Development of the titanium–TADDOLate-catalyzed asymmetric fluorination of β-ketoesters

• Lukas Hintermann,
• Mauro Perseghini and
• Antonio Togni

Beilstein J. Org. Chem. 2011, 7, 1421–1435, doi:10.3762/bjoc.7.166

• catalysts [52] and small-molecule chiral amine catalysts were introduced and explored with great success [53][54][55][56]. Here we present the full range of observations on titanium-catalyzed fluorinations of β-ketoesters. The focus is on the development of the reaction and the study of factors influencing

Fine-tuning alkyne cycloadditions: Insights into photochemistry responsible for the double-strand DNA cleavage via structural perturbations in diaryl alkyne conjugates

• Wang-Yong Yang,
• Samantha A. Marrone,
• Nalisha Minors,
• Diego A. R. Zorio and
• Igor V. Alabugin

Beilstein J. Org. Chem. 2011, 7, 813–823, doi:10.3762/bjoc.7.93

• moiety cause the most efficient double-strand (ds) DNA cleavage known to date for a small molecule. In order to test the connection between the alkylating ability and the DNA-damaging properties of these compounds, we investigated the photoreactivity of three isomeric aryl–tetrafluoropyridinyl (TFP

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

C–C (alkynylation) vs C–O (ether) bond formation under Pd/C–Cu catalysis: synthesis and pharmacological evaluation of 4-alkynylthieno[2,3-d]pyrimidines

• Dhilli Rao Gorja,
• K. Shiva Kumar,
• K. Mukkanti and
• Manojit Pal

Beilstein J. Org. Chem. 2011, 7, 338–345, doi:10.3762/bjoc.7.44

• highly express these kinases [6]. In continuation of our research program into new drug discovery, we became interested in the generation of a small-molecule library A (Figure 1) based on thieno[2,3-d]pyrimidine for in-house pharmacological evaluation. Accordingly, we recently reported the synthesis of 4

Synthesis and self-assembly of 1-deoxyglucose derivatives as low molecular weight organogelators

• Guijun Wang,
• Hao Yang,
• Sherwin Cheuk and
• Sherman Coleman

Beilstein J. Org. Chem. 2011, 7, 234–242, doi:10.3762/bjoc.7.31

• matrices for enzymes, DNA, and drug delivery systems [22][23][24][25][26][27][28]. Glucose, in particular, is a versatile building block for the preparation of various small molecule gelators [30][31][32][33][34][35][36][37], as it is relatively easy to obtain substituted products by selective

Exceptionally small supramolecular hydrogelators based on aromatic–aromatic interactions

• Junfeng Shi,
• Yuan Gao,
• Zhimou Yang and
• Bing Xu

Beilstein J. Org. Chem. 2011, 7, 167–172, doi:10.3762/bjoc.7.23

• /bjoc.7.23 Abstract We report herein the use of an aromatic–aromatic interaction to produce small molecule hydrogelators that self-assemble in water and form molecular nanofibers in the resulting hydrogels. Among these hydrogelators, a hydrogelator (6) made from a phenylalanine and a cinnamoyl group

• low molecular weight hydrogelators [24][25][26][27][28][29]. Despite the intensive research and rapid advances in the design and synthesis of low molecular weight hydrogelators, the minimum structural requirement for a small molecule to act as a hydrogelator to form supramolecular hydrogels has been

Accuracy in determining interproton distances using Nuclear Overhauser Effect data from a flexible molecule

• Catharine R. Jones,
• Craig P. Butts and
• Jeremy N. Harvey

Beilstein J. Org. Chem. 2011, 7, 145–150, doi:10.3762/bjoc.7.20

• molecules when compared to their time-averaged computationally-derived distances in the alkyl chain of a small molecule – 4-propylaniline. These NOE-derived distances can thus be applied to modelling the populations (and hence energy differences) of the conformers, again with good accuracy when compared to

Palladium- and copper-mediated N-aryl bond formation reactions for the synthesis of biological active compounds

• Carolin Fischer and
• Burkhard Koenig

Beilstein J. Org. Chem. 2011, 7, 59–74, doi:10.3762/bjoc.7.10

• synthesis of complex molecules such as natural products or drugs is, in comparison to standard small-molecule N-arylation, not always straightforward and requires specially optimized conditions. Since amine- and amide-substituted aromatics and heteroaromatics are typical structures in medicinal chemistry

The catalytic performance of Ru–NHC alkylidene complexes: PCy₃ versus pyridine as the dissociating ligand

• Stefan Krehl,
• Diana Geißler,
• Sylvia Hauke,
• Oliver Kunz,
• Lucia Staude and
• Bernd Schmidt

Beilstein J. Org. Chem. 2010, 6, 1188–1198, doi:10.3762/bjoc.6.136

• ] catalyzed by a single site catalyst and initiated by organometallic transformations in situ, we became interested in the use of phosphine-free catalyst H. Unfortunately, only limited data is available concerning the catalytic efficiency of this catalyst in small molecule metathesis, in particular in

• Grubbs catalyst in various small molecule metathesis reactions. The activity of the mixed NHC-phosphine catalysts D and E appears to be similar in most applications. Some results hint at a somewhat faster reaction with benzylidene complex D, while E apparently performs slightly better in “slow

Physical organic chemistry

• John A. Murphy

Beilstein J. Org. Chem. 2010, 6, 1025–1025, doi:10.3762/bjoc.6.116

• kinetics of radical reactions. Applications to complex reactions in biology, polymer chemistry and electronic materials are ever more prevalent, and add to contributions in ‘small molecule’ chemistry. Novel experimental techniques combined with the revolution in computational chemistry give new impetus to

Pyridinium based amphiphilic hydrogelators as potential antibacterial agents

• Sayanti Brahmachari,
• Sisir Debnath,
• Sounak Dutta and
• Prasanta Kumar Das

Beilstein J. Org. Chem. 2010, 6, 859–868, doi:10.3762/bjoc.6.101

• varying the structure of its precursor molecules, (ii) have the ability for quick response to external stimuli, and (iii) are potentially biocompatible [12][23][24]. Thus, the huge range of applications of the hydrogels and the beneficial aspects of small molecule gelators including ease of preparation

• have synergistically led to a surge in the development of tailor-made LMWHs. The presence of an aromatic ring (for example, phenyl, naphthalene, N-fluorenyl-9-methoxycarbonyl (Fmoc), indole, pyridine) in small molecule gelator is known to have crucial influence in inducing self-aggregation towards

Synthesis of 5-(6-hydroxy-7H-purine-8-ylthio)- 2-(N-hydroxyformamido)pentanoic acid

• Yanmei Zhang,
• Greg Elliot,
• Adrian Saldanha,
• Igor Tsigelny,
• Dennis Carson and
• Wolf Wrasidlo

Beilstein J. Org. Chem. 2010, 6, 742–747, doi:10.3762/bjoc.6.93

• Yanmei Zhang Greg Elliot Adrian Saldanha Igor Tsigelny Dennis Carson Wolf Wrasidlo Moores Cancer Center, University of California San Diego, La Jolla, CA, 92093, USA 10.3762/bjoc.6.93 Abstract We have developed a synthetic route for the preparation of a hybrid bisubstrate small molecule based on

Kinetic studies and predictions on the hydrolysis and aminolysis of esters of 2-S-phosphorylacetates

• Milena Trmčić and
• David R. W. Hodgson

Beilstein J. Org. Chem. 2010, 6, 732–741, doi:10.3762/bjoc.6.87

• ; heterobifunctional cross-linker; hydrolysis; kinetics; thiophosphate; Introduction Heterobifunctional cross-linking agents are used widely in protein science for forming covalently-bonded protein-protein complexes [1] and protein-small molecule systems [2]. S-Alkylation and N-acylation processes are used together

• heterobifunctional cross-linking agents, particularly in the context of small-molecule synthetic applications. Results and Discussion 2-Bromoacetic acid esters 1 were prepared by allowing bromoacetyl bromide to react with the respective N-hydroxy species or nitrophenols in the presence of pyridine. After standard

Synthesis and binding studies of two new macrocyclic receptors for the stereoselective recognition of dipeptides

• Ana Maria Castilla,
• M. Morgan Conn and
• Pablo Ballester

Beilstein J. Org. Chem. 2010, 6, No. 5, doi:10.3762/bjoc.6.5

• differentiable functionality in a small molecule like 3. The sequential peptide coupling of two units of 4,4’-bis(alanyl)benzophenones 3a should lead to the construction of the designed macrocyclic bis-dipeptide receptor 1. Benzophenone 3a was converted into the carboxylic acid 8 by treatment with

Can we measure catalyst efficiency in asymmetric chemical reactions? A theoretical approach

• Shaimaa El-Fayyoumy,
• Matthew H. Todd and
• Christopher J. Richards

Beilstein J. Org. Chem. 2009, 5, No. 67, doi:10.3762/bjoc.5.67

• Anglia, Norwich, NR4 7TJ, UK 10.3762/bjoc.5.67 Abstract Small molecule asymmetric catalysts are often described as being “good” or “bad” but to date there has been no way of comparing catalyst efficiency quantitatively. We define a simple formula, Asymmetric Catalyst Efficiency (ACE), that allows for

• molecule catalysts with enzymes. We conclude that ACE is a useful descriptor for the comparison of diverse catalytic systems. It is also noteworthy that, despite the relatively short period of investigation into small molecule catalysts, they are competitive with enzymes with regards to this measure of

• that are widely used in laboratories around the world. Our focus here is less on the industrial use of small molecule catalysts, since there are other very specific requirements for the use of catalysts on a manufacturing scale; ours is a more academic consideration of what ‘efficiency’ means when