Reaction of oxiranes with cyclodextrins under high-energy ball-milling conditions

• László Jicsinszky,
• Federica Calsolaro,
• Katia Martina,
• Fabio Bucciol,
• Maela Manzoli and
• Giancarlo Cravotto

Beilstein J. Org. Chem. 2019, 15, 1448–1459, doi:10.3762/bjoc.15.145

• industrial methods cannot be expected to occur in the near future. In the case of CDPs, our main aims were to find an effective, reproducible and green method for the preparation of a uniform insoluble CDP and to study its complexation properties in order to discover the right direction for synthesis

Genomics-inspired discovery of massiliachelin, an agrochelin epimer from Massilia sp. NR 4-1

• Jan Diettrich,
• Hirokazu Kage and
• Markus Nett

Beilstein J. Org. Chem. 2019, 15, 1298–1303, doi:10.3762/bjoc.15.128

• the chemistry of the genus Massilia, in general. Because natural product-competent microorganisms typically synthesize multiple compounds [7], strain NR 4-1 appeared as a promising candidate to find further secondary metabolites. Further incentive for the chemical analysis of this bacterium came from

Steroid diversification by multicomponent reactions

• Leslie Reguera,
• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Daniel G. Rivera

Beilstein J. Org. Chem. 2019, 15, 1236–1256, doi:10.3762/bjoc.15.121

• chain. Albeit this reaction did not find later synthetic applications, it encompasses a nice example of the diversity of MCRs that can be applied to diversify steroidal skeletons. 2.2 Miscellaneous MCRs for steroid derivatization Despite isocyanide-based MCRs have been the main classes of multicomponent

Alkylation of lithiated dimethyl tartrate acetonide with unactivated alkyl halides and application to an asymmetric synthesis of the 2,8-dioxabicyclo[3.2.1]octane core of squalestatins/zaragozic acids

• Herman O. Sintim,
• Hamad H. Al Mamari,
• Hasanain A. A. Almohseni,
• Younes Fegheh-Hassanpour and
• David M. Hodgson

Beilstein J. Org. Chem. 2019, 15, 1194–1202, doi:10.3762/bjoc.15.116

• proposed chemistry (Scheme 2), we were pleased to find that initial studies with (R,R)-tartrate 7 and a 3-silyloxy-1-iodobutane 16 did generate alkylated tartrates (Scheme 5). Following Seebach’s protocol, with warming overnight to room temperature, gave a 50% yield (90% based on recovered iodide 16) of a

Insertion of [1.1.1]propellane into aromatic disulfides

• Robin M. Bär,
• Gregor Heinrich,
• Martin Nieger,
• Olaf Fuhr and
• Stefan Bräse

Beilstein J. Org. Chem. 2019, 15, 1172–1180, doi:10.3762/bjoc.15.114

• the first to use UV irradiation in this reaction, but did not report detailed conditions [28]. They used diacetyldithiol and 1 to obtain bisacetylthio[n]staffanes. To find feasible conditions for the insertion of 1 into disulfide bonds, a screening with irradiations of different wavelengths and other

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• preparation of heterocyclic compounds. This is mainly due to the need to find new efficient methods in order to save raw materials and work time. Without doubt, multicomponent approaches in chemical synthesis take the advantage of those two saving features. This economical profit is especially interesting for

Fabrication, characterization and adsorption properties of cucurbit[7]uril-functionalized polycaprolactone electrospun nanofibrous membranes

• Changzhong Chen,
• Fengbo Liu,
• Xiongzhi Zhang,
• Zhiyong Zhao and
• Simin Liu

Beilstein J. Org. Chem. 2019, 15, 992–999, doi:10.3762/bjoc.15.97

• through the electrospinning technique is on the way, in order to find a real application on the removal of organic wastes in water. Representative SEM images and the corresponding diameter distribution of the nanofibers: (a) neat PCL; (b) PCL/CB[7] (100:50); (c) PCL/CB[7] (100:100); (d) PCL/CB[7] (100:150

Halogen bonding and host–guest chemistry between N-alkylammonium resorcinarene halides, diiodoperfluorobutane and neutral guests

• Fangfang Pan,
• Mohadeseh Dashti,
• Michael R. Reynolds,
• Kari Rissanen,
• John F. Trant and
• Ngong Kodiah Beyeh

Beilstein J. Org. Chem. 2019, 15, 947–954, doi:10.3762/bjoc.15.91

• were positioned at the same level as the (HNH···Cl−)4 HB circle. The O···Cl− distances of 3.13(3) and 3.22(4) Å suggest OH···Cl− hydrogen bonds. Meanwhile, an OH···O hydrogen bond should also exist between the two water molecules with the O···O distance of 3.01(5) Å. It is surprising to find that the

Efficient synthesis of pyrazolopyridines containing a chromane backbone through domino reaction

• Razieh Navari,
• Saeed Balalaie,
• Saber Mehrparvar,
• Fatemeh Darvish,
• Frank Rominger,
• Fatima Hamdan and
• Sattar Mirzaie

Beilstein J. Org. Chem. 2019, 15, 874–880, doi:10.3762/bjoc.15.85

• phenylhydrazine [42][43]. Subjecting (arylhydrazono)methyl-4H-chromen-4-one (1a), benzylamine (2a), and malononitrile (3) in the presence of 40% triethylamine was stirred at room temperature in ethanol. Compound 4a was precipitated and filtered. After confirmation of the structure, we tried to find a suitable

Synthesis of a novel category of pseudo-peptides using an Ugi three-component reaction of levulinic acid as bifunctional substrate, amines, and amino acid-based isocyanides

• Maryam Khalesi,
• Azim Ziyaei Halimehjani and
• Jürgen Martens

Beilstein J. Org. Chem. 2019, 15, 852–857, doi:10.3762/bjoc.15.82

• isocyanides in the Ugi-4C-3CR, a mixture of diastereomers were obtained in approximately 1:1 ratio (see NMR spectra in Supporting Information File 1). Attempts to find a suitable procedure for separation of the diastereomers without losing the yield was not successful. In the case of 4a, one of the

Tuning the stability of alkoxyisopropyl protection groups

• Zehong Liang,
• Henna Koivikko,
• Mikko Oivanen and
• Petri Heinonen

Beilstein J. Org. Chem. 2019, 15, 746–751, doi:10.3762/bjoc.15.70

• . The vinyl ether hydrolysis has earlier shown to be even a subject of general acid catalysis [13][14]. It is useful to compare the stabilities of the acetal protections to those of the 4,4’-dimethoxytrityl protecting group used in oligonucleotide synthesis. Directly comparable data are hard to find

An efficient and concise access to 2-amino-4H-benzothiopyran-4-one derivatives

• Peng Li,
• Yongqi Wu,
• Tingting Zhang,
• Chen Ma,
• Ziyun Lin,
• Gang Li and
• Haihong Huang

Beilstein J. Org. Chem. 2019, 15, 703–709, doi:10.3762/bjoc.15.65

• representative amines including primary and secondary amines were then investigated in reactions with substrate 2a. We were pleased to find that various N-substituted 2-aminobenzothiopyranones 4e–i were afforded in moderate to good yields. In general, aliphatic amines NHR1R2 are stronger nucleophiles to furnish

Synthesis of the polyketide section of seragamide A and related cyclodepsipeptides via Negishi cross coupling

• Jan Hendrik Lang and
• Thomas Lindel

Beilstein J. Org. Chem. 2019, 15, 577–583, doi:10.3762/bjoc.15.53

• partial structures is driven by an interest in the chemistry of photoreactive amino acids and heterocycles that may find application in photoaffinity labelling. Knowing the binding of a natural product to a biological target at atomic resolution, as it is the case for the cyclodepsipeptide jasplakinolide

Synthesis and biological investigation of (+)-3-hydroxymethylartemisinin

• Toni Smeilus,
• Farnoush Mousavizadeh,
• Johannes Krieger,
• Xingzhao Tu,
• Marcel Kaiser and
• Athanassios Giannis

Beilstein J. Org. Chem. 2019, 15, 567–570, doi:10.3762/bjoc.15.51

• [8][9][10]. Recently, it was shown that artemisinin interacts with the mammalian protein gephyrin and by stabilizing it, it enhances GABAA receptor signaling resulting in in vivo conversion of pancreatic α-cells into functional β-like cells [11]. Therefore, this sesquiterpene lactone may also find an

Low-budget 3D-printed equipment for continuous flow reactions

• Jochen M. Neumaier,
• Amiera Madani,
• Thomas Klein and
• Thomas Ziegler

Beilstein J. Org. Chem. 2019, 15, 558–566, doi:10.3762/bjoc.15.50

• systems is the low chemical resistance of the used printing materials towards most organic solvents [11]. For the development and construction of our flow reactor we had to print and design numerous devices in order to find the most suitable parameters. All reactors were printed with a filament flow of

Back to the future: Why we need enzymology to build a synthetic metabolism of the future

• Tobias J. Erb

Beilstein J. Org. Chem. 2019, 15, 551–557, doi:10.3762/bjoc.15.49

• synthetic metabolic networks From above examples it becomes evident that for building completely novel pathways and/or complex reaction cascades, resources are required that provide synthetic biologists with the information to find individual enzymes for a given synthetic metabolic network. More than 116

• point to search for enzyme variants that possess a desired catalytic activity. While existing databases might provide a good resource to find the parts to reconstruct level 3 pathways, this task becomes more challenging in respect to level 4 and level 5 designs that require new-to-nature reactions. How

Selectivity in multiple multicomponent reactions: types and synthetic applications

• Ouldouz Ghashghaei,
• Francesca Seghetti and
• Rodolfo Lavilla

Beilstein J. Org. Chem. 2019, 15, 521–534, doi:10.3762/bjoc.15.46

• transformation would be feasible (Scheme 1). This review, which does not intend to be exhaustive, deals with the selectivity levels found in the literature and their impact on the synthetic outcome. In this way we may find different scenarios: i) completely unselective combinations leading to mixtures

Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines

• Andrejs Šišuļins,
• Jonas Bucevičius,
• Yu-Ting Tseng,
• Irina Novosjolova,
• Kaspars Traskovskis,
• Ērika Bizdēna,
• Huan-Tsung Chang,
• Sigitas Tumkevičius and
• Māris Turks

Beilstein J. Org. Chem. 2019, 15, 474–489, doi:10.3762/bjoc.15.41

• biocompatible, cell-permeable, not cytotoxic and do not influence cell proliferation. Thus, one can predict that the developed purine and 7-deazapurine derivatives possessing the novel substitution pattern may find their application also in cell labeling in the future besides the potential use as materials in

Thiol-free chemoenzymatic synthesis of β-ketosulfides

• Adrián A. Heredia,
• Martín G. López-Vidal,
• Marcela Kurina-Sanz,
• Fabricio R. Bisogno and
• Alicia B. Peñéñory

Beilstein J. Org. Chem. 2019, 15, 378–387, doi:10.3762/bjoc.15.34

• CAL-B. It is worth noting that this amount represents a ≈8 fold decrease of used enzyme as compared to the corresponding small scale reaction (Table 2, entry 8). After 24 h, we were delighted to find that no enolester was detected by TLC monitoring, and after extraction and silica gel column

Application of olefin metathesis in the synthesis of functionalized polyhedral oligomeric silsesquioxanes (POSS) and POSS-containing polymeric materials

• Patrycja Żak and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2019, 15, 310–332, doi:10.3762/bjoc.15.28

• reasonable to expect that olefin metathesis thanks to its advantages and charm will find numerous further applications in the synthesis of POSS-based materials. Cubic octasilsesquioxane. The scope and limitations of metathesis in transformations of vinyl-substituted siloxanes and silsesquioxanes. Olefin

Metal-free C–H mercaptalization of benzothiazoles and benzoxazoles using 1,3-propanedithiol as thiol source

• Yan Xiao,
• Bing Jing,
• Xiaoxia Liu,
• Hongyu Xue and
• Yajun Liu

Beilstein J. Org. Chem. 2019, 15, 279–284, doi:10.3762/bjoc.15.24

• substrate together with several aliphatic dithiols 2. Initially, benzothiazole was treated with 3.0 equiv of each aliphatic dithiol and 5.0 equiv of KOH in DMSO at 130 °C. After 12 h, we are delighted to find that 1a was predominantly converted to 2-mercaptobenzothiazole (3a). The investigation of the

First synthesis of cryptands with sucrose scaffold

• Patrycja Sokołowska,
• Michał Kowalski and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2019, 15, 210–217, doi:10.3762/bjoc.15.20

• and find many applications in, e.g., selective complexation of ionic and neutral species, medicinal chemistry (as drug carriers), and in the synthesis (as phase transfer catalysts). The complexing properties depend on several crucial parameters such as cavity size, type of heteroatoms involved in the

Adhesion, forces and the stability of interfaces

• Robin Guttmann,
• Johannes Hoja,
• Christoph Lechner,
• Reinhard J. Maurer and
• Alexander F. Sax

Beilstein J. Org. Chem. 2019, 15, 106–129, doi:10.3762/bjoc.15.12

Synthesis, biophysical properties, and RNase H activity of 6’-difluoro[4.3.0]bicyclo-DNA

• Sibylle Frei,
• Adam K. Katolik and
• Christian J. Leumann

Beilstein J. Org. Chem. 2019, 15, 79–88, doi:10.3762/bjoc.15.9

• indicate that the 6’-diF-bc4,3-DNA and the 6’F-bc4,3-DNA may find application in therapeutic gapmer oligonucleotides. Conclusion In this report, we presented the successful synthesis of the 6’-diF-bc4,3-T building block where the gem-difluorinated bicyclic unit was formed starting from a previously

Thermophilic phosphoribosyltransferases Thermus thermophilus HB27 in nucleotide synthesis

• Ilja V. Fateev,
• Ekaterina V. Sinitsina,
• Aiguzel U. Bikanasova,
• Maria A. Kostromina,
• Elena S. Tuzova,
• Larisa V. Esipova,
• Tatiana I. Muravyova,
• Alexei L. Kayushin,
• Irina D. Konstantinova and
• Roman S. Esipov

Beilstein J. Org. Chem. 2018, 14, 3098–3105, doi:10.3762/bjoc.14.289

• were verified by sequencing. The codone GGG→AGG substitution corresponding to amino-acid Arg27Gly replacement was found in the gene encoding the TthHPRT. The screening of available producer strains was performed to find strains, which produce target enzymes in soluble form. The resulting strains E

• phosphoribosyltransferase only [2]. Unfortunately, we did not find any product in reactions with compounds based on 1,2,4-triazole-3-carboxamide, which was also observed for E. сoli HPRT [15][16]. However, allopurinol and 8-azaguanine are substrates for TthHPRT, and 2-chloroadenine is a substrate for TthAPRT. For 2