Volatiles from the tropical ascomycete Daldinia clavata (Hypoxylaceae, Xylariales)

• Tao Wang,
• Kathrin I. Mohr,
• Marc Stadler and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2018, 14, 135–147, doi:10.3762/bjoc.14.9

• /bjoc.14.9 Abstract The volatiles from the fungus Daldinia clavata were collected by use of a closed-loop stripping apparatus and analysed by GC–MS. A few compounds were readily identified by comparison of measured to library mass spectra and of retention indices to published data, while for other

Position-dependent impact of hexafluoroleucine and trifluoroisoleucine on protease digestion

• Susanne Huhmann,
• Anne-Katrin Stegemann,
• Kristin Folmert,
• Damian Klemczak,
• Johann Moschner,
• Michelle Kube and
• Beate Koksch

Beilstein J. Org. Chem. 2017, 13, 2869–2882, doi:10.3762/bjoc.13.279

• was designed to comprise substrate specificities of different proteases. Therefore, leucine, isoleucine, and their side-chain fluorinated variants were site-specifically incorporated at different positions of this peptide resulting in a library of 13 distinct peptides. The stability of these peptides

• substituted individually with either TfIle or HfLeu (Figure 1a). Ile and Leu variants were also included in this study as non-fluorinated controls. This led to a library of 12 FA variants (Figure 1b). Leu and Ile are larger and more hydrophobic than Ala. The fluorinated amino acids are even larger and more

• ’, the introduction of three fluorine atoms into Ile slows down proteolysis, although both peptides are completely digested after 24 h. For almost all peptides of our library, we observed the expected cleavage pattern with Phe in the P1 position (Figure 5, see Supporting Information File 1, Table S5

The use of 4,4,4-trifluorothreonine to stabilize extended peptide structures and mimic β-strands

• Yaochun Xu,
• Isabelle Correia,
• Tap Ha-Duong,
• Nadjib Kihal,
• Jean-Louis Soulier,
• Julia Kaffy,
• Benoît Crousse,
• Olivier Lequin and
• Sandrine Ongeri

Beilstein J. Org. Chem. 2017, 13, 2842–2853, doi:10.3762/bjoc.13.276

• -Hα coupling constant is also a valuable descriptor of peptide backbone conformations [32]. The coupling constants in all pentapeptides (Table 3) exhibit large values (6.8–9.2 Hz range), that are systematically higher than average values found in the coil library (6.1, 7.0, and 7.5 Hz for Ala, Leu and

One-pot syntheses of blue-luminescent 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones by T3P^® activation of 3-arylpropiolic acids

• Melanie Denißen,
• Alexander Kraus,
• Guido J. Reiss and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2017, 13, 2340–2351, doi:10.3762/bjoc.13.231

• can be detected and monitored by absorption and emission spectroscopy. Furthermore, the investigation of a substance library of various 2,3- and 1,8-naphthalene imides has shown that the electronic nature of the ground and the excited state is decisively influenced by variation of the substitution

• -dihydro-1H-benzo[f]isoindolyl moiety in 6 are absolutely planar. Photophysical properties The pseudo three-component synthesis of 1H-benzo[f]isoindole-1,3(2H)-diones 4 furnishes a substance library with electronically diverse substitution patterns and already upon eyesight several derivatives are

Preactivation-based chemoselective glycosylations: A powerful strategy for oligosaccharide assembly

• Weizhun Yang,
• Bo Yang,
• Sherif Ramadan and
• Xuefei Huang

Beilstein J. Org. Chem. 2017, 13, 2094–2114, doi:10.3762/bjoc.13.207

• , producing trisaccharide selenoglycoside 11 in 90% yield (Scheme 4). Following the same reaction protocol trisaccharide 11 and glycosylated acceptor 9 lead to tetrasaccharide 12, which was further extended to heptasaccharide 13. This method has also been applied to generate a library of phytoalexin elicitor

• 4-(benzenesulfinyl)morpholine (BSM)/Tf2O [53]. The combination of BSP/Tf2O [19][49] has been utilized as the promoter for iterative oligosaccharide synthesis including oligoglucosamine library [20], oligomannan [54] and Lewisa trisaccharide [55]. During their synthesis, van der Marel and co-workers

• synthesis of libraries of oligosaccharides by divergently combining building blocks. An example of this is the preparation of a library of heparan sulfate oligosaccharides (Figure 8) [74]. Alternating use of disaccharide building blocks 127 and 128 in preactivation-based one-pot glycosylation led to a panel

Mechanically induced oxidation of alcohols to aldehydes and ketones in ambient air: Revisiting TEMPO-assisted oxidations

• Andrea Porcheddu,
• Evelina Colacino,
• Giancarlo Cravotto,
• Francesco Delogu and
• Lidia De Luca

Beilstein J. Org. Chem. 2017, 13, 2049–2055, doi:10.3762/bjoc.13.202

• observed. Conclusion We have developed a TEMPO-based oxidative procedure for the air oxidation of primary and secondary benzyl alcohols to the corresponding aldehydes and ketones under ball milling conditions. A library of common alcohols was efficiently converted into carbonyl compounds with no trace of

Intramolecular glycosylation

• Xiao G. Jia and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

• of the relative positioning of the reaction counterparts. This peptide-based templating was extended to the synthesis of a small library of disaccharides. Non-symmetrical and other tethers Non-symmetrical templates have also been developed with a general idea of achieving differentially cleavable

One-pot multistep mechanochemical synthesis of fluorinated pyrazolones

• Joseph L. Howard,
• William Nicholson,
• Yerbol Sagatov and
• Duncan L. Browne

Beilstein J. Org. Chem. 2017, 13, 1950–1956, doi:10.3762/bjoc.13.189

• processes to such a system. After careful consideration of physical form and additive compatibility the final protocol has been successfully applied to the preparation of a small library of 12 difluorinated pyrazolones, several of which are hitherto unreported. Factors to be considered regarding the

Enzymatic synthesis of glycosides: from natural O- and N-glycosides to rare C- and S-glycosides

• Jihen Ati,
• Pierre Lafite and
• Richard Daniellou

Beilstein J. Org. Chem. 2017, 13, 1857–1865, doi:10.3762/bjoc.13.180

• acceptors (Table 1). Still, as demonstrated by the CAZY database, the glycoscientists have nowadays access to a large (and increasing) library of GTs and GHs, and in a near future, they will be able to perform most reactions enzymatically. In addition, the access to large quantities of inexpensive

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

• accompanied by macroscopic or ultrastructural signs of nerve destruction and hypoesthesia. Subsequent experiments revealed that mycolactone exposure caused hyperpolarization of neurons derived from PC12 cells that was mediated by the TRAAK potassium channel. Finally, screening of a siRNA library targeting

Molecular recognition of N-acetyltryptophan enantiomers by β-cyclodextrin

• Spyros D. Chatziefthimiou,
• Mario Inclán,
• Petros Giastas,
• Athanasios Papakyriakou,
• Konstantina Yannakopoulou and
• Irene M. Mavridis

Beilstein J. Org. Chem. 2017, 13, 1572–1582, doi:10.3762/bjoc.13.157

• carried out on a 500 MHz Bruker Avance instrument at 300 K using a BBI probe, the library pulse sequences and 300 ms mixing time for the 2D ROESY runs. The compounds were dissolved in unbuffered D2O. The data was processed with Topspin. X-ray crystallography Crystallisation of β-CD–L-NAcTrp. In an aqueous

Grip on complexity in chemical reaction networks

• Albert S. Y. Wong and
• Wilhelm T. S. Huck

Beilstein J. Org. Chem. 2017, 13, 1486–1497, doi:10.3762/bjoc.13.147

• of a bilayer network composed of the mechanical action of a temperature-responsive gel coupled with various exothermic reactions. Reprinted with permission from [34], copyright 2012 Nature Publishing Group. (b) Small dynamic combinatorial library made from dithiol building blocks. Adapted with

Biomimetic molecular design tools that learn, evolve, and adapt

• David A Winkler

Beilstein J. Org. Chem. 2017, 13, 1288–1302, doi:10.3762/bjoc.13.125

• characterization facility at CSIRO Manufacturing in Melbourne Australia. This can generate and test hundreds of polymers, nanomaterials, catalysts, or metal organic frameworks in a day. Clearly, certain types of chemistries (benzodiazepines, click reactions, etc.) are amenable to large chemical library synthesis

Aqueous semisynthesis of C-glycoside glycamines from agarose

• Juliana C. Cunico Dallagnol,
• Alexandre Orsato,
• Diogo R. B. Ducatti,
• Miguel D. Noseda,
• Maria Eugênia R. Duarte and
• Alan G. Gonçalves

Beilstein J. Org. Chem. 2017, 13, 1222–1229, doi:10.3762/bjoc.13.121

• on neighborhood chemical shifts (note H-1a, H-1b, H-2 and H-3, Figure 1). Even the coupling constant values (J) were slightly influenced (JH2-H3 = 3.6 Hz in 3 and 7; JH2-H3 = 3.9 Hz in 8, Table 2). The aforementioned might translate small conformational changes. In order to extend our library, and to

Towards open-ended evolution in self-replicating molecular systems

• Herman Duim and
• Sijbren Otto

Beilstein J. Org. Chem. 2017, 13, 1189–1203, doi:10.3762/bjoc.13.118

• amplification and selection processes using a technique called systematic evolution of ligands by exponential enrichment, or SELEX. In SELEX, a library of DNA and RNA sequences is exposed to a certain target. In multiple selection rounds the binding species are selected and amplified, while the non-binding DNA

• -replicating system involving peptides capable of diversification using a systems chemistry approach [52]. Following the discovery of an exponentially growing self-replicating system [53], we used two building blocks, 1 and 2, to form a dynamic combinational library (DCL) of self-replicating molecules. These

An eco-compatible strategy for the diversity-oriented synthesis of macrocycles exploiting carbohydrate-derived building blocks

• Sushil K. Maurya and
• Rohit Rana

Beilstein J. Org. Chem. 2017, 13, 1106–1118, doi:10.3762/bjoc.13.110

• , Himachal Pradesh, 176 061, India 10.3762/bjoc.13.110 Abstract An efficient, eco-compatible diversity-oriented synthesis (DOS) approach for the generation of library of sugar embedded macrocyclic compounds with various ring size containing 1,2,3-triazole has been developed. This concise strategy involves

• potential of the new eco-compatible approach for the macrocyclic library generation. Keywords: carbohydrate; click chemistry; diversity-oriented synthesis; macrocycles; ring-closing metathesis; Introduction Macrocycles offer very complex molecular architectures with a diverse range of ring sizes decorated

• macrocycles are rare and usually produce only compounds with a similar skeleton [20][33]. However, to achieve a higher hit rate against a broader range of targets libraries of diverse collections of macrocycles are desired [54]. The various diversity elements of a given library should include the molecular

Automating multistep flow synthesis: approach and challenges in integrating chemistry, machines and logic

• Chinmay A. Shukla and
• Amol A. Kulkarni

Beilstein J. Org. Chem. 2017, 13, 960–987, doi:10.3762/bjoc.13.97

• ][16][17][18][19][20][21][22][23][24]. Several integrated protocols have been developed for generating a library of compounds [12][25][26][27]. In-line separators like scavenging columns [22][25][26][27][28], liquid–liquid extractors (based on gravity or membrane) [3][23][29], distillation [30], etc

• reactants, intermediates or products at the outlet of the reactors or separators. It may also involve in-line measurement of other process parameters (often not shown in the literature) like temperature, pressure, pH, level, etc. [33]. Such automation is useful for screening a large library of potential

• multistep flow synthesis needs to be carried out to enhance the productivity and reliability of a synthesis protocol. Automation in lab-scale environment: Automation can significantly improve the productivity of lab scale experiments and also aid speeding up the synthesis of a library of compounds and drug

A practical and efficient approach to imidazo[1,2-a]pyridine-fused isoquinolines through the post-GBB transformation strategy

• Taofeng Shao,
• Zhiming Gong,
• Tianyi Su,
• Wei Hao and
• Chao Che

Beilstein J. Org. Chem. 2017, 13, 817–824, doi:10.3762/bjoc.13.82

• attracted broad attention in the field of organic synthesis [40][41][42]. In order to expand the structural diversity of GBB products, further investigation of GBB-based synthetic strategies remains highly desirable. In continuation of our research on the development of MCR strategies for the rapid library

• hand, we then set out to explore the reaction scope for the library generation of structurally diverse imidazo[1,2-a]pyridine-fused isoquinolines and the results are collected in Table 2. Initially, several GBB adducts 4 were synthesized through GBB reaction of amidines 1, substituted 2

• good yields through the GBB multicomponent reaction/Au-catalyzed cyclization strategy. The described method provides a new tool for a rapid compound library generation from readily accessible starting materials. Further, the protocol tolerates a broad substrate scope, which will make it attractive for

DMAP-assisted sulfonylation as an efficient step for the methylation of primary amine motifs on solid support

• Johnny N. Naoum,
• Koushik Chandra,
• Dorit Shemesh,
• R. Benny Gerber,
• Chaim Gilon and
• Mattan Hurevich

Beilstein J. Org. Chem. 2017, 13, 806–816, doi:10.3762/bjoc.13.81

• procedure on solid support [3][24][25]. These improvements enabled, for the first time, the synthesis of a combinatorial library of all possible N-methylated analogues of a given sequence [26]. These strategies have been used over two decades as standard procedures for N-methylations of linear and cyclic

A chemoselective and continuous synthesis of m-sulfamoylbenzamide analogues

• Arno Verlee,
• Thomas Heugebaert,
• Tom van der Meer,
• Pavel I. Kerchev,
• Frank Van Breusegem and
• Christian V. Stevens

Beilstein J. Org. Chem. 2017, 13, 303–312, doi:10.3762/bjoc.13.33

• infra). Synthesis of a small library in continuous flow The use of flow chemistry facilitated greatly the synthesis of an extended library of compounds. Different m-sulfamoylbenzamide analogues were synthesized in continuous flow. From Table 4, 15 analogues were produced on a larger scale to exemplify

• amines, a decrease in substrate concentration was essential to selectively obtain amides over sulfonamides. It was shown that the procedure can easily be used for the synthesis of a compound library suitable for initial screening; and that the optimized synthetic conditions are directly transferrable

• chemoselectivity with azepane as (F2). Screening results of the different conditions for the best chemoselectivity with azepane and aniline as (F2) and (F3), respectively. Chemoselectivity (%) of the medium-throughput synthesis in continuous flow. Library of 15 m-sulfamoylbenzamide analogues synthesized in

Versatile synthesis of the signaling peptide glorin

• Robert Barnett,
• Daniel Raszkowski,
• Thomas Winckler and
• Pierre Stallforth

Beilstein J. Org. Chem. 2017, 13, 247–250, doi:10.3762/bjoc.13.27

• derivatizations. Glorin, as well as the hydrolytically more stable derivative glorinamide, were shown to display comparable glorin-induced gene expression in Polysphondylium pallidum. In future this synthesis will facilitate the construction of a library of glorin derivatives for a detailed structure–activity

Continuous-flow synthesis of highly functionalized imidazo-oxadiazoles facilitated by microfluidic extraction

• Ananda Herath and
• Nicholas D. P. Cosford

Beilstein J. Org. Chem. 2017, 13, 239–246, doi:10.3762/bjoc.13.26

• , three-microreactor method for the highly efficient preparation of a diverse library of imidazo-oxadiazole derivatives. Moreover, this continuous-flow method was successfully combined with a single-step liquid–liquid microextraction unit to remove high boiling point polar solvents and impurities. Results

• less attractive during scale-up due to the difficulty of removal of these solvents during purification. Consequently the current method is limited to small scale library synthesis. Therefore, our next goal was to convert this microfluidic procedure to a sequence that would deliver compounds on a larger

A new class of organogelators based on triphenylmethyl derivatives of primary alcohols: hydrophobic interactions alone can mediate gelation

• Wangkhem P. Singh and
• Rajkumar S. Singh

Beilstein J. Org. Chem. 2017, 13, 138–149, doi:10.3762/bjoc.13.17

• commonly used protecting group for primary alcohols as a gelling structural component in the design of molecular gelators. We synthesized a small library of triphenylmethyl derivatives of simple primary alcohols and studied their gelation properties in different solvents. Gelation efficiency for some of

• geometry (unlike the planar geometry of say anthracene, pyrene, etc.), π–π stacking will be favoured only between benzene units of different trityl groups. A small library of triphenylmethyl derivatives was synthesized from the corresponding primary alcohols employing a single step reaction and detailed

• gelation studies carried out. Remarkably, we found that some of these triphenylmethyl derivatives can act as efficient gelators of some polar solvents thereby validating our approach. Results and Discussion Synthesis We synthesized a small library of triphenylmethyl derivatives of easily available simple

Synthesis of structurally diverse 3,4-dihydropyrimidin-2(1H)-ones via sequential Biginelli and Passerini reactions

• Andreas C. Boukis,
• Baptiste Monney and
• Michael A. R. Meier

Beilstein J. Org. Chem. 2017, 13, 54–62, doi:10.3762/bjoc.13.7

• in combination with the Biginelli reaction by Brodsky et al. [35]. In this work, five Biginelli acids were synthesized in 33–83% yields and utilized in a Ugi reaction for the synthesis of six DHMP amides with 21–63% yields. In a similar reaction strategy, Wipf et al. synthesized a library of twelve

Iodination of carbohydrate-derived 1,2-oxazines to enantiopure 5-iodo-3,6-dihydro-2H-1,2-oxazines and subsequent palladium-catalyzed cross-coupling reactions

• Michal Medvecký,
• Igor Linder,
• Luise Schefzig,
• Hans-Ulrich Reissig and
• Reinhold Zimmer

Beilstein J. Org. Chem. 2016, 12, 2898–2905, doi:10.3762/bjoc.12.289

• allow subsequent C–C functionalization at the C-5 position employing various palladium-catalyzed cross-coupling reactions thus expanding the library of available enantiopure 3,6-dihydro-2H-1,2-oxazines. Results and Discussion Numerous procedures exist for the synthesis of β-iodo enol ethers [27