17180-93-7Relevant articles and documents
Spectroscopic evidence for participation of the 1′,4′-imino tautomer of thiamin diphosphate in catalysis by yeast pyruvate decarboxylase
Jordan, Frank,Zhang, Zhen,Sergienko, Eduard
, p. 188 - 198 (2002)
The 1′,4′-iminopyrimidine tautomeric form of the coenzyme thiamin diphosphate (ThDP), implicated in catalysis on the basis of the conformation of enzyme-bound ThDP, has been observed by both ultraviolet absorption and circular dichroism spectroscopy. On yeast pyruvate decarboxylase, the unusual tautomer is observed in an active center variant in which catalysis in the post-decarboxylation regime of the reaction is compromised. In a model system consisting of N1-methyl-4-aminopyrimidinium or N1-methyl-N4-n-butylpyrimidinium salts, on treatment with either NaOH in water, or DBU in DMSO there is an intermediate formed with λmax near 310 nm, and this intermediate reverts back to the starting salt on acidification. Proton NMR chemical shifts are consistent with the intermediate representing the 1-methyl-4-imino tautomer. On the enzyme, the intermediate could be observed by rapid-scan stopped flow with UV detection when reacting holoenzyme of the E477Q active center variant with pyruvate, and by circular dichroism even in the absence of pyruvate. This represents the first direct observation of the imino tautomeric form of ThDP both on the enzyme and in models, although some years ago, this laboratory had already reported some pertinent acid-base properties for its formation [Jordan, F., and Mariam, Y. H. (1978) J. Am. Chem. Soc. 100, 2534-2541]. The work also represents the first instance in which a rare tautomer implicated in catalysis is identified and suggests that such tautomeric catalysis may be more common in biology than hitherto recognized.
Synthesis and biological evaluation of potential inhibitors of the cysteine proteases cruzain and rhodesain designed by molecular simplification
Braga, Saulo Fehelberg Pinto,Martins, Luan Carvalho,da Silva, Elany Barbosa,Sales Júnior, Policarpo Ademar,Murta, Silvane Maria Fonseca,Romanha, Alvaro José,Soh, Wai Tuck,Brandstetter, Hans,Ferreira, Rafaela Salgado,de Oliveira, Renata Barbosa
supporting information, p. 1889 - 1900 (2017/03/08)
Analogues of 8-chloro-N-(3-morpholinopropyl)-5H-pyrimido[5,4-b]indol-4-amine 1, a known cruzain inhibitor, were synthesized using a molecular simplification strategy. Five series of analogues were obtained: indole, pyrimidine, quinoline, aniline and pyrrole derivatives. The activity of the compounds was evaluated against the enzymes cruzain and rhodesain as well as against Trypanosoma cruzi amastigote and trypomastigote forms. The 4-aminoquinoline derivatives showed promising activity against both enzymes, with IC50values ranging from 15 to 125?μM. These derivatives were selective inhibitors for the parasitic proteases, being unable to inhibit mammalian cathepsins B and S. The most active compound against cruzain (compound 5a; IC50?=?15?μM) is considerably more synthetically accessible than 1, while retaining its ligand efficiency. As observed for the original lead, compound 5a was shown to be a competitive enzyme inhibitor. In addition, it was also active against T. cruzi (IC50?=?67.7?μM). Interestingly, the pyrimidine derivative 4b, although inactive in enzymatic assays, was highly active against T. cruzi (IC50?=?3.1?μM) with remarkable selectivity index (SI?=?128) compared to uninfected fibroblasts. Both 5a and 4b exhibit drug-like physicochemical properties and are predicted to have a favorable ADME profile, therefore having great potential as candidates for lead optimization in the search for new drugs to treat Chagas disease.
PYRIMIDINE DERIVATIVES AND HERBICIDES CONTAINING THE SAME
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, (2008/06/13)
The present invention provides a pyrimidine derivative represented by the formula: wherein R1p and R1q are the same or different, and each represents (1)hydrogen, (2)halogen, (3) a C1-6alkyl group which may be substituted or (4) a C1-6alkoxy group, and so on, R2 is halogen, a C1-6alkyl group, cyano group, and so on, Ar is a phenyl group which may be substituted or is a condensed hetero ring which may be substituted, which has excellent selective herbicidal activity, and a herbicide containing the derivative.
