13509-52-9Relevant articles and documents
Photoinduced electron transfer to pyrimidines and 5,6-dihydropyrimidine derivatives: Reduction potentials determined by fluorescence quenching kinetics
Scannell, Michael P.,Prakash, Gautam,Falvey, Daniel E.
, p. 4332 - 4337 (1997)
The dynamics of flourescence quenching of excited state electron donor sensitizers by various pyrimidine and 5,6-dihydropyrimidine substrates was examined. For all of the substrates studied the rate constant of fluorescence quenching (kq) increases as the excited state oxidation potential (Eox*) becomes more negative. The dependence of kq on Eox* in each case is well described by the Rehm-Weller relationship. Fits of the data to this relationship allow for the estimation of the reduction potentials of the substrates (Ered). The pyrimidines 1,3-dimethylthymine, 1,3-dimethyluracil, and 1,3,6-trimethyluracil give Ered values (in CH3CN) ranging from -2.06 (vs SCE) to -2.14 V. Their dihydro derivatives, 1,3-dimethyl-5,6-dihydrothymine, 1,3-dimethyl-5,6-dihydrouracil, and 1,3,6-trimethyl-5,6-dihydrouracil gave Ered values ranging from -1.90 to -2.07 V. The higher Ered values for the dihydropyrimidines compared with their unsaturated derivatives is attributed to aromatic stabilization in the pyrimidines, which is not present in the dihydro derivatives. In addition, the Ered for both the trans-syn and cis-syn diastereomers of the dimethylthymine cyclobutane dimer was examined using the same method. The trans-syn dimer gives an Ered of -1.73 V and the cis-syn dimer gives an Ered of -2.20 V. This remarkable difference is attributed to a stereoelectronic effect. The cis-syn dimer anion radical suffers from an unfavorable charge-dipole interaction between the added electron and the O4 carbonyl group in the remaining pyrimidine ring. In contrast, the trans-syn dimer anion radical shows mainly a stabilizing inductive electron-withdrawing effect of the remaining O4 carbonyl group. Solvent effects on Ered were also examined. It is shown that the protic solvent, CH3OH, significantly stabilizes the anion radicals, raising Ered by ca. 400 mV over the value in CH3CN.
Antiparasitic activity of highly conjugated pyrimidine-2,4-dione derivatives
Azas, Nadine,Rathelot, Pascal,Djekou, Serge,Delmas, Florence,Gellis,Di Giorgio, Carole,Vanelle, Patrice,Timon-David, Pierre
, p. 1263 - 1270 (2003)
4-[2-(1,3-Dimethyl-5-nitro-2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-yl) vinyl]benzaldehyde was synthesized in four steps from 6-methyl-1H,3H-pyrimidine- 2,4-dione. This aldehyde was functionalized by various substituted anilines or substituted benzylamines. Antiparasitic activities of the corresponding azomethines were assessed against Plasmodium falciparum, Trichomonas vaginalis and Leishmania infantum compared to their toxicity versus human cells.
Hetero-Diels-Alder cycloadditions of α,β-unsaturated acyl cyanides. Part 2. Reactions with N,N-dimethyluracils, a new route to 5-substituted uracil derivatives
Zhuo,Wyler
, p. 1916 - 1927 (1993)
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Case,Hill
, p. 1536,1540 (1930)
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Khattak,Wang
, p. 945,946,950,951-953 (1972)
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Highly Efficient Synthesis of Substituted 3,4-Dihydropyrimidin-2-(1H)-ones (DHPMs) Catalyzed by Hf(OTf)4: Mechanistic insights into reaction pathways under metal Lewis acid catalysis and solvent-free conditions
Kong, Rui,Han, Shuai-Bo,Wei, Jing-Ying,Peng, Xiao-Chong,Xie, Zhen-Biao,Gong, Shan-Shan,Sun, Qi
, (2019/02/01)
In our studies on the catalytic activity of Group IVB transition metal Lewis acids, Hf(OTf)4 was identified as a highly potent catalyst for”one-pot, three-component” Biginelli reaction. More importantly, it was found that solvent-free conditions, in contrast to solvent-based conditions, could dramatically promote the Hf(OTf)4-catalyzed formation of 3,4-dihydro-pyrimidin-2-(1H)-ones. To provide a mechanistic explanation, we closely examined the catalytic effects of Hf(OTf)4 on all three potential reaction pathways in both “sequential bimolecular condensations” and “one-pot, three-component” manners. The experimental results showed that the synergistic effects of solvent-free conditions and Hf(OTf)4 catalysis not only drastically accelerate Biginelli reaction by enhancing the imine route and activating the enamine route but also avoid the formation of Knoevenagel adduct, which may lead to an undesired byproduct. In addition, 1H-MMR tracing of the H-D exchange reaction of methyl acetoacetate in MeOH-d4 indicated that Hf(IV) cation may significantly accelerate ketone-enol tautomerization and activate the β-ketone moiety, thereby contributing to the overall reaction rate.
Intermediates for macrocyclic compounds
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Page/Page column 33; Sheet 10, (2015/11/30)
The present invention is directed to novel macrocyclic compounds of formula (I) and their pharmaceutically acceptable salts, hydrates or solvates: wherein R1, R2, R3, R4, R5, R6, n1, m, p Z1, Z2, and Z3 are as describe in the specification. The invention also relates to compounds of formula (I) which are antagonists of the motilin receptor and are useful in the treatment of disorders associated with this receptor and with or with motility dysfunction.
