Self-assembly of metallosupramolecular rhombi from chiral concave 9,9’-spirobifluorene-derived bis(pyridine) ligands

• Rainer Hovorka,
• Sophie Hytteballe,
• Torsten Piehler,
• Georg Meyer-Eppler,
• Filip Topić,
• Kari Rissanen,
• Marianne Engeser and
• Arne Lützen

Beilstein J. Org. Chem. 2014, 10, 432–441, doi:10.3762/bjoc.10.40

• , in CD2Cl2 at 298 K). ESI mass spectrum (positive mode) of an 1:1:2 mixture of (R)-3, (S)-6, and [(dppp)Pt(OTf)2] in acetonitrile. Single crystal X-ray structure analysis of [(dppp)2Pd2{(R)-3}2][(dppp)2Pd2{(S)-3}2](OTf)8 obtained from a 1:1 mixture of (rac)-3 and [(dppp)Pd(OTf)2]. (Counterions and

The regioselective synthesis of spirooxindolo pyrrolidines and pyrrolizidines via three-component reactions of acrylamides and aroylacrylic acids with isatins and α-amino acids

• Tatyana L. Pavlovskaya,
• Fedor G. Yaremenko,
• Victoria V. Lipson,
• Svetlana V. Shishkina,
• Oleg V. Shishkin,
• Vladimir I. Musatov and
• Alexander S. Karpenko

Beilstein J. Org. Chem. 2014, 10, 117–126, doi:10.3762/bjoc.10.8

• obtained by the above method were characterized by mass spectrometry, 1H and 13C NMR, and elemental analyses. The regiochemical outcome of the cycloaddition was unambiguously confirmed by NOE experiments in 1H NMR as well as later by a single crystal X-ray structure analysis of the cycloadduct 4a. The 1H

Advancements in the mechanistic understanding of the copper-catalyzed azide–alkyne cycloaddition

• Regina Berg and
• Bernd F. Straub

Beilstein J. Org. Chem. 2013, 9, 2715–2750, doi:10.3762/bjoc.9.308

• copper(I) complexes, which are highly active in CuAAC reactions on water or under neat conditions (Scheme 7) [130]. Albeit no single crystals of the copper(I) complex shown in Scheme 7 could be grown, NMR measurements as well as a single crystal X-ray structure of an analogous C186tren-complex with CuCl2

• complex (Scheme 8) [131]. In 2008, the group of Donnelly was able to crystallize a dinuclear copper(I)-TBTA complex from TBTA and tetrakis(acetonitrile)copper(I) tetrafluoroborate under anaerobic conditions in acetonitrile [131]. The single crystal X-ray structure shows a dinuclear dication [Cu2(μ-TBTA

• complex [(SIMes)CuCl(phen)] could be isolated as red crystals and a single crystal X-ray structure shows a distorted tetrahedral coordination geometry at the metal centre. Peak broadening indicative of ligand exchange was observed on the NMR time scale and the association constant of phenanthroline was

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

• single crystal X-ray structure of carmegliptin bound in the human DPP-4 active site has been published indicating how the fluoromethylpyrrolidone moiety extends into an adjacent lipophilic pocket [81]. Additional binding is provided by π–π interaction between the aromatic substructure and an adjacent

Synthesis of the reported structure of piperazirum using a nitro-Mannich reaction as the key stereochemical determining step

• James C. Anderson,
• Andreas S. Kalogirou,
• Michael J. Porter and
• Graham J. Tizzard

Beilstein J. Org. Chem. 2013, 9, 1737–1744, doi:10.3762/bjoc.9.200

• [56]. Further stereochemical proof was provided by a single crystal X-ray structure determination of 2·HCl (vide infra). We presumed again that the primary amine of 21 would be more nucleophilic towards a keto acid derivative 5. In order to obtain a piperazinone of the desired connectivity (23) a keto

• recording of NMR spectra in D2O, but again the chemical shifts were inconsistent with those reported. Single crystal X-ray structure determination of 2 proved unambiguously the assigned structure obtained from spectroscopic data (Figure 1) [59]. Conclusion The rapid synthesis of r-3,c-5-diisobutyl-c-6

Use of 3-[¹⁸F]fluoropropanesulfonyl chloride as a prosthetic agent for the radiolabelling of amines: Investigation of precursor molecules, labelling conditions and enzymatic stability of the corresponding sulfonamides

• Reik Löser,
• Steffen Fischer,
• Achim Hiller,
• Martin Köckerling,
• Uta Funke,
• Aurélie Maisonial,
• Peter Brust and
• Jörg Steinbach

Beilstein J. Org. Chem. 2013, 9, 1002–1011, doi:10.3762/bjoc.9.115

• resulting sulfonamides was confirmed with the aid of the corresponding nonradioactive reference compounds. For one of these, N-(4-nitrophenyl)-3-fluoropropane-1-sulfonamide (18), the single-crystal X-ray structure was determined. The formation of 18F-labelled sulfonamides derived from aliphatic amines did

Facile synthesis of functionalized spiro[indoline-3,2'-oxiran]-2-ones by Darzens reaction

• Qin Fu and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2013, 9, 918–924, doi:10.3762/bjoc.9.105

• structures of the spiro compounds 5a–p were also established by spectroscopic methods and were confirmed by single-crystal X-ray structure determination of compound 5o (Figure 3). 1H NMR spectra showed that a mixture of cis/trans isomers existed in most samples with a large range of different cis/trans

Design and synthesis of a photoswitchable guanidine catalyst

• Philipp Viehmann and
• Stefan Hecht

Beilstein J. Org. Chem. 2012, 8, 1825–1830, doi:10.3762/bjoc.8.209

• 2E. The therefore necessary urea 4 can be obtained from the addition of pyrrolidine to phenylisocyanate (3). The structure of guanidine 2E was proven by NMR spectroscopy, HRMS, as well as by single-crystal X-ray structure analysis (Figure 1). To our knowledge, this is the first example of an X-ray

• catalytic inactivity of guanidine 2E is indeed caused by the guanidine core itself. Besides the previously mentioned basicity issue, a possible reason for this behavior may be discerned from the single-crystal X-ray structure analysis of guanidine 2E. It can be seen that, in contrast to the supposed

• introducing sterically crowded substituents or ring constraints in order to direct the position of the relevant lone pair of guanidine as well as the NH-function. ORTEP image of the single-crystal X-ray structure of guanidine 2E, as well as a rotated close-up of the guanidine moiety, showing 50% thermal

Metal–ligand multiple bonds as frustrated Lewis pairs for C–H functionalization

• Matthew T. Whited

Beilstein J. Org. Chem. 2012, 8, 1554–1563, doi:10.3762/bjoc.8.177

• ]. Single-crystal X-ray structure of a silver(I) triflate adduct of (PNP)Ir═C(H)Ot-Bu with most H atoms and phosphine substituents (except ipso carbon atoms) omitted for clarity. Heterolytic cleavage of H2 by a phosphine/borane FLP by H2 polarization in the P–B cavity [5][11]. Insertion of carbon dioxide

• and nitrene-group transfer to a Mδ−═Eδ+ FLP [18][78]. Supporting Information Supporting Information File 414: The single-crystal X-ray structure of [(PNP)Ir═C(H)Ot-Bu][AgOTf] is supplied in CIF format and has been deposited with the CCDC, No. 889634. Acknowledgements Acknowledgment is made to the

Valence isomerization of cyclohepta-1,3,5-triene and its heteroelement analogues

• Helen Jansen,
• J. Chris Slootweg and
• Koop Lammertsma

Beilstein J. Org. Chem. 2011, 7, 1713–1721, doi:10.3762/bjoc.7.201

• -shape structure with alternating C=C bonds for 3 [39][40], which was supported by single-crystal X-ray structure analyses of simple derivatives [41]. Table 1 also summarizes the relative energies obtained by high-level theoretical calculations for the parent heteropines and the corresponding bicyclic

• -benzophosphepine, 32) [7][102][103][104][105][106][107]. The single-crystal X-ray structure analysis of phenyl-substituted phosphepine 33 (Scheme 7) also showed a flattened-boat conformation (α = 40.5°, β = 28.2°) [5] compared to the metal-free parent structure (α = 48.3°, β = 27.8°), computed at the B3PW91/6-311

Photochemical and thermal intramolecular 1,3-dipolar cycloaddition reactions of new o-stilbene-methylene-3-sydnones and their synthesis

• Kristina Butković,
• Željko Marinić,
• Krešimir Molčanov,
• Biserka Kojić-Prodić and
• Marija Šindler-Kulyk

Beilstein J. Org. Chem. 2011, 7, 1663–1670, doi:10.3762/bjoc.7.196

• which the expulsion of nitrogen is possible. The structure 14 (Scheme 6) was determined by additional NMR techniques, NOE and HMBC interactions, and by single crystal X-ray structure analysis (Figure 4) of the crystal formed in an NMR tube by slow evaporation of the solvent. Also, when compound 3b (cis

Single enantiomer synthesis of α-(trifluoromethyl)-β-lactam

• Václav Jurčík,
• Alexandra M. Z. Slawin and
• David O'Hagan

Beilstein J. Org. Chem. 2011, 7, 759–766, doi:10.3762/bjoc.7.86

• illustrated in Scheme 2. The presence of the naphthyl ring in amine (R)-3c rendered the resultant β-lactam diastereoisomers 5c more crystalline, and a single crystal X-ray structure was solved for the major-diastereomer revealing the (αR,3R)-5c configuration. The structure is shown in Figure 2b. With this

Comparison of zwitterionic N-alkylaminomethanesulfonic acids to related compounds in the Good buffer series

• Robert D. Long,
• Newton P. Hilliard Jr,
• Suneel A. Chhatre,
• Tatiana V. Timofeeva,
• Andrey A. Yakovenko,
• Daniel K. Dei and
• Enoch A. Mensah

Beilstein J. Org. Chem. 2010, 6, No. 31, doi:10.3762/bjoc.6.31

• , t, J = 6.3), 3.81 (2H, s). 13C NMR (62.9 MHz, MeOD): δ 52.5, 54.0, 59.2, 60.7, 74.2. Anal. Calcd for C7H17N2NaO5S·H2O: C, 31.81%; H, 6.48%; N, 10.60%; Na, 8.70%; O, 30.27%; S, 12.13%. Found: C, 30.72%; H, 6.48%; N, 10.22%; S, 10.82%. Structure assignment supported by single crystal X-ray structure

• = 4.8), 3.76 (4H, t, J = 4.8), 3.8 (2H, s); 13C NMR (125 MHz, D2O/TSP): δ 54.7 (t), 69.2 (t), 75.8 (s). Anal. Calcd for C5H11NO4S·0.5Na: C, 31.24%; H, 5.51%; N, 7.29%; Na, 5.98%; O, 33.30%; S, 16.68%. Found: C, 31.05%; H, 6.13%; N, 7.63%; S, 16.66%. Structure assignment supported by single crystal X-ray

• structure of the sodium salt form (in Supporting Information File 2). N-(2-hydroxyethyl)piperazine-N′-methanesulfonic acid [HEPMS] (2). This was prepared as the sodium salt monohydrate by the general procedure from 0.200 mol of 1-(2-hydroxyethyl)piperazine (24.5 mL), yielding 49.2 g (0.186 mol) of 2 (93

Shape- persistent macrocycle with intraannular alkyl groups: some structural limits of discotic liquid crystals with an inverted structure

• Sigurd Höger,
• Jill Weber,
• Andreas Leppert and
• Volker Enkelmann

Beilstein J. Org. Chem. 2008, 4, No. 1, doi:10.1186/1860-5397-4-1

• ; c) Structure of the shape-persistent macrocycle 1 containing extraannular methyl groups, intraannular octadecyloxy groups and adaptable propyloxy groups. Single crystal X-ray structure of 9a (solvent not shown): a) Top view; b) Side view of two molecules of 9a in the crystal. Synthesis of

Vinylogous Mukaiyama aldol reactions with 4-oxy-2-trimethylsilyloxypyrroles: relevance to castanospermine synthesis

• Roger Hunter,
• Sophie C. M. Rees-Jones and
• Hong Su

Beilstein J. Org. Chem. 2007, 3, No. 38, doi:10.1186/1860-5397-3-38

• 15 in 91% yield. This was then desilylated with TBAF at 10°C for 5 days to give alcohol 16 in 84% yield. These conditions were chosen, as by-products formed at higher temperature. Adduct 16 was crystallized from ethyl acetate and hexane and used to obtain a single-crystal X-ray structure (Figure 4

Aroylketene dithioacetal chemistry: facile synthesis of 4-aroyl- 3-methylsulfanyl- 2-tosylpyrroles from aroylketene dithioacetals and TosMIC

• H. Surya Prakash Rao and
• S. Sivakumar

Beilstein J. Org. Chem. 2007, 3, No. 31, doi:10.1186/1860-5397-3-31

• were separated from minor amount of the imidazole 4 contaminant by column chromatography. The structure of 3b was confirmed on the basis of the single crystal X-ray structure analysis (deposited with Cambridge Crystallographic Data Center (CCDC); deposition No. 628766). The structure of AKDTAs 1b-g

The first salen- type ligands derived from 3',5'-diamino- 3',5'-dideoxythymidine and -dideoxyxylothymidine and their corresponding copper(II) complexes

• Daniel Koth,
• Michael Gottschaldt,
• Helmar Görls and
• Karolin Pohle

Beilstein J. Org. Chem. 2006, 2, No. 17, doi:10.1186/1860-5397-2-17

• ',5'-bis(3,5-di-tert-butylsalicylaldiminato)-3',5'-dideoxyxylothymidine-copper(II) could be determined by single crystal X-ray structure analysis. The copper centre in this complex has distorted tetrahedral coordination geometry. Conclusion For the synthesis of 3',5'-diamino-3',5'-dideoxy thymidines

• formed uncharged stable copper(II) complexes with double deprotonated ligands as MS experiments had shown. Recrystallization of complex 13 using DMF resulted in crystals suitable for single crystal X-ray structure analysis [15] (For details see also: Figure 1 and Supporting Information File 1). The