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Search for "amidine" in Full Text gives 61 result(s) in Beilstein Journal of Organic Chemistry.

Copper-catalyzed aerobic aliphatic C–H oxygenation with hydroperoxides

  • Pei Chui Too,
  • Ya Lin Tnay and
  • Shunsuke Chiba

Beilstein J. Org. Chem. 2013, 9, 1217–1225, doi:10.3762/bjoc.9.138

Graphical Abstract
  • radicals (C-radicals) could be trapped by molecular oxygen to form new C–O bonds. For instance, the Cu-catalyzed aerobic reaction of N-alkylamidines afforded aminidyl radicals (N-radicals) by single-electron oxidation and deprotonation of the amidine moiety, which was followed by 1,5-H-radical shift to
  • generate the corresponding C-radicals (Scheme 1a) [7]. The successive trapping of the resulting C-radicals with molecular O2 forms peroxy radicals (the C–O bond formation). Reduction of peroxy radicals generates alkoxides, cyclization of which with the amidine moiety finally affords dihydrooxazoles
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Published 25 Jun 2013

Selective copper(II) acetate and potassium iodide catalyzed oxidation of aminals to dihydroquinazoline and quinazolinone alkaloids

  • Matthew T. Richers,
  • Chenfei Zhao and
  • Daniel Seidel

Beilstein J. Org. Chem. 2013, 9, 1194–1201, doi:10.3762/bjoc.9.135

Graphical Abstract
  • unselective. It appears that the first oxidation occurs exclusively at the aminal site to form deoxyvasicine (2). The presence of the amidine moiety apparently activates the molecule for oxidation at the benzylic position; we have observed that samples of aminal 7 can remain stable in the freezer for years
  • , whereas 2 begins to convert to 4 within a day when exposed to atmospheric oxygen. Considering this, we reasoned that addition of a weak acid to protonate the relatively basic amidine moiety of 2 might deactivate the benzylic position toward oxidation while not interfering with the initial aminal oxidation
  • was gratifying but somewhat unexpected since Decker reported that samples of the compound completely oxidized to quinazolinone 23 when exposed to air for 24 h [3]. This demonstrates the need for acetic acid to protonate the amidine, preventing further oxidation. While product 16 was obtained in good
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Published 20 Jun 2013

Synthetic studies towards bottromycin

  • Stefanie Ackermann,
  • Hans-Georg Lerchen,
  • Dieter Häbich,
  • Angelika Ullrich and
  • Uli Kazmaier

Beilstein J. Org. Chem. 2012, 8, 1652–1656, doi:10.3762/bjoc.8.189

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  • reactions are described as an excellent synthetic tool for the synthesis of sterically highly hindered endothiopeptides. S-Methylation and subsequent amidine formation can be carried out in an inter- as well as in an intramolecular fashion. The intramolecular approach allows the synthesis of the bottromycin
  • by Schipper [20] and Kaneda [21], based on detailed NMR studies. According to them, the bottromycins are cyclic tetrapeptides, connected to a tripeptidic side chain through an amidine structure. The different bottromycins differ only in the substitution pattern of the proline (Figure 1). The three
  • -dimensional structure was reported recently by Gouda et al. [22]. This structure is quite unusual, not only because of the amidine moiety but also because most amino acids are found in β-methylated form (tert-leucine can be seen as β-methylvaline). Although a series of synthetic studies towards linear
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Published 01 Oct 2012

Synthesis and characterization of Sant-75 derivatives as Hedgehog-pathway inhibitors

  • Chao Che,
  • Song Li,
  • Bo Yang,
  • Shengchang Xin,
  • Zhixiong Yu,
  • Taofeng Shao,
  • Chuanye Tao,
  • Shuo Lin and
  • Zhen Yang

Beilstein J. Org. Chem. 2012, 8, 841–849, doi:10.3762/bjoc.8.94

Graphical Abstract
  • 11e–f had to be constructed through condensation of a protected β-ketoaldehyde with the corresponding amidine. Compound 11e was synthesized from isonicotinonitrile through three steps described previously. Isonicotinonitrile was converted to isonicotinamidine hydrochloride 13 upon reaction in MeOH in
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Published 06 Jun 2012

Chemistry of polyhalogenated nitrobutadienes, 10: Synthesis of highly functionalized heterocycles with a rigid 6-amino-3-azabicyclo[3.1.0]hexane moiety

  • Viktor A. Zapol’skii,
  • Jan C. Namyslo,
  • Armin de Meijere and
  • Dieter E. Kaufmann

Beilstein J. Org. Chem. 2012, 8, 621–628, doi:10.3762/bjoc.8.69

Graphical Abstract
  • chlorides result in the formation of the enamines 11, 12, 13, 16, 25, the amidine 6, and the amides 20, 21, respectively. In the following, cyclization to the highly functionalized pyrazoles 27, 28, pyrimidine 26 and pyridopyrimidine 24 succeeded. Deprotection of 21, 12 and 28 proved to be only partially
  • results in the diaminobutadiene II, which tautomerizes to the stable amidine III. The pyrazoline IV is then formed by an intramolecular SNVin reaction. Finally, HCl elimination affords the pyrazoles 27, 28. The stimulus to investigate such compounds originated from the known pharmacological activities of
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Published 23 Apr 2012

Synthesis, solid-state fluorescence properties, and computational analysis of novel 2-aminobenzo[4,5]thieno[3,2-d]pyrimidine 5,5-dioxides

  • Kenichirou Yokota,
  • Masayori Hagimori,
  • Naoko Mizuyama,
  • Yasuhisa Nishimura,
  • Hiroshi Fujito,
  • Yasuhiro Shigemitsu and
  • Yoshinori Tominaga

Beilstein J. Org. Chem. 2012, 8, 266–274, doi:10.3762/bjoc.8.28

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  • derivative 2,4-diaminoindeno[1,2-d]pyrimidin-5-one; this pyrimidine derivative, which was synthesized by heating a ketene dithioacetal, 2-[bis(methylsulfanyl)methylidene]indan-1,3-dione, under reflux with amine and amidine derivatives in pyridine solution, showed blue-green fluorescence in the solid state [6
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Published 16 Feb 2012

One-pot four-component synthesis of pyrimidyl and pyrazolyl substituted azulenes by glyoxylation–decarbonylative alkynylation–cyclocondensation sequences

  • Charlotte F. Gers,
  • Julia Rosellen,
  • Eugen Merkul and
  • Thomas J. J. Müller

Beilstein J. Org. Chem. 2011, 7, 1173–1181, doi:10.3762/bjoc.7.136

Graphical Abstract
  • , followed by Pd/Cu-catalyzed decarbonylative alkynylation with terminal alkynes 2, and finally by cyclocondensation of the ynone intermediates with substituted amidine hydrochlorides 4, pyrimidylazulenes 5 were obtained in moderate to good yields in a one-pot fashion (Scheme 5) (for experimental details
  • , see Supporting Information File 1). The diversity-oriented nature of this four-component approach to pyrimidylazulenes 5 is underlined by flexible variation of the azulenyl, the alkynyl, and the amidinyl substrates. In particular, the amidine component 4 leads to the formation of aryl (compounds 5a
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Published 26 Aug 2011

An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals

  • Marcus Baumann,
  • Ian R. Baxendale,
  • Steven V. Ley and
  • Nikzad Nikbin

Beilstein J. Org. Chem. 2011, 7, 442–495, doi:10.3762/bjoc.7.57

Graphical Abstract
  • established which gave the desired product in 90% overall yield (Scheme 33). Alternatively, glycine can be reacted with methyl pentanimidate 169 to form the corresponding amidine 171 in high yield. Cyclisation, followed by a Vilsmeier-type reaction then furnishes the key chloroimidazolyl building block 172 in
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Published 18 Apr 2011

C2-symmetric bisamidines: Chiral Brønsted bases catalysing the Diels- Alder reaction of anthrones

  • Deniz Akalay,
  • Gerd Dürner,
  • Jan W. Bats and
  • Michael W. Göbel

Beilstein J. Org. Chem. 2008, 4, No. 28, doi:10.3762/bjoc.4.28

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  • 30 min. The best enantioselectivity, albeit low, was induced by amidine 8c (24% ee). As expected, in the presence of catalyst ent-8d product ent-3a was formed preferentially (Table 1). In a solvent screening using 10 mol% of TBDPS-protected bisamidine 8c, best results were obtained in dichloromethane
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Published 07 Aug 2008

Inversion symmetry and local vs. dispersive interactions in the nucleation of hydrogen bonded cyclic n-mer and tape of imidazolecarboxamidines

  • Sihui Long,
  • Venkatraj Muthusamy,
  • Peter G. Willis,
  • Sean Parkin and
  • Arthur Cammers

Beilstein J. Org. Chem. 2008, 4, No. 23, doi:10.3762/bjoc.4.23

Graphical Abstract
  • acceptors [2]. The intermolecular hydrogen bond between the amidine sp2-NH and the imidazole sp2-N was maintained in all crystalline phases examined. Apparently the sp2-N atom in the imidazole accepts hydrogen bonds better than the sp2-N atom in the amidine group, and the non-involvement of amidine, as the
  • state motif of 2 is likely the Ci dimer and structures that successfully compete with the Ci dimer should have increased stabilities from identifiable atomic parameters. The dihedral angles, θ, between the imidazole and the amidine moieties characterize the solid-state conformation and are reported in
  • Table 1. This parameter is defined in Figure 3 by the amidine N, C atoms and imidazole N, C atoms. With all else equal, molecules with θ of equal value but of opposite sign are conformational enantiomers. Even though only five structures did not crystallize as hydrogen bonded Ci dimers, comparing the
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Published 07 Jul 2008

Perhalogenated pyrimidine scaffolds. Reactions of 5-chloro- 2,4,6-trifluoropyrimidine with nitrogen centred nucleophiles

  • Emma L. Parks,
  • Graham Sandford,
  • John A. Christopher and
  • David D. Miller

Beilstein J. Org. Chem. 2008, 4, No. 22, doi:10.3762/bjoc.4.22

Graphical Abstract
  • , many pyrimidine derivatives have been used for various medicinal applications (Figure 1) [1][2][3]. Synthesis of pyrimidine rings most commonly involves cyclocondensation reactions of amidine, guanidine or thiourea derivatives with either 1,3-diketone or 1,3-diester systems [4][5]. However, many of
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Published 01 Jul 2008
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