Combining the Ugi-azide multicomponent reaction and rhodium(III)-catalyzed annulation for the synthesis of tetrazole-isoquinolone/pyridone hybrids

• Gerardo M. Ojeda,
• Prabhat Ranjan,
• Pavel Fedoseev,
• Lisandra Amable,
• Upendra K. Sharma,
• Daniel G. Rivera and
• Erik V. Van der Eycken

Beilstein J. Org. Chem. 2019, 15, 2447–2457, doi:10.3762/bjoc.15.237

• synthesis of isoquinolones using an N-methoxyamide as directing group for the ortho-position and alkynyl bromide to achieve the regioselective cyclization (Scheme 1B) [31]. In parallel, our group has developed Ru(II) and Rh(III)-catalyzed inter- and intramolecular annulations of aromatic rings with alkynes

• aldehydes were reacted in parallel with trimethylsilyl azide and tritylamine under microwave irradiation – followed by removal of the trityl group and acylation to afford the N-acylaminomethyltetrazoles 1a–s and 2a–l. The functionalized tetrazoles were obtained in moderate to excellent yields over three

Photochromic diarylethene ligands featuring 2-(imidazol-2-yl)pyridine coordination site and their iron(II) complexes

• Andrey G. Lvov,
• Max Mörtel,
• Anton V. Yadykov,
• Frank W. Heinemann,
• Valerii Z. Shirinian and
• Marat M. Khusniyarov

Beilstein J. Org. Chem. 2019, 15, 2428–2437, doi:10.3762/bjoc.15.235

• that bond. Two iron(II) centers are 8.057 Å apart in the dimer. The ligand 6 appears in the open-ring form and the parallel conformation [8], with the α-methyl groups pointing in similar directions. While still appearing in a distorted half-chair conformation, the phenyl substituent of the

• parallel conformation. Electronic structure of complexes 8 and 9 Microcrystalline samples of 8 and 9 were used for magnetic susceptibility measurements. Complex 8 shows a nearly constant χT product of 7.63 cm3·mol–1·K above 125 K (Figure 4). It increases gradually upon lowering the temperature, reaching a

Current understanding and biotechnological application of the bacterial diterpene synthase CotB2

• Ronja Driller,
• Daniel Garbe,
• Norbert Mehlmer,
• Monika Fuchs,
• Keren Raz,
• Dan Thomas Major,
• Thomas Brück and
• Bernhard Loll

Beilstein J. Org. Chem. 2019, 15, 2355–2368, doi:10.3762/bjoc.15.228

• synthase [47] and the sesquiterpene trichodiene synthase [48], but is in contrast to the parallel dimer as described for farnesyl diphosphate synthase [49]. Structurally, CotB2 is most closely related to the fungal monoterpene synthase aristolochene (PDB-ID 2OA6; [50]), and epi-isozizaene synthase (PDB-ID

Mono- and bithiophene-substituted diarylethene photoswitches with emissive open or closed forms

• A. Lennart Schleper,
• Mariano L. Bossi,
• Vladimir N. Belov and
• Stefan W. Hell

Beilstein J. Org. Chem. 2019, 15, 2344–2354, doi:10.3762/bjoc.15.227

• Information File 1), tetraester SyTh2 displayed six 1H NMR signals between 3.70 and 4.00 ppm, belonging to two inequivalent methyl ester groups and the methylene group of the parallel and antiparallel isomers. After the reaction, four of the six signals vanished, and only two methylene signals (two isomers

Perspective isomorphs – a new classification of molecular structures based on artistic and chemical concepts

• Jannis Neumann,
• Ansgar Schnurr and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2019, 15, 2319–2326, doi:10.3762/bjoc.15.224

• their physical (one-eyed) visual impression and projected the perception of parallel and converging lines and staggering forms onto the canvas [12]. Two aspects are significant here: First of all, items on a canvas appear radically in the way they are visually apprehensible (backsides and concealments

Tautomerism as primary signaling mechanism in metal sensing: the case of amide group

• Vera Deneva,
• Georgi Dobrikov,
• Aurelien Crochet,
• Daniela Nedeltcheva,
• Katharina M. Fromm and
• Liudmil Antonov

Beilstein J. Org. Chem. 2019, 15, 1898–1906, doi:10.3762/bjoc.15.185

• some cases to stabilization of the keto tautomer through formation of associates. This kind of aggregation reflects to the spectrum of 6 in acetonitrile. The formed aggregate (see Figure S1, Supporting Information File 1) has a H-type structure (also called “sandwich” type) [14] with parallel

Identification of optimal fluorescent probes for G-quadruplex nucleic acids through systematic exploration of mono- and distyryl dye libraries

• Xiao Xie,
• Michela Zuffo,
• Marie-Paule Teulade-Fichou and
• Anton Granzhan

Beilstein J. Org. Chem. 2019, 15, 1872–1889, doi:10.3762/bjoc.15.183

• and RNA structures The fluorimetric response of the dye library was investigated against a set of 14 diverse nucleic acid structures (Table 2), including ten G4-DNA structures of different topologies (parallel G4: c-kit2, 25CEB, c-kit87up, c-myc, c-src1; parallel dimer G4: c-myb; hybrid G4: 22AG, 46AG

• towards hybrid (22AG, 46AG) and antiparallel (HRAS) G4-DNA, whereas the second group (dyes 1s, 1u, 1v, 17a and 18a) shows fluorimetric selectivity for parallel G4-DNA forms (c-kit2, c-kit87up, c-myc). To verify the preferences of the dyes with respect to the conformation of the G4 analytes, we analysed

• and compounds selective for parallel G4s locating in the upper part. Interestingly, the loading vectors for parallel G4-RNA (NRAS and TERRA) fall in between those of parallel and hybrid/antiparallel DNA G4s, suggesting an impact of the ribose backbone on the interaction. As can be inferred from the

Halide metathesis in overdrive: mechanochemical synthesis of a heterometallic group 1 allyl complex

• Ross F. Koby,
• Nicholas R. Rightmire,
• Nathan D. Schley,
• Timothy P. Hanusa and
• William W. Brennessel

Beilstein J. Org. Chem. 2019, 15, 1856–1863, doi:10.3762/bjoc.15.181

• ] and the related DME and THF solvates [K(dme)A']∞ [21] and [K(thf)3/2A']∞ [18], respectively, [(C6H6)KA']∞ is a coordination polymer with potassium ions linked by bridging π-allyl ligands. The polymer takes the form of bent chains running parallel to the b axis (Figure 3). There is only one

A heteroditopic macrocycle as organocatalytic nanoreactor for pyrroloacridinone synthesis in water

• Piyali Sarkar,
• Sayan Sarkar and
• Pradyut Ghosh

Beilstein J. Org. Chem. 2019, 15, 1505–1514, doi:10.3762/bjoc.15.152

• aggregation tendency. Herein we have extensively explored a multifunctional macrocycle (BATA-MC), comprising bis-amide and tris-amine functionalities as H-bond donor/acceptor moieties, and parallel benzene moieties for aromatic π–π stacking interactions as an organocatalytic nanoreactor for organic

Diazocine-functionalized TATA platforms

• Roland Löw,
• Talina Rusch,
• Fynn Röhricht,
• Olaf Magnussen and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1485–1490, doi:10.3762/bjoc.15.150

• the configuration of the molecules on metal surfaces [15]. In 1 the OMe group is attached para and in 2 the methoxy group is meta with respect to the azo group. Model calculations predict that the Cphenyl–O bonds in the cis-isomers thus are parallel, and in the trans-isomers orthogonal to the surface

• (Figure 1). Previous investigations have shown that IRRAS (infrared absorption reflection spectroscopy) in combination with the surface selection rules (stretching mode orthogonal to the surface→high intensity, parallel to the surface→low intensity) is a suitable method to determine the configuration and

2,3-Dibutoxynaphthalene-based tetralactam macrocycles for recognizing precious metal chloride complexes

• Li-Li Wang,
• Yi-Kuan Tu,
• Huan Yao and
• Wei Jiang

Beilstein J. Org. Chem. 2019, 15, 1460–1467, doi:10.3762/bjoc.15.146

• pre-organized. In addition, there exist two conformations for both macrocycles 1 and 2 because the two 2,3-dibutoxynaphthalene moieties can be aligned either in parallel or antiparallel orientation (Scheme 1). These two conformations have different cavities defined by the parallel or antiparallel

• parallel orientation. Three of the four NH protons are directed into the cavity, and the fourth one flipped outward and forms a hydrogen bond with the oxygen atom of H2O (H···O distance: 1.97 Å). Two CH3CN molecules were trapped in the cavities by the amide groups through N–H···N hydrogen bonds (H···N

Introduction of an isoxazoline unit to the β-position of porphyrin via regioselective 1,3-dipolar cycloaddition reaction

• Xiujun Liu,
• Xiang Ma and
• Yaqing Feng

Beilstein J. Org. Chem. 2019, 15, 1434–1440, doi:10.3762/bjoc.15.143

• longer than the distance when MeOH coordinated to the Zn2+ ions [49]. This may attribute to the larger volume of the C6H4CO2Me group than MeOH when closing to the Zn2+ center. In the dimer structure, two planes defined by porphyrin macrocycles are parallel with a distance of 7.11 Å. The bulky substituent

Efficiency Eff_syn of complex syntheses as multicomponent reactions, its algorithm and calculations based on concrete criteria

• Heiner Eckert

Beilstein J. Org. Chem. 2019, 15, 1425–1433, doi:10.3762/bjoc.15.142

• always the case with MCRs. All such reactions are parallel reactions and do not have any sequential character with respect to each other, instead they are cumulative, whereby the parallel reaction groups have different numbers of individual reactions n. The yields yn then need to be weighted with these m

• values and the arithmetic mean yam calculated as shown in Equation 3. Algorithm If you insert Equation 1 in Equation 3, and then insert this in Equation 2, you will obtain the efficiency algorithm Equation 4. This has already been described in a general manner in [2][3]. The weighting of the parallel

• of 10 STMs) with which the synthesis can be started, as well as 12 other STMs. To have a better overview in this study (Scheme 1), reactions are ordered to a main reaction set including two MCRs (reactants A-T, TM U), connected with 4 parallel reaction sets including a 3CR (Scheme 2). Overall yield

Selenophene-containing heterotriacenes by a C–Se coupling/cyclization reaction

• Pierre-Olivier Schwartz,
• Sebastian Förtsch,
• Astrid Vogt,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2019, 15, 1379–1393, doi:10.3762/bjoc.15.138

• corresponding dibromobiselenophene and benzene sulfonyl sulfide as sulfur source (50% yield) [27]. In parallel, TMS-protected iodinated biselenophene 11 was subjected to selenourea, copper oxide nanoparticles, and potassium hydroxide in DMSO to isolate diselenolo[3,2-b:2’,3’-d]selenophene (DSS, 4) in 48% yield

• material 11 and dehalogenation was in parallel observed as competitive reaction pathway. Thus, mostly diiodobiselenophene 13 and 2,2’-biselenophene were isolated as main products. Independent reaction of deprotected diiodobiselenophene 13, which was alongside prepared from TMS-biselenophene 11 by

• formed dimers showed some differences: in DTT 1 the molecules overlap in a parallel orientation whereas in DST 3 an antiparallel orientation of the molecules in the dimer was found. The degree of overlap was determined to 73% and 64% for DTT 1 and DST 3, respectively. Less degree of overlap (43–53% and

Synthesis of dipolar molecular rotors as linkers for metal-organic frameworks

• Sebastian Hamer,
• Fynn Röhricht,
• Marius Jakoby,
• Ian A. Howard,
• Xianghui Zhang,
• Christian Näther and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1331–1338, doi:10.3762/bjoc.15.132

• compromise between the size and dipole moment of the rotor/linker has to be aimed at, and care has to be taken that the rotational barriers are as low as possible. Figure 1 shows the interaction of a pair of dipolar rotors with parallel axes at a distance of 10 Å, which is a typical distance of the linkers

• available in gram amounts for the synthesis of MOF or SURMOF structures with promising electric and optical properties. Interactions of a pair of dipolar rotors in different orientations. The axes of the rotors are parallel at a distance of 10 Å (terminal H atoms at the ethynyl units are in a plane and at

Bambusuril analogs based on alternating glycoluril and xylylene units

• Tomáš Lízal and
• Vladimír Šindelář

Beilstein J. Org. Chem. 2019, 15, 1268–1274, doi:10.3762/bjoc.15.124

• good agreement with the structure of the 1b-1 conformer calculated by DFT. The parallel glycoluril units are placed on one side of the plane defined by the xylylene moieties. The macrocycles form a layered structure stabilized by intermolecular hydrogen bonding interaction between the carbonyl oxygens

Unexpected polymorphism during a catalyzed mechanochemical Knoevenagel condensation

• Sebastian Haferkamp,
• Andrea Paul,
• Adam A. L. Michalchuk and
• Franziska Emmerling

Beilstein J. Org. Chem. 2019, 15, 1141–1148, doi:10.3762/bjoc.15.110

• data, they represent the underlying chemical or physical processes. In order to understand the results of PCA, both scores and loadings must be scrutinized in parallel. Whereas the scores contain information regarding the samples, the loadings provide information on the variables. High loading values

• clearly separated compounds, the Raman spectra suggest the parallel presence of 1a, m3a and t3a. Multivariate curve resolution (MCR) aims to extract information on the pure compounds [27]. In our case, the time series of Raman spectra may be considered as a superposition of all compounds present at a

Molecular recognition using tetralactam macrocycles with parallel aromatic sidewalls

• Dong-Hao Li and
• Bradley D. Smith

Beilstein J. Org. Chem. 2019, 15, 1086–1095, doi:10.3762/bjoc.15.105

• Dong-Hao Li Bradley D. Smith Department of Chemistry and Biochemistry, University of Notre Dame, 236 Nieuwland Science Hall, Notre Dame, Indiana 46556, United States 10.3762/bjoc.15.105 Abstract This review summarizes the supramolecular properties of tetralactam macrocycles that have parallel

• units connected by two parallel aromatic sidewalls and we have chosen to highlight them as one of the few classes of macrocyclic host molecules that have an amphiphilic cavity. As described below, the range of guest structures that bind within the cavity of this host family is quite broad. In the

• tetralactam A reported by the Leigh group in the mid 1990s [27][28]. The macrocycle has two parallel 1,4-phenylene sidewalls and when the two bridging units are 1,3-benzene dicarboxamides (X = CH) there is considerable conformational flexibility. For example, the empty macrocycle can easily adopt a

A chemically contiguous hapten approach for a heroin–fentanyl vaccine

• Yoshihiro Natori,
• Candy S. Hwang,
• Lucy Lin,
• Lauren C. Smith,
• Bin Zhou and
• Kim D. Janda

Beilstein J. Org. Chem. 2019, 15, 1020–1031, doi:10.3762/bjoc.15.100

• obtain an aldehyde that could then be used in a reductive amination. Beginning with the commercially available 4-(4-bromophenyl)butanoic acid, an alkene was installed with a Suzuki reaction, which in turn underwent ozonolysis to give 21, shown in Scheme 4. In parallel, a commercially available piperidine

• the same linker as HF-4, its lengthy epitope actually required a different, but parallel synthetic strategy. The same commercially available piperidine used to obtain 24 was instead acylated with phthaloyl-protected aminopropanoyl chloride, deprotected, and reductively aminated with 21 to give 33

• , 86%; c) H2NNH2, EtOH, 89%; d) 1-phenethylpiperidin-4-one, NaBH(OAC)3, AcOH, 0 °C to rt, 92%. General outline of HF-5, HF-8, HF-9 synthesis from fentanyl intermediates 28 and 46, and heroin intermediates 16, and 36. Parallel synthesis of fentanyl domains 25 and 34, for HF-4 and HF-6, respectively

New terpenoids from the fermentation broth of the edible mushroom Cyclocybe aegerita

• Frank Surup,
• Florian Hennicke,
• Nadine Sella,
• Maria Stroot,
• Steffen Bernecker,
• Sebastian Pfütze,
• Marc Stadler and
• Martin Rühl

Beilstein J. Org. Chem. 2019, 15, 1000–1007, doi:10.3762/bjoc.15.98

• verify this assumption. Conclusion We identified bovistol A (1) as the main metabolite of C. aegerita in cultures. In parallel, we isolated its new disesquiterpenoid derivatives bovistol B (2) and C (3) as well as the new protoilludane pasteurestin C (4). By a qPCR approach, we were able to link 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

• chromatography without degradation. The compatibility of these protecting groups in parallel use with benzoyl and silyl groups was verified. The stabilities of the different alkoxy acetal protecting groups were compared by following the kinetics of their hydrolysis at 25.0 °C in buffered solutions through an

Design of indole- and MCR-based macrocycles as p53-MDM2 antagonists

• Constantinos G. Neochoritis,
• Maryam Kazemi Miraki,
• Eman M. M. Abdelraheem,
• Ewa Surmiak,
• Tryfon Zarganes-Tzitzikas,
• Beata Łabuzek,
• Tad A. Holak and
• Alexander Dömling

Beilstein J. Org. Chem. 2019, 15, 513–520, doi:10.3762/bjoc.15.45

• bear a heteroatom in the 4-position as oxygen or sulfur (Y = O, S, Scheme 2) were employed in order to enhance the diversity of our macrocycles [4]. Thus, in a parallel way, we readily synthesized 12 different amino acids which were subsequently subjected to the Ugi macrocyclization. After quite some

Silanediol versus chlorosilanol: hydrolyses and hydrogen-bonding catalyses with fenchole-based silanes

• Falco Fox,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2019, 15, 167–186, doi:10.3762/bjoc.15.17

• ). For 8ax the OH group is parallel situated to the biaryl axis. For 8eq the OH group is orthogonal oriented to the biaryl axis. The fenchyl groups are abbreviated with (*) for more clarity. Computed hydrolyses of BIFOXSiCl2 (7) to BIFOXSiCl(OH) 8ax and BIFOXSiCl(OH) 8eq and subsequent computed

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

• stabilization of parallel alkane chains, as well as the stabilization of aromatic molecules adsorbed to graphene or carbon nanotubes. Furthermore, we found that the stabilization energy of an adsorbent and several small adsorbate molecules increases when the latter are in close contact with each other. This

• range, but it allows to understand the transferability of group contributions of, for example, pairs of CH2 in two parallel aligned alkane chains. For the interaction of atoms or small molecules with extended metal surfaces, the concept of near-sightedness of dispersion does not apply, because the

Lectins of Mycobacterium tuberculosis – rarely studied proteins

• Katharina Kolbe,
• Sri Kumar Veleti,
• Norbert Reiling and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2019, 15, 1–15, doi:10.3762/bjoc.15.1

• membrane is surrounded by a peptidoglycan layer (PG) consisting of multiple, parallel glycan chains of alternating (1→4)-linked subunits of N-acetyl-β-D-glucosamine and N-acetyl- or N-glycolyl-β-D-muramic acid, crosslinked via short conserved oligopeptide stems [44][45]. The PG is covalently attached to