N-Heterocyclic carbene/Brønsted acid cooperative catalysis as a powerful tool in organic synthesis

• Rob De Vreese and
• Matthias D’hooghe

Beilstein J. Org. Chem. 2012, 8, 398–402, doi:10.3762/bjoc.8.43

• true as compared to, for example, N-sulfonylimines), N-arylimines are more reactive as compared to N-alkylimines. The question of whether or not N-alkylimines can be deployed successfully in this methodology deserves further elaboration, and may have certain implications with regard to the bioactivity

Computational evidence for intramolecular hydrogen bonding and nonbonding X···O interactions in 2'-haloflavonols

• Tânia A. O. Fonseca,
• Matheus P. Freitas,
• Rodrigo A. Cormanich,
• Teodorico C. Ramalho,
• Cláudio F. Tormena and
• Roberto Rittner

Beilstein J. Org. Chem. 2012, 8, 112–117, doi:10.3762/bjoc.8.12

• interactions; theoretical calculations; Introduction Intermolecular hydrogen bonding (HB) is an interaction governing self-assembly and is responsible for the architecture and organization of molecular aggregates [1], and also ligand–receptor interactions that are responsible for the bioactivity of compounds

Marilones A–C, phthalides from the sponge-derived fungus Stachylidium sp.

• Celso Almeida,
• Stefan Kehraus,
• Miguel Prudêncio and
• Gabriele M. König

Beilstein J. Org. Chem. 2011, 7, 1636–1642, doi:10.3762/bjoc.7.192

• exhibit an equally broad spectrum of bioactivity, including modulation of the central nervous system, protection against brain eschemia, modulation of platelet aggregation and cardiac function, inhibition of smooth muscle cell proliferation, anti-angina activity, and smooth muscle relaxation, as well as

• berghei (see Supporting Information File 1). Interestingly, marilone C (3) showed no activity at 25 µM concentration, indicating that the methyl group 11-CH3 and/or the position of the ketone functionality is essential for this bioactivity. Marilones A, B, and C (1–3) were also tested for cytotoxic

• at the University of North Carolina at Chapel Hill and Project Officer Jamie Driscol at NIMH, Bethesda MD, USA; we kindly thank also the remaining antiviral bioactivity tests performed by the U.S. National Institute of Health drug discovery program, which were supported by contracts NO1-A1-30048

Natural product biosyntheses in cyanobacteria: A treasure trove of unique enzymes

• Jan-Christoph Kehr,
• Douglas Gatte Picchi and
• Elke Dittmann

Beilstein J. Org. Chem. 2011, 7, 1622–1635, doi:10.3762/bjoc.7.191

• bioactivity-guided screening techniques towards cytotoxic, multidrug-resistance reversal, antiprotease, antifungal and antiviral activities [5]. Many bioactive metabolites possess a peptide or a macrolide structure, or a combination of both types [6][7][8]. Other metabolites belong to the alkaloid class of

• , including many that are not or only rarely seen in other microorganisms. The potential of cyanobacteria for natural product research thus goes far beyond the exploitation of the bioactivity of the products. Knowledge about the biochemistry of unique enzymes is particularly valuable for synthetic biology

Synthesis of (−)-julocrotine and a diversity oriented Ugi-approach to analogues and probes

• Ricardo A. W. Neves Filho,
• Bernhard Westermann and
• Ludger A. Wessjohann

Beilstein J. Org. Chem. 2011, 7, 1504–1507, doi:10.3762/bjoc.7.175

• be considered a privileged structural element for bioactivity. Results and Discussion The synthetic approach, illustrated in Scheme 1, starts from Cbz-glutamine 2, which reacted in the presence of dicyclohexylcarbodiimide (DCC) and N-hydroxysuccinimide (NHS) in DMF to afford Cbz-glutarimide 3 in 76

α,β-Aziridinylphosphonates by lithium amide-induced phosphonyl migration from nitrogen to carbon in terminal aziridines

• David. M. Hodgson and
• Zhaoqing Xu

Beilstein J. Org. Chem. 2010, 6, 978–983, doi:10.3762/bjoc.6.110

• acids; aziridines; lithiation; migration; synthetic methods; Introduction The synthesis of aminophosphonic acids and their derivatives has attracted considerable attention, since the presence of such functionality, typically as amino acid surrogates, leads to interesting bioactivity in, for example

Synthesis of gem-difluoromethylenated analogues of boronolide

• Jing Lin,
• Xiao-Long Qiu and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2010, 6, No. 37, doi:10.3762/bjoc.6.37

• demonstrated that the α,β-unsaturated-δ-lactone moiety plays a key role in the bioactivity of many natural products. This is due to the fact that this unit is an excellent potential Michael acceptor for nucleophilic amino acid residues of the natural receptors interacting with these compounds [16][17][18

Functional properties of metallomesogens modulated by molecular and supramolecular exotic arrangements

• Alessandra Crispini,
• Mauro Ghedini and
• Daniela Pucci

Beilstein J. Org. Chem. 2009, 5, No. 54, doi:10.3762/bjoc.5.54

• going to the tetrahedral [Zn(II)] and pentacoordinate Ga(III) to obtain novel, non conventional structures. Moreover, by changing the nature of coordinating ligands and the kinds of substituents, further properties such as luminescence and bioactivity can be promoted at the same time, leading to smart

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33

• : antitumour; bioactivity; mitomycin; mitosene; synthesis; Review Introduction The mitomycins pose unique challenges to the synthetic chemist. As S. Danishefsky noted, “The complexity of the problem arises from the need to accommodate highly interactive functionality in a rather compact matrix and to

An expedient synthesis of 5-n-alkylresorcinols and novel 5-n-alkylresorcinol haptens

• Kirsti Parikka and
• Kristiina Wähälä

Beilstein J. Org. Chem. 2009, 5, No. 22, doi:10.3762/bjoc.5.22

• ][17][18][19][20][21]. However, AR are not generally nor readily available. Thus an efficient preparation method is needed for various analytical, metabolic or bioactivity investigations. The critical step in the synthesis of long alkyl chain (≥C15) AR is the formation of C–C bond between the aromatic

Sordarin, an antifungal agent with a unique mode of action

• Huan Liang

Beilstein J. Org. Chem. 2008, 4, No. 31, doi:10.3762/bjoc.4.31

• fungi by stabilizing the ribosome/EF2 complex. This mode of action is in contrast to typical antifungals, which target the cell membrane. This unusual bioactivity makes sordarin a promising candidate for the development of new fungicidal agents, and provided the motivation for extensive research. Three

• total syntheses (by the Kato, Mander and Narasaka groups), modifications of the glycosyl unit, and changes to the diterpene core (Cuevas and Ciufolini models) will also be discussed in this review. Keywords: antifungal; bioactivity; sordaricin; sordarin; total synthesis; Introduction For

Themed series in organo- fluorine chemistry

• David O'Hagan

Beilstein J. Org. Chem. 2008, 4, No. 11, doi:10.3762/bjoc.4.11

• practiced particularly when tuning the properties of molecules for specialist functions. Of particular prominence is the role fluorine substitution finds in pharmaceutical development [1], and selective fluorination has made a major contribution to the bioactivity of a wide range of agrochemical products [2