Conformational preferences of α-fluoroketones may influence their reactivity

• Graham Pattison

Beilstein J. Org. Chem. 2017, 13, 2915–2921, doi:10.3762/bjoc.13.284

• ][13][14][15]. IR spectroscopy was used to show an increased preference for a cis (0° dihedral angle) compared to a gauche (150°) conformation in α-fluoroacetophenone compared to α-chloroacetophenone [16]. This has significant implications for the orbital overlap in these systems as it would be

Pyrene–nucleobase conjugates: synthesis, oligonucleotide binding and confocal bioimaging studies

• Artur Jabłoński,
• Yannic Fritz,
• Hans-Achim Wagenknecht,
• Rafał Czerwieniec,
• Tytus Bernaś,
• Damian Trzybiński,
• Krzysztof Woźniak and
• Konrad Kowalski

Beilstein J. Org. Chem. 2017, 13, 2521–2534, doi:10.3762/bjoc.13.249

• proceeded smoothly to yield 5 as colorless solid in 85% yield (Scheme 1). All pyrenyl derivatives 1–5 were characterized by 1H NMR, 13C NMR, and IR spectroscopy, mass spectrometry and elemental analysis, and the analytical data confirmed the proposed structures. Furthermore the molecular structure of

Synthesis, effect of substituents on the regiochemistry and equilibrium studies of tetrazolo[1,5-a]pyrimidine/2-azidopyrimidines

• Elisandra Scapin,
• Paulo R. S. Salbego,
• Caroline R. Bender,
• Alexandre R. Meyer,
• Anderson B. Pagliari,
• Tainára Orlando,
• Geórgia C. Zimmer,
• Clarissa P. Frizzo,
• Helio G. Bonacorso,
• Nilo Zanatta and
• Marcos A. P. Martins

Beilstein J. Org. Chem. 2017, 13, 2396–2407, doi:10.3762/bjoc.13.237

• , resulting in a 2-azidopyrimidine compound. The structures of compounds 7a,b and 7f were also confirmed by IR spectroscopy in the solid state. The FTIR spectrum, recorded using a KBr pellet, exhibited a strong absorption band corresponding to the azido group [47] at 2140 cm−1 and 2160 cm−1, thus

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

• spectroscopy. For verification of the structure by NMR and IR spectroscopy, the hydrolysis was performed on a preparative scale with ammonium chloride in a mixture of water and acetone. After complete removal of water, the IR spectrum shows the characteristic OH-stretching vibrations of the free carboxylic

Is the tungsten(IV) complex (NEt₄)₂[WO(mnt)₂] a functional analogue of acetylene hydratase?

• Matthias Schreyer and
• Lukas Hintermann

Beilstein J. Org. Chem. 2017, 13, 2332–2339, doi:10.3762/bjoc.13.230

• 13C NMR spectroscopy, IR spectroscopy, and by its dark purple color. A diagnostic analytical property in solution is δC of C-2/3 in the mnt ligand (δC = 140.4 ppm for 1) that depends on changes in the oxidation state, particularly oxidation to [WO2(mnt)2]2− (δC = 123.3 ppm). In a preliminary

Structural diversity in the host–guest complexes of the antifolate pemetrexed with native cyclodextrins: gas phase, solution and solid state studies

• Magdalena Ceborska,
• Magdalena Zimnicka,
• Aneta Aniela Kowalska,
• Kajetan Dąbrowa and
• Barbara Repeć

Beilstein J. Org. Chem. 2017, 13, 2252–2263, doi:10.3762/bjoc.13.222

• methods – FTIR–ATR and Raman were used for describing the way of PTX-CD interactions. The IR spectroscopy in the region characteristic for δ-HOH bending of water molecules attached to CDs (1600–1700 cm−1) is usually employed for tracking of the inclusion complex formation, however, Raman spectra of this

p-tert-Butylthiacalix[4]arenes functionalized by N-(4’-nitrophenyl)acetamide and N,N-diethylacetamide fragments: synthesis and binding of anionic guests

• Alena A. Vavilova and
• Ivan I. Stoikov

Beilstein J. Org. Chem. 2017, 13, 1940–1949, doi:10.3762/bjoc.13.188

• conformation was obtained with 10% yield (Scheme 1). 1Н, 13С, 2D NOESY NMR, IR spectroscopy, mass spectrometry (MALDI–TOF) confirmed the macrocycle 3 structure. The elemental analysis gives us the composition of 3. In contrast to the 1H NMR spectrum of 1,3-disubstituted thiacalix[4]arene 2 [42], the signals of

Solvent-free sonochemistry: Sonochemical organic synthesis in the absence of a liquid medium

• Deborah E. Crawford

Beilstein J. Org. Chem. 2017, 13, 1850–1856, doi:10.3762/bjoc.13.179

• ). Powder X-ray diffraction (PXRD) analysis shows that the powder patterns of both the sonochemical product and the solution product are the same and IR spectroscopy confirmed that an imine bond was present in the product, with no indication of an aldehyde functionality being present (see Supporting

Mechanochemical N-alkylation of imides

• Anamarija Briš,
• Mateja Đud and
• Davor Margetić

Beilstein J. Org. Chem. 2017, 13, 1745–1752, doi:10.3762/bjoc.13.169

• organic solvents. Ex situ IR spectroscopy (ATR) of milling of imides 11–17 with K2CO3 was used for monitoring the reaction progress, which showed for instance, that potassium phthalimide [29] was formed after one hour of grinding (Figure 2). This salt was, without isolation, subjected to further milling

• conditions for various organic reactions. Products of alkylation of imides 11–17. Ex situ IR spectroscopy of the reaction of 12 and benzyl bromide in the ball mill: a) phthalimide 12; b) first step: phthalimide + K2CO3, 1 h milling; c) second step: addition of benzyl bromide, LAG DMF and further 1 h milling

Block copolymers from ionic liquids for the preparation of thin carbonaceous shells

• Sadaf Hanif,
• Bernd Oschmann,
• Dmitri Spetter,
• Muhammad Nawaz Tahir,
• Wolfgang Tremel and
• Rudolf Zentel

Beilstein J. Org. Chem. 2017, 13, 1693–1701, doi:10.3762/bjoc.13.163

• at 45 °C. The broad signal which is typical for the NAS block can be observed at 2.8 ppm as shown in Figure 3. Another proof for the formation of a reactive ester block was given by IR spectroscopy. A new band can be observed at 1732 cm−1 and is assigned to the carbonyl group of the reactive ester

• successful conversion of the reactive ester to the corresponding amide. The NAS shift at 2.8 ppm vanished, while new shifts appeared at 6.5 ppm and in the range of 8.5–8.8 ppm corresponding to the aromatic ring of dopamine. This can be further confirmed by IR spectroscopy (Figure S6, Supporting Information

Synthesis and metal binding properties of N-alkylcarboxyspiropyrans

• Alexis Perry and
• Christina J. Kousseff

Beilstein J. Org. Chem. 2017, 13, 1542–1550, doi:10.3762/bjoc.13.154

• +. 1H NMR allows rapid assessment of spiropyran:merocyanine via measurement and comparison of integrals, and hence enables calculation of [merocyanine]. In turn, [merocyanine] can be applied to quantify the corresponding UV data. Related approaches have employed IR spectroscopy [31] and partial least

Mechanochemical borylation of aryldiazonium salts; merging light and ball milling

• José G. Hernández

Beilstein J. Org. Chem. 2017, 13, 1463–1469, doi:10.3762/bjoc.13.144

• borylated product 3a. In addition to the 1H NMR analysis in solution, this result was confirmed by immediate ex situ analysis using IR spectroscopy of the solid reaction mixture, which revealed only the presence of both starting materials. Thereby, excluding a direct thermal [20][21] or photolysis pathway

1-Imidoalkylphosphonium salts with modulated C_α–P⁺ bond strength: synthesis and application as new active α-imidoalkylating agents

• Jakub Adamek,
• Roman Mazurkiewicz,
• Anna Węgrzyk and
• Karol Erfurt

Beilstein J. Org. Chem. 2017, 13, 1446–1455, doi:10.3762/bjoc.13.142

• , 31P and 19F NMR spectroscopy, as well as IR spectroscopy and HRMS spectrometry. Next the phosphonium salts were used in the Tscherniac–Einhorn–type imidoalkylation of aromatic hydrocarbons of diverse reactivity. The reaction was carried out without a catalyst, using a considerable excess of the

Mechanochemical synthesis of graphene oxide-supported transition metal catalysts for the oxidation of isoeugenol to vanillin

• Ana Franco,
• Sudipta De,
• Alina M. Balu,
• Araceli Garcia and
• Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1439–1445, doi:10.3762/bjoc.13.141

• were characterized by using several techniques including BET, SEM, TEM, XRD, and IR spectroscopy. N2 adsorption/desorption isotherms of the reduced graphene sample (Figure 1a) can be classified as type IV corresponding to the mesoporous materials. The RGO sample showed a BET surface area of 103 m2 g−1

Mechanochemistry-assisted synthesis of hierarchical porous carbons applied as supercapacitors

• Desirée Leistenschneider,
• Nicolas Jäckel,
• Felix Hippauf,
• Volker Presser and
• Lars Borchardt

Beilstein J. Org. Chem. 2017, 13, 1332–1341, doi:10.3762/bjoc.13.130

• polymerization of the educts induced by mechanochemical forces by IR spectroscopy (Figure 2). Two bands at 1703 cm−1 and 1136 cm−1 appear, indicating the formation of the polyester (EG-CA). Likewise, the characteristic bands of the educts (CA: 1210 cm−1; EG: 1418 cm−1) become less pronounced and much broader as

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

Use of costic acid, a natural extract from Dittrichia viscosa, for the control of Varroa destructor, a parasite of the European honey bee

• Kalliopi Sofou,
• Demosthenis Isaakidis,
• Apostolos Spyros,
• Anita Büttner,
• Athanassios Giannis and
• Haralambos E. Katerinopoulos

Beilstein J. Org. Chem. 2017, 13, 952–959, doi:10.3762/bjoc.13.96

• there were discrepancies in the reported 13C NMR spectral data of costic acid [36][37][38] and given the importance of the compound in our biological studies, we decided to perform a full spectroscopic identification of the compound which is briefly described as follows: IR spectroscopy clearly

The synthesis of α-aryl-α-aminophosphonates and α-aryl-α-aminophosphine oxides by the microwave-assisted Pudovik reaction

• Erika Bálint,
• Ádám Tajti,
• Anna Ádám,
• István Csontos,
• Konstantin Karaghiosoff,
• Mátyás Czugler,
• Péter Ábrányi-Balogh and
• György Keglevich

Beilstein J. Org. Chem. 2017, 13, 76–86, doi:10.3762/bjoc.13.10

• compounds. Study on the addition of diethyl phosphite to N-benzylidene(butyl)amine by in situ FTIR spectroscopy Then, we wished to follow the addition reaction of DEP to N-benzylidene(butyl)amine (1a) at 80 °C in acetonitrile (Scheme 2) by in situ Fourier transform IR spectroscopy. Initially the IR spectra

Synthesis of three-dimensional porous hyper-crosslinked polymers via thiol–yne reaction

• Mathias Lang,
• Alexandra Schade and
• Stefan Bräse

Beilstein J. Org. Chem. 2016, 12, 2570–2576, doi:10.3762/bjoc.12.252

• 1 [13], 2 [33] and 4 [34] were synthesized according to literature procedures. The structures of HCPs 3 and 5 were analysed by elemental analysis and IR spectroscopy. The IR spectra of the monomers show the characteristic vibration bands of alkynes at 3300 cm−1 and the vibration band at 2550 cm−1 of

• crosslinking reaction conditions. The obtained HCPs showed BET surface areas up to 650 m²/g and are insoluble in common organic solvents. The characterisation of the networks was performed using IR spectroscopy, elemental analysis, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), powder X

Sydnone C-4 heteroarylation with an indolizine ring via Chichibabin indolizine synthesis

• Florin Albota,
• Mino R. Caira,
• Constantin Draghici,
• Florea Dumitrascu and
• Denisa E. Dumitrescu

Beilstein J. Org. Chem. 2016, 12, 2503–2510, doi:10.3762/bjoc.12.245

• heating pyridines 6a–d with 4-(bromoacetyl)-3-phenylsydnone (7, Scheme 1) in refluxing acetone [5]. The obtained pyridinium salts 8 were used in the next step without further purification. The structures of the pyridinium bromides 8a–d were assigned by 1H NMR, 13C NMR and IR spectroscopy. The chemical

• with an acetylenic dipolarophile. The structures of the new hybrid heterocyclic sydnone-indolizines were assigned by elemental analysis, NMR and IR spectroscopy and X-ray analyses of representative compounds. The latter technique revealed the dipolar alignment of the sydnone moieties in one case and a

• with substituents in both rings and has the advantage over cross-coupling reactions insofar as it overcomes side reactions and uses inexpensive materials. The structures of the new sydnone-indolizine hybrids produced by the Chichibabin synthesis were confirmed by elemental analysis, NMR and IR

Methylenelactide: vinyl polymerization and spatial reactivity effects

• Judita Britner and
• Helmut Ritter

Beilstein J. Org. Chem. 2016, 12, 2378–2389, doi:10.3762/bjoc.12.232

• methylene dioxolanone derivatives yielding predominantly isotactic polymers [15]. Our recently reported spatial dipole–dipole interactions between neighboring lactide units were supported by IR spectroscopy, as the interactions causes two separate carbonyl stretching vibrations. This effect may also play a

• polymers were obtained, the C–H bonds in the linear MLA-polymer units must be more stable than in the monomeric MLA. Otherwise, crosslinking should take place via spontaneous C–H cleavage and chain recombination. This important point could be verified by IR spectroscopy and also by theoretical calculations

• of the force constants of the C–H bonds on a DFT level. The C–H stretching vibrations ν(C-H) = 2948 cm−1 of poly(MLA) determined via IR spectroscopy correlate well with the force constant of k = 473 N m−1 (calculations see Figure S6, Supporting Information File 1). In contrast, the monomer MLA (ν(C-H

Efficient mechanochemical synthesis of regioselective persubstituted cyclodextrins

• Laszlo Jicsinszky,
• Marina Caporaso,
• Katia Martina,
• Emanuela Calcio Gaudino and
• Giancarlo Cravotto

Beilstein J. Org. Chem. 2016, 12, 2364–2371, doi:10.3762/bjoc.12.230

• [22] was also tested. In this case, the final grinding temperature was also found lower, approximately 20 °C lower, than the dry milling and no azido-CD was found by IR spectroscopy in the isolated solid. In the TU reactions, we found that the isolated yields depend on batch-size and we studied the

Hydroxy-functionalized hyper-cross-linked ultra-microporous organic polymers for selective CO₂ capture at room temperature

• Partha Samanta,
• Priyanshu Chandra and
• Sujit K. Ghosh

Beilstein J. Org. Chem. 2016, 12, 1981–1986, doi:10.3762/bjoc.12.185

• under vacuum to get the guest-free desolvated phases of the respective compounds. Infrared (IR) spectroscopy was done first to characterize the constituents of both compounds. A broad peak at ≈3000–3500 cm−1 and two sharp peaks at ≈1465 and ≈1527 cm−1 can be observed in HCP-91 corresponding to the

• using hydroxy-functionalized organic building blocks. Both compounds were characterised thoroughly by IR spectroscopy, TG analysis, solid state 13C NMR technique, FESEM and adsorption measurements. An efficient selective carbon dioxide capture was obtained for both compounds over other flue gases. High

Experimental and theoretical investigations on the high-electron donor character of pyrido-annelated N-heterocyclic carbenes

• Michael Nonnenmacher,
• Dominik M. Buck and
• Doris Kunz

Beilstein J. Org. Chem. 2016, 12, 1884–1896, doi:10.3762/bjoc.12.178

• revealed by IR spectroscopy. The unusually weak π-acceptor character of the dipyridocarbenes was evidenced by the so far lowest 77Se NMR chemical shift for imidazole-derived carbenes. Comparing the electron occupancy in the π-system of the free and the coordinated carbene revealed still a, although very

On the mechanism of imine elimination from Fischer tungsten carbene complexes

• Philipp Veit,
• Christoph Förster and
• Katja Heinze

Beilstein J. Org. Chem. 2016, 12, 1322–1333, doi:10.3762/bjoc.12.125

• carbonyl and CN stretching frequencies (2072, 2018, 1982, 1938, 1889, 1614 cm−1) and relative intensities of partially overlapping bands obtained by IR spectroscopy (Supporting Information File 1, Figure S15) fit to a mixture of W(CO)5(PPh3) ( = 2072, 1982, 1938 cm−1) [87][88], W(CO)4(PPh3)2 in cis