Mostrando 521 - 540 Resultados de 4,819 Para Buscar 'Pirimidina~', tiempo de consulta: 4.81s Limitar resultados
  1. 521
  2. 522
    “…A number of 18-nor-5α-androsta-2,13-diene[3,2-d]pyrimidine, androsta-2-ene[3,2-d]pyrimidine, Δ(1, 3, 5(10))-estratrieno[16,17-d]pyrimidine, and 17-chloro-16-dihydrotriazine steroids were synthesized by condensations of amidines with β-chlorovinyl aldehydes derived from natural hormones. …”
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  3. 523
    por Maiti, Amit K, Brahmachari, Samir K
    Publicado 2001
    “…BACKGROUND: Poly purine.pyrimidine sequences have the potential to adopt intramolecular triplex structures and are overrepresented upstream of genes in eukaryotes. …”
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  4. 524
    “…The current findings suggest that the 3-benzoyl imidazo[1,2-a]pyrimidine derivatives, herein synthesized by an accessible methodology, are potential antifungal drugs.…”
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  5. 525
    “…Here, we examine the dynamic properties of poly-pyrimidine bulges of varying length (n = 1–4, 7) across a range of Mg(2+) concentrations using HIV-1 TAR RNA as a model system and solution NMR spectroscopy. …”
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  6. 526
    “…Hexamethyldisilazane was then added to perform heterocyclization to produce the corresponding pyrazolo[3,4-d]pyrimidines in suitable yields. These one-flask reactions thus involved Vilsmeier amidination, imination reactions, and the sequential intermolecular heterocyclization. …”
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  7. 527
    por Wu, Liqiang, Liu, Yunxia, Li, Yazhen
    Publicado 2018
    “…A series of novel spirooxindole-O-naphthoquinone-tetrazolo[1,5-a]pyrimidine hybrids were designed, synthesized and evaluated as potent antitumor agents. …”
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  8. 528
    “…The pyrazole-o-aminonitriles (3a-c) were in turn used as precursors for the preparation of previously unreported 1-[6-(p-tolyl)-pyridazin-3-yl]pyrazolo[3,4-d]pyrimidines (8, 9, 13-20) and 7-[6-( p-tolyl) pyridazin-3-yl]2-arylpyrazolo[3,4-d]1,2,4-triazolo[5,1-f]pyrimidines (10-12) which are expected to possess considerable chemical and pharmacological activities.…”
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  9. 529
    “…The synthetic route for introduction of fluorophenylalkyl (compounds 5, 7, 14 and 15) and fluorophenylalkenyl (compounds 4E and 13) side chains at C-6 of the pyrimidine nucleus involved the lithiation of the pyrimidine derivatives 1, 2 and 11 and subsequent nucleophilic addition or substitution reactions of the organolithium intermediate thus obtained with 2-fluorophenylacetone, 4-fluoroacetophenone or ethyl 4-fluorobenzoate as electrophiles. …”
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  10. 530
    “…One pot synthesis of 1-arylpyrazolo[3,4-d]pyrimidin-4-ones by the reaction of 5-amino-N-substituted-1H-pyrazole-4-carbonitrile with different lower aliphatic acids in the presence of POCl(3) has been developed(.) …”
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  11. 531
  12. 532
    “…A series of pyrido[2,3-d]pyrimidine derivatives were designed and synthesized based on known CC chemokine receptor 4 (CCR4) antagonists. …”
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  13. 533
    “…Condensation of pyrazoloxazine derivative 3 with 99% hydrazine hydrate afforded the 5-aminopyrazolo[3,4-d]pyrimidine derivative 9. Coupling of 9 with aromatic aldehydes yielded a series of 3,6-dimethyl-5-(4-substitutedbenzylideneamino)-1-phenyl-1,5-dihydropyrazolo[3,4-d]pyrimidin-4-ones 10a–e. …”
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  14. 534
    “…Bromination of N-substituted homophthalimides and tetrahydropyrido[4,3-d]-pyrimidine-5,7-diones produces 4,4-dibromohomophthalimide and 8,8-dibromo-tetrahydropyrido[4,3-d]pyrimidine-5,7-dione derivatives, respectively, that can be used as precursors for spiro derivatives. …”
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  15. 535
    “…We synthesized eleven COX-2 inhibitors based on a 2(4-methylsulfonylphenyl)pyrimidine core from which we selected three as prospective PET radioligands based on desirable factors, such as high inhibitory potency for COX-2, very low inhibitory potency for COX-1, moderate lipophilicity, and amenability to labeling with a positron-emitter. …”
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  16. 536
    por Choi, Yoona, Kim, Heejun, Park, Seung Bum
    Publicado 2018
    “…To address these issues, we developed a new divergent synthetic pathway for skeletally distinct pyrimidine-containing medium-sized azacycles. We introduced N-quaternized pyrimidine-containing polyheterocycles as novel key intermediates for diversity-generating reactions via selective bond cleavages or migrations and prepared 14 discrete core skeletons in an efficient manner. …”
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  17. 537
    “…A new series of pyrazole 4–7 and pyrazolo[1,5-a]pyrimidine 8–13 were synthesized by using a simple, efficient procedure, and screened for their in-vitro antimicrobial and antitumor activities. …”
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  18. 538
  19. 539
    “…The pyrimidine metabolism pathway has important biological functions; it not only maintains appropriate pyrimidine pools but also produces bioactive intermediate metabolites. …”
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  20. 540
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