering one or more of the compounds to a patient.
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Paragraph 0182; 0185; 0186
(2015/07/07)
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- Inverse electron demand diels-alder reactions of 1,2,3-triazines: Pronounced substituent effects on reactivity and cycloaddition scope
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A systematic study of the inverse electron demand Diels-Alder reactions of 1,2,3-triazines is disclosed, including an examination of the impact of a C5 substituent. Such substituents were found to exhibit a remarkable impact on the cycloaddition reactivity of the 1,2,3-triazine without altering, and perhaps even enhancing, the intrinsic cycloaddition regioselectivity. The study revealed not only that the reactivity may be predictably modulated by a C5 substituent (R = CO2Me > Ph > H) but also that the impact is of a magnitude to convert 1,2,3-triazine (1) and its modest cycloaddition scope into a heterocyclic azadiene system with a reaction scope that portends extensive synthetic utility, expanding the range of participating dienophiles. Significantly, the studies define a now powerful additional heterocyclic azadiene, complementary to the isomeric 1,2,4-triazines and 1,3,5-triazines, capable of dependable participation in inverse electron demand Diels-Alder reactions, extending the number of complementary heterocyclic ring systems accessible with implementation of the methodology.
- Anderson, Erin D.,Boger, Dale L.
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p. 12285 - 12292
(2011/09/16)
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- PGD2 receptor antagonists for the treatment of inflammatory diseases
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Disclosed herein are compounds represented by Structural Formula (I) and (I-A): Also disclosed is the use of such compounds for inhibiting the G-protein coupled receptor referred to as chemoattractant receptor-homologous molecule expressed on Th2, or simp
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- A general procedure for the synthesis of 2-substituted pyrimidine-5-carboxylic esters
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A method for the synthesis of 2-substituted pyrimidine-5-carboxylic esters is described. The sodium salt of 3,3-dimethoxy-2-methoxycarbonylpropen-1-ol (3) has been found to react with a variety of amidinium salts to afford the corresponding 2-substituted pyrimidine-5-carboxylic esters.
- Zhichkin, Pavel,Fairfax, David J.,Eisenbeis, Shane A.
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p. 720 - 722
(2007/10/03)
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