Synthesis of the B-seco limonoid core scaffold

• Hanna Bruss,
• Hannah Schuster,
• Rémi Martinez,
• Markus Kaiser,
• Andrey P. Antonchick and
• Herbert Waldmann

Beilstein J. Org. Chem. 2014, 10, 194–208, doi:10.3762/bjoc.10.15

• modulators [26]. B-seco limonoids constitute exceptionally challenging synthesis targets, as the characteristic structural features are a compact, highly oxygenated as well as richly decorated framework and stereochemically dense functionalization. In all B-seco limonoids an A ring is linked by a C–C bond to

Total synthesis of (+)-grandiamide D, dasyclamide and gigantamide A from a Baylis–Hillman adduct: A unified biomimetic approach

• Andivelu Ilangovan and
• Shanmugasundar Saravanakumar

Beilstein J. Org. Chem. 2014, 10, 127–133, doi:10.3762/bjoc.10.9

• additional functional groups on them by replacing the starting materials by activated alkenes and aldehydes. Various multifunctional molecules including natural products have already been successfully synthesized using the Baylis–Hillman adducts [9]. Structural features of grandiamide D, gigantamide A

Studies on the interaction of isocyanides with imines: reaction scope and mechanistic variations

• Ouldouz Ghashghaei,
• Consiglia Annamaria Manna,
• Esther Vicente-García,
• Marc Revés and
• Rodolfo Lavilla

Beilstein J. Org. Chem. 2014, 10, 12–17, doi:10.3762/bjoc.10.3

• ring system. The scope of the reaction regarding the imine and isocyanide ranges has been determined, and also some mechanistic variations and structural features have been described. Keywords: azetidines; heterocycles; imines; isocyanides; multicomponent reactions; Introduction The interaction of

• Discussion Reaction scope In this section we analyze the reaction conditions, the structural features of the products and the scope of the reactants. Reaction conditions We began our studies with the experimental screening of the solvents, catalysts and temperatures suitable for this transformation. In this

• monocrystal of the bis(imino)azetidine 3a was subjected to X-ray diffraction analysis and the solid state structure is depicted in Figure 1 [11]. This result confirms the structural features associated to this scaffold, and also raises some questions on the origin of the stereochemistry associated to the C=N

Novel supramolecular affinity materials based on (−)-isosteviol as molecular templates

• Christina Lohoelter,
• Malte Brutschy,
• Daniel Lubczyk and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2013, 9, 2821–2833, doi:10.3762/bjoc.9.317

• requirements for the formation of C3-symmetric architectures with extended cavities. Due to their structural features, triptycenes have found widespread application in organic synthesis: Ranging from polymer sciences [41], materials for gas storage [42][43][44][45][46][47][48][49][50], (organo)catalysis [51

• additional base and operation in a sealed tube provided a satisfactory yield of 8 (Scheme 3) [61]. By molecular modelling the structural features can be visualized (Figure 5). A relatively closed C3-symmetric cleft is formed by all-syn-8 (Figure 5a), whereas the less symmetric anti,anti,syn-8 (Figure 5b

• compounds, see Supporting Information File 1. Unique structural features of (−)-isosteviol. Triphenylene ketal based on (−)-isosteviol. Structural features of triptycene derivatives. Hexaammoniumtriptycene hexachloride 4 and 15-oxo-derivatives 5a–c of (–)-isosteviol. Molecular modelling structures (Spartan

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

• . Interestingly all these compounds are actually pro-drugs hence the common structural features can be rationalised as the molecules undergo an acid-catalysed Smiles-rearrangement prior to bioconjugation to ATPases (Scheme 6). Most of the synthetic routes towards the embedded pyridine heterocycle in these

• structures of pioglitazone and rosiglitazone show common structural features bearing a distal pyridine ring linked to the thiazolidinedione pharmacophore. In rosiglitazone the pyridine unit is introduced via an SNAr reaction between N-methylethanolamine (1.44) and 2-chloropyridine (1.43) which in turn is

Elucidation of the regio- and chemoselectivity of enzymatic allylic oxidations with Pleurotus sapidus – conversion of selected spirocyclic terpenoids and computational analysis

• Verena Weidmann,
• Mathias Schaffrath,
• Holger Zorn,
• Julia Rehbein and
• Wolfgang Maison

Beilstein J. Org. Chem. 2013, 9, 2233–2241, doi:10.3762/bjoc.9.262

• evaluate the DFT-energies in terms of relative and absolute values. For this comparison CBS-QB3 has been applied to model structures 11A and 11B that contain key structural features of 11 and 12 (Table 1). According to the data summarized in Table 1 and Table 2 B3LYP/6-31+G** gives reasonable results and

The chemistry of isoindole natural products

• Klaus Speck and
• Thomas Magauer

Beilstein J. Org. Chem. 2013, 9, 2048–2078, doi:10.3762/bjoc.9.243

Self-assembly of 2,3-dihydroxycholestane steroids into supramolecular organogels as a soft template for the in-situ generation of silicate nanomaterials

• Valeria C. Edelsztein,
• Andrea S. Mac Cormack,
• Matías Ciarlantini and
• Pablo H. Di Chenna

Beilstein J. Org. Chem. 2013, 9, 1826–1836, doi:10.3762/bjoc.9.213

• structure–property relationships, it is still impossible to design a new LMOG de novo. For those reasons most of the known LMOGs have been discovered serendipitously. Nevertheless, with the knowledge gained about the mode of aggregation of LMOG molecules some of the structural features necessary for

Organocatalyzed enantioselective desymmetrization of aziridines and epoxides

• Ping-An Wang

Beilstein J. Org. Chem. 2013, 9, 1677–1695, doi:10.3762/bjoc.9.192

• -oxide, and N-heterocyclic carbenes were published. However, the enantioselective ring-opening of meso-aziridines in the presence of chiral organocatalysts (OC) has emerged as a research field only in recent years. The organocatalysts utilized in these processes are diverse in their structural features

True and masked three-coordinate T-shaped platinum(II) intermediates

• Manuel A. Ortuño,
• Salvador Conejero and
• Agustí Lledós

Beilstein J. Org. Chem. 2013, 9, 1352–1382, doi:10.3762/bjoc.9.153

• position is occupied by a very weak ligand (agostic bond, solvent molecule or counteranion), which can be easily displaced. This review summarizes the structural features of the true and masked T-shaped Pt(II) complexes reported so far and describes synthetic strategies employed for their formation

• -coordinate complexes to distinguish them from the true low-coordinate complexes. In this review, we will summarize recent advances in true and masked three-coordinate Pt(II) complexes, highlighting both their structural features and their possible participation as reaction intermediates. Computational

• , the structural features of the main families of these compounds will be summarized. The next sections will be devoted to the spectroscopic tools for their detection and the synthetic strategies employed to their formation. Afterwards, the rearrangement processes exhibited by the low-coordinate

Anionic cascade reactions. One-pot assembly of (Z)-chloro-exo-methylenetetrahydrofurans from β-hydroxyketones

• István E. Markó and
• Florian T. Schevenels

Beilstein J. Org. Chem. 2013, 9, 1319–1325, doi:10.3762/bjoc.9.148

• , possessing unique structural features. Keywords: acetylene addition; dichloroethylene; dimerisation; dioxanes; tetrahydrofurans; Introduction Recently, we have shown that simple ketones reacted with 1,1-dichloroethylene, in the presence of potassium tert-butoxide, to afford rare (Z)-chloro-exo

Methylidynetrisphosphonates: Promising C₁ building block for the design of phosphate mimetics

• Vadim D. Romanenko and
• Valery P. Kukhar

Beilstein J. Org. Chem. 2013, 9, 991–1001, doi:10.3762/bjoc.9.114

• salts (Figure 1) [7]. Structural features of the trisphosphonate 18 were studied by NMR spectroscopy and by single-crystal X-ray diffraction. Only one 31P NMR signal is observable for three equivalent phosphonate moieties in CHCl3. In contrast, the 31P solid-state NMR spectrum of 18 revealed three

Thioester derivatives of the natural product psammaplin A as potent histone deacetylase inhibitors

• Matthias G. J. Baud,
• Thomas Leiser,
• Vanessa Petrucci,
• Mekala Gunaratnam,
• Stephen Neidle,
• Franz-Josef Meyer-Almes and
• Matthew J. Fuchter

Beilstein J. Org. Chem. 2013, 9, 81–88, doi:10.3762/bjoc.9.11

• , we [20] and others [21] reported an in-depth structure–activity relationship of this natural product against its HDAC targets. Dissection of its activity against a panel of HDACs allowed us to highlight structural features responsible for its high inhibitory potency and selectivity. In particular, we

Bioactive selaginellins from Selaginella tamariscina (Beauv.) Spring

• Chao Yang,
• Yutian Shao,
• Kang Li and
• Wujiong Xia

Beilstein J. Org. Chem. 2012, 8, 1884–1889, doi:10.3762/bjoc.8.217

• E-ring, and one ABMN system (δH 7.61, 7.42, 6.41 and 6.35, each 1H, d, J = 10.0 Hz) for the C-ring. The above structural features suggested 1 was a selaginellin with a formyl group. Key evidence for the structure of 1 obtained from the HMBC experiment further confirmed this suggestion (Figure 2

The crystal structure of the Dess–Martin periodinane

• Albert Schröckeneder,
• Desiree Stichnoth,
• Peter Mayer and
• Dirk Trauner

Beilstein J. Org. Chem. 2012, 8, 1523–1527, doi:10.3762/bjoc.8.172

• ) crystallizes in a triclinic unit cell, which is occupied by two molecules. An ORTEP plot and numbering scheme for monomeric DMP (1) with 50% probability ellipsoids is shown in Figure 2. Important bond lengths and angles are provided in Table 1. Several structural features of monomeric 1 are noteworthy. The

Synthesis of diverse indole libraries on polystyrene resin – Scope and limitations of an organometallic reaction on solid supports

• Kerstin Knepper,
• Sylvia Vanderheiden and
• Stefan Bräse

Beilstein J. Org. Chem. 2012, 8, 1191–1199, doi:10.3762/bjoc.8.132

• distinctive structural features of indole moieties prompted us to investigate the scope and limitations of this reaction. In this paper, we describe our various strategies towards synthesis of the indole core. A solid-phase Bartoli reaction on solid supports is advantageous due to the decreased number of

Similarity analysis, synthesis, and bioassay of antibacterial cyclic peptidomimetics

• Workalemahu M. Berhanu,
• Mohamed A. Ibrahim,
• Girinath G. Pillai,
• Alexander A. Oliferenko,
• Levan Khelashvili,
• Farukh Jabeen,
• Bushra Mirza,
• Farzana Latif Ansari,
• Ihsan ul-Haq,
• Said A. El-Feky and
• Alan R. Katritzky

Beilstein J. Org. Chem. 2012, 8, 1146–1160, doi:10.3762/bjoc.8.128

• hyperspace was performed by using STATISTICA version 6 software [58], with Euclidean distance and other metrics used as similarity measures. Cluster analysis guided by the experimental MIC available for some compounds should help reveal structural features affording antibacterial activity and to identify

• hotspots in the descriptor hyperspace. Combinations of structural features in such hotspots can be used as guidelines for the rational design of cyclic peptide structures to achieve desirable levels of antibacterial activity. Molecular-descriptor-based cluster analysis; single-linkage Euclidean distances

Synthesis of new pyrrole–pyridine-based ligands using an in situ Suzuki coupling method

• Matthias Böttger,
• Björn Wiegmann,
• Steffen Schaumburg,
• Peter G. Jones,
• Wolfgang Kowalsky and
• Hans-Hermann Johannes

Beilstein J. Org. Chem. 2012, 8, 1037–1047, doi:10.3762/bjoc.8.116

• target structures 1–3 were successfully synthesized in good to acceptable yields by applying an in situ variation of the Suzuki coupling as the main reaction step. The crystal structures of these compounds could be obtained by X-ray analysis. They exhibit interesting, but very different structural

• features: 1 forms chains that consist of molecules directly interconnected by N–H…N hydrogen bonds, whereas 2 retains the solvent molecule methanol in the “bay” region of the molecule to form stacked dimers. Structure 3 forms a chain-like structure, but retains the solvent molecule ethanol, which connects

Recent advances towards azobenzene-based light-driven real-time information-transmitting materials

• Jaume García-Amorós and
• Dolores Velasco

Beilstein J. Org. Chem. 2012, 8, 1003–1017, doi:10.3762/bjoc.8.113

• fast relaxation times for azobenzene-based photochromic molecular switches is still a challenge. This review focuses on the most recent achievements on azobenzene-based light-driven real-time information-transmitting systems. Besides, the main relationships between the structural features of the azo

• fatigue (Figure 25). Conclusion This review compiles very recently reported advances with regard to rapidly thermally isomerising azoderivatives, which are valuable candidates to be applied as fast information-transmitting photochromic switches. Two structural features should be present in the azobenzene

2-Allylphenyl glycosides as complementary building blocks for oligosaccharide and glycoconjugate synthesis

• Hemali D. Premathilake and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2012, 8, 597–605, doi:10.3762/bjoc.8.66

• ($ 35/100 g, Aldrich) in the presence of BF3·Et2O. For instance, acetylated AP β-D-glucopyranoside was obtained in 92% yield. Second, we anticipated that the same promoters used for O-pentenyl activation [30] can also activate the AP leaving group. However, since AP glycosides bear structural features

Synthesis and biological evaluation of nojirimycin- and pyrrolidine-based trehalase inhibitors

• Davide Bini,
• Francesca Cardona,
• Matilde Forcella,
• Camilla Parmeggiani,
• Paolo Parenti,
• Francesco Nicotra and
• Laura Cipolla

Beilstein J. Org. Chem. 2012, 8, 514–521, doi:10.3762/bjoc.8.58

• the insect glycosidase, while compounds 10, 14 and 16 behaved as inhibitors only of insect trehalase. Despite the fact that the activity was found in the micromolar range, these findings may help in elucidating the structural features of this class of enzymes of different origin, which are still

• , which ensures the synergistic interactions of an aminocyclitol or a nitrogen-containing heterocycle with the catalytic site, and of a sugar or cyclitol unit with the recognition site. However, this work may highlight relevant structural features of the catalytic site that can give access to specific

Synthesis of mesomeric betaine compounds with imidazolium-enolate structure

• Nina Gonsior,
• Fabian Mohr and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 390–397, doi:10.3762/bjoc.8.42

• and IR spectroscopy, as well as X-ray single-crystal analysis. The 1H NMR spectrum of 3 is depicted in Figure 1. The signals for all structural features were found, e.g., at 9.21 ppm, 7.81 ppm and 7.64 ppm, for the imidazolium protons, and in the range of 4.23–0.92 ppm for the butyl moiety

Fifty years of oxacalix[3]arenes: A review

• Kevin Cottet,
• Paula M. Marcos and
• Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

• [19]. As noted below, this extended aromatic surface is oriented perfectly for C60 inclusion [23]. 2 Conformational properties Oxacalix[3]arenes have received significant attention as receptors, mainly due to their structural features: A cavity formed by a 18-membered ring, only two basic

Access to pyrrolo-pyridines by gold-catalyzed hydroarylation of pyrroles tethered to terminal alkynes

• Elena Borsini,
• Gianluigi Broggini,
• Andrea Fasana,
• Chiara Baldassarri,
• Angelo M. Manzo and
• Alcide D. Perboni

Beilstein J. Org. Chem. 2011, 7, 1468–1474, doi:10.3762/bjoc.7.170

• pyrrolo-azepine derivatives, as already described in the literature by Beller and coworkers [18]. In order to shed light on the structural features determining the size of the newly formed ring, we thought it appropriate to extend this study further to N-propargyl-1-methylpyrrole-2-carboxamides bearing a

Meta-metallation of N,N-dimethylaniline: Contrasting direct sodium-mediated zincation with indirect sodiation-dialkylzinc co-complexation

• David R. Armstrong,
• Liam Balloch,
• Eva Hevia,
• Alan R. Kennedy,
• Robert E. Mulvey,
• Charles T. O'Hara and
• Stuart D. Robertson

Beilstein J. Org. Chem. 2011, 7, 1234–1248, doi:10.3762/bjoc.7.144

• mechanisms involved in the reactions of TMP-zincates, the solid-state structural features of an isolated decomposition product 5 ({(TMEDA)2Na}+{(t-Bu2Zn)2(µ-NMe2)}−) are also discussed, thus overall providing an illustrative example of the subtle, yet prodigious reactivity of the bimetallic base 1. Results