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Search for "dihydropyridazine" in Full Text gives 5 result(s) in Beilstein Journal of Organic Chemistry.

Trifluoromethylated hydrazones and acylhydrazones as potent nitrogen-containing fluorinated building blocks

  • Zhang Dongxu

Beilstein J. Org. Chem. 2023, 19, 1741–1754, doi:10.3762/bjoc.19.127

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  • . Keywords: acylhydrazones; difluoromethylation; dihydropyridazine; fluorinated building blocks; hydrazones; imidazolidines; pyrazoles; pyrazolidines; pyrazolines; trifluoromethylation; Introduction The introduction of fluorine into pharmaceuticals, agrochemicals, and materials can significantly enhance
  • programs. Synthesis of trifluoromethylpyrazoles from trifluoroacetaldehyde hydrazones. Synthesis of polysubstituted pyrazolidines and pyrazolines. Asymmetric synthesis of 3-trifluoromethyl-1,4-dihydropyridazines reported by Rueping et al. [39]. Synthesis of 3-trifluoromethyl-1,4-dihydropyridazine with
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Published 15 Nov 2023

Chemical approaches to discover the full potential of peptide nucleic acids in biomedical applications

  • Nikita Brodyagin,
  • Martins Katkevics,
  • Venubabu Kotikam,
  • Christopher A. Ryan and
  • Eriks Rozners

Beilstein J. Org. Chem. 2021, 17, 1641–1688, doi:10.3762/bjoc.17.116

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  • nucleic acid chemists, a universal solution to triple helical pyrimidine recognition is still missing [94][109]. Nielsen and co-workers introduced 3-oxo-2,3-dihydropyridazine (E, Figure 7), a synthetic nucleobase designed to form a single hydrogen bond with U in PNA–DNA–PNA clamps [110]. Their design
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Published 19 Jul 2021

Synthesis of dibenzosuberenone-based novel polycyclic π-conjugated dihydropyridazines, pyridazines and pyrroles

  • Ramazan Koçak and
  • Arif Daştan

Beilstein J. Org. Chem. 2021, 17, 719–729, doi:10.3762/bjoc.17.61

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  • Ramazan Kocak Arif Dastan Department of Chemistry, Faculty of Sciences, Atatürk University, Erzurum, 25240, Turkey 10.3762/bjoc.17.61 Abstract The synthesis of novel polycyclic π-conjugated dihydropyridazines, pyridazines, and pyrroles was studied. Dihydropyridazine dyes were synthesized by
  • inverse electron-demand Diels–Alder cycloaddition reactions between a dibenzosuberenone and tetrazines that bear various substituents. The pyridazines were synthesized in high yields by oxidation of dihydropyridazine-appended dibenzosuberenones with PIFA or NO. p-Quinone derivatives of pyridazines were
  • classic organic dyestuffs. In that study, two highly fluorescent dibenzosuberenone-based dihydropyridazine dyes, 3a,b, were synthesized, and it was found that they can be used as a selective and sensitive sensor of fluoride anions (Scheme 1, Table 1) [55]. In another work, we reported the design
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Published 15 Mar 2021

Hydrazides in the reaction with hydroxypyrrolines: less nucleophilicity – more diversity

  • Dmitrii A. Shabalin,
  • Evgeniya E. Ivanova,
  • Igor A. Ushakov,
  • Elena Yu. Schmidt and
  • Boris A. Trofimov

Beilstein J. Org. Chem. 2021, 17, 319–324, doi:10.3762/bjoc.17.29

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  • saturated pyridazine scaffolds is both highly topical and necessary. Recently, we have developed a convenient approach to the 1,4-dihydropyridazine core based on the Brønsted acid-catalyzed regioselective recyclization of 5-hydroxypyrrolines (assembled in a one-pot manner from ketoximes and acetylene gas [8
  • -dihydropyridazine 4aa was not detected at all (Table 1, entry 1). Although the increase of the reaction time up to 5 h slightly improved the yield of tetrahydropyridazine 3aa (53%, entry 2 in Table 1), more efficient appeared to be the use of a two-fold excess of benzohydrazide (2a) that provided 3aa in 93
  • % isolated yield after reflux for 3 h (Table 1, entry 4). With these optimal conditions for the synthesis of tetrahydropyridazine 3aa in hand, we next turned our attention to its transformation to 1,4-dihydropyridazine 4aa. Both the prolonged reflux for 6 h (Table 1, entry 5) and the addition of 100 mol % of
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Published 29 Jan 2021

Mechanistic studies of an L-proline-catalyzed pyridazine formation involving a Diels–Alder reaction with inverse electron demand

  • Anne Schnell,
  • J. Alexander Willms,
  • S. Nozinovic and
  • Marianne Engeser

Beilstein J. Org. Chem. 2019, 15, 30–43, doi:10.3762/bjoc.15.3

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  • + 2] cycloaddition with the electron-poor tetrazine forming a tetraazabicyclo[2.2.2]octadiene derivative which then eliminates N2 in a retro-Diels–Alder reaction to yield a 4,5-dihydropyridazine species. The reaction was studied in three variants: unmodified, with a charge-tagged substrate, and with a
  • –Alder reaction by eliminating dinitrogen. This leads to the dihydropyridazine intermediate III out of which the catalyst is released to yield the pyridazine product 3 [51]. Shihab et al. later studied a related reaction of a series of dienophiles with dimethyl 1,2,4,5-tetrazine-3,6-dicarboxylate by
  • theoretical methods [52]. Their results are in agreement with the catalytic cycle presented in Scheme 1. However, the question is raised whether the bicyclic Diels–Alder species II is a real intermediate or rather a transition state of a concerted formation of the dihydropyridazine intermediate III directly
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Published 03 Jan 2019
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