Synthesis of novel N-cyclopentenyl-lactams using the Aubé reaction

• Madhuri V. Shinde,
• Rohini S. Ople,
• Ekta Sangtani,
• Rajesh Gonnade and
• D. Srinivasa Reddy

Beilstein J. Org. Chem. 2015, 11, 1060–1067, doi:10.3762/bjoc.11.119

• explained by the reagent approach from the opposite side of both substituents present on the cyclopentene ring. We have assigned the structure based on the spectral data (see Experimental). In addition, crystals of the triol (±)-12 were obtained and single crystal X-ray analysis further established the

Inclusion of trans-resveratrol in methylated cyclodextrins: synthesis and solid-state structures

• Lee Trollope,
• Dyanne L. Cruickshank,
• Terence Noonan,
• Susan A. Bourne,
• Milena Sorrenti,
• Laura Catenacci and
• Mino R. Caira

Beilstein J. Org. Chem. 2014, 10, 3136–3151, doi:10.3762/bjoc.10.331

• important goal was the isolation of RSV·CD inclusion complexes in crystalline form so that definitive details of the mode of inclusion of the RSV molecule and the packing of complex units could be established by single crystal X-ray analysis. In view of its extended shape and apparent rigidity, the RSV

A one-pot multistep cyclization yielding thiadiazoloimidazole derivatives

• Debabrata Samanta,
• Anup Rana,
• Jan W. Bats and
• Michael Schmittel

Beilstein J. Org. Chem. 2014, 10, 2989–2996, doi:10.3762/bjoc.10.317

• unit. The structure of the intricate heterocycle 2a was confirmed by single-crystal X-ray analysis and its mechanism of formation supported by DFT computations. Keywords: carbodiimide; cyclization; dithiourea; DFT; 1,2,4-thiadiazoles; Introduction Heterocyclic rings are key components in many

• residues. All compounds were characterized by 1H, 13C, 1H,1H COSY NMR, IR, and as well as elemental analysis. In addition to solution state characterization, the structure of 2a (Figure 1) was addressed by single-crystal X-ray analysis. The unit cell of the crystal comprises four molecules linked together

• carbodiimide and thiourea units under in situ conditions. The product structure was confirmed by single crystal X-ray analysis in the solid state. The substitution pattern (aryl, benzyl, sec-alkyl) may be varied easily to achieve potentially biologically active compounds with interesting properties. The free

Superoxide chemistry revisited: synthesis of tetrachloro-substituted methylenenortricyclenes

• Basavaraj M. Budanur and
• Faiz Ahmed Khan

Beilstein J. Org. Chem. 2014, 10, 2531–2538, doi:10.3762/bjoc.10.264

• olefinic peaks in the 13C NMR are not in accordance with our expectations. The single crystal X-ray analysis of the product (Figure 1) sorted out all the ambiguity associated with structure. To our pleasant surprise the structure of the product was methylenenortricyclene 5a which seems to have been formed

• observe acylation on the double bond and not on the cyclopropane ring to give 2-propanone-substituted pentachloronorbornene derivatives 8 (Table 2). The structure of 8a was unambiguously proved by single crystal X-ray analysis (Figure 2). A plausible mechanism involving the initial nucleophilic attack of

Derivatives of the triaminoguanidinium ion, 3. Multiple N-functionalization of the triaminoguanidinium ion with isocyanates and isothiocyanates

• Jan Szabo,
• Kerstin Karger,
• Nicolas Bucher and
• Gerhard Maas

Beilstein J. Org. Chem. 2014, 10, 2255–2262, doi:10.3762/bjoc.10.234

• (Scheme 3), the structure of which was confirmed by single-crystal X-ray analysis (Figure 2, vide infra for a structural comparison with 7a). When (p-toluenesulfonyl) isocyanate instead of phenyl isocyanate was allowed to react with 1,2,3-tris(benzylamino)guanidinium chloride (3), a mono-ureido 1,2,3

Five-membered ring annelation in [2.2]paracyclophanes by aldol condensation

• Henning Hopf,
• Swaminathan Vijay Narayanan and
• Peter G. Jones

Beilstein J. Org. Chem. 2014, 10, 2021–2026, doi:10.3762/bjoc.10.210

• phane derivatives could be developed by employing aldol-type reactions of the tetraacetyl derivative 9. This tetraketone (whose “twisted” structure was determined by single-crystal X-ray analysis [7] as shown in Scheme 2) is readily available by adding hex-3-yne-2,5-dione (7) to the diene hexa-1,2,4,5

• , both at room temperature), only two of the possible six isomers (see above) are actually formed. To these we assign structures 12 and 15 (product ratio 30:70), i.e., the aldols are syn,endo,endo- and anti,endo,endo-isomers. For the former compound the structure assignment follows from single-crystal X

• -ray analysis of its deuteriochloroform solvate. The asymmetric unit is shown in Figure 1. The structure of 12 displays approximate C2 symmetry, with a r.m.s. deviation of 0.05 Å. It shows the normal distortions associated with the [2.2]paracyclophane geometry, with lengthened bridge bonds, widened sp3

Building complex carbon skeletons with ethynyl[2.2]paracyclophanes

• Ina Dix,
• Lidija Bondarenko,
• Peter G. Jones,
• Thomas Oeser and
• Henning Hopf

Beilstein J. Org. Chem. 2014, 10, 2013–2020, doi:10.3762/bjoc.10.209

• 19 and 20 (total yield 78%) which both could be obtained in pure and crystalline form by repeated chromatography and recrystalli-zation. The final structural proof was again provided by single crystal X-ray analysis (Figure 3 and Figure 4). Compound 19 (Figure 3) has approximate mirror symmetry

• single-crystal X-ray analysis (Figure 5); all other analytical and spectroscopic data are collected in the experimental section (see Supporting Information File 1). The “crossed” derivative 22, with its relatively short extra acetylenic bridges and with the clamping effect of the ring C5–C10, is

• last step is prohibitive. Instead it prefers the isomerization to the isolated CpCo-complex 26. Compound 26 was identified by its spectroscopic data (see Supporting Information File 1) and also by a single-crystal X-ray analysis. The result is displayed in Figure 6. The cobalt complex 26 shows

Reaction of selected carbohydrate aldehydes with benzylmagnesium halides: benzyl versus o-tolyl rearrangement

• Maroš Bella,
• Bohumil Steiner,
• Vratislav Langer and
• Miroslav Koóš

Beilstein J. Org. Chem. 2014, 10, 1942–1950, doi:10.3762/bjoc.10.202

• unambiguously confirmed by single-crystal X-ray analysis. The formation of o-tolyl isomers 4 and 5 can be explained by the possible reaction sequence (path 1) depicted in Scheme 2. The first step involves an addition of the Grignard reagent to the saccharide aldehyde, producing a trienic magnesium alkoxide

One-pot stereoselective synthesis of α,β-differentiated diamino esters via the sequence of aminochlorination, aziridination and intermolecular S_N2 reaction

• Yiwen Xiong,
• Ping Qian,
• Chenhui Cao,
• Haibo Mei,
• Jianlin Han,
• Guigen Li and
• Yi Pan

Beilstein J. Org. Chem. 2014, 10, 1802–1807, doi:10.3762/bjoc.10.189

• of product 5o had a good crystallinity and were suitable for single crystal X-ray analysis (Figure 1). Crystallographic analysis has revealed that the anti-vicinal diamino ester was obtained. As a result, the stereochemistry of the other products was assigned (anti-isomer) based on the similarity of

Rational design of cyclopropane-based chiral PHOX ligands for intermolecular asymmetric Heck reaction

• Marina Rubina,
• William M. Sherrill,
• Alexey Yu. Barkov and
• Michael Rubin

Beilstein J. Org. Chem. 2014, 10, 1536–1548, doi:10.3762/bjoc.10.158

• thermodynamically disfavored compared to I1. This hypothesis was also supported by a single crystal X-ray analysis of (L1)PdCl2 complex (Figure 4). The resolved crystal structure clearly shows that the syn-(C14) and anti-substituent (C18) at phosphorus adopt a pseudo-equatorial and a pseudo-axial position

The influence of intraannular templates on the liquid crystallinity of shape-persistent macrocycles

• Joscha Vollmeyer,
• Ute Baumeister and
• Sigurd Höger

Beilstein J. Org. Chem. 2014, 10, 910–920, doi:10.3762/bjoc.10.89

• ]. Amphiphilic macrocycles in aqueous solution have been shown to be able to form vesicles [24][25]. In the bulk state, most of the macrocycles crystallize and some could be explored by single-crystal X-ray analysis [26][27][28]. Heating crystalline macrocycles above the melting point does not always lead

Dimerisation, rhodium complex formation and rearrangements of N-heterocyclic carbenes of indazoles

• Zong Guan,
• Jan C. Namyslo,
• Martin H. H. Drafz,
• Martin Nieger and
• Andreas Schmidt

Beilstein J. Org. Chem. 2014, 10, 832–840, doi:10.3762/bjoc.10.79

• observable in NMR spectra at standard temperature conditions. The spiro compound 14c crystallized from a saturated solution in n-hexane so that we were able to perform a single crystal X-ray analysis. The compound crystallized monoclinic. As expected, neither the pyrrole ring nor the pyrazole ring is planar

• crystal X-ray analysis of one of the E-isomers, which equilibrate in solution as well as in the solid state. Heating of the indazole–indole spiro compounds results in the formation of quinazolines by a ring-cleavage/ring-closure sequence (X-ray analysis). Results of DFT calculations are presented

• -ylidenes spontaneously dimerize under ring cleavage of one of the N,N-bonds and ring closure to an indazole–indole spiro compound which possesses an exocyclic imine group. The E/Z isomers of the imines can be separated by column chromatography when methanol is used as eluent. We present results of a single

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

• azomethine ylide, which regioselectively adds to the C=C bond of acrylamide or aroylacrylic acid. Since the stereochemistry of the cycloadducts 4a and 6a was clarified by a single-crystal X-ray analysis, the structures of the reacting systems – the azomethine ylide and dipolarophiles (acrylamide and

The preparation of several 1,2,3,4,5-functionalized cyclopentane derivatives

• André S. Kelch,
• Peter G. Jones,
• Ina Dix and
• Henning Hopf

Beilstein J. Org. Chem. 2013, 9, 1705–1712, doi:10.3762/bjoc.9.195

• -configuration of the substituents at the five-membered ring, as was shown by single crystal X-ray analysis (Figure 1). It is unclear at the present time whether the correspondingly configurated pentaalcohol was already present in the starting material 16 as a side-product, which had been overlooked in previous

Isolation and X-ray characterization of palladium–N complexes in the guanylation of aromatic amines. Mechanistic implications

• Abdessamad Grirrane,
• Hermenegildo Garcia and
• Eleuterio Álvarez

Beilstein J. Org. Chem. 2013, 9, 1455–1462, doi:10.3762/bjoc.9.165

• were fully characterized by analytical and spectroscopic data (see Supporting Information File 1, experimental section). Structure of guanidine 5a was confirmed by single-crystal X-ray analysis, Figure 4 shows the corresponding ORTEP for compound 5a as well as some views of the crystal packing (see

Synthesis of the tetracyclic core of Illicium sesquiterpenes using an organocatalyzed asymmetric Robinson annulation

• Lynnie Trzoss,
• Jing Xu,
• Michelle H. Lacoske and
• Emmanuel A. Theodorakis

Beilstein J. Org. Chem. 2013, 9, 1135–1140, doi:10.3762/bjoc.9.126

• the C-1 center (dr = 9:1) in 81% yield (over three steps) [76]. The stereochemistry of 15 was unambiguously confirmed by single-crystal X-ray analysis of the related tosylate derivative 16 [77]. Deoxygenation of the C-15 primary alcohol was performed by: (a) mesylation of the alcohol with MsCl; and (b

Direct alkenylation of indolin-2-ones by 6-aryl-4-methylthio-2H-pyran-2-one-3-carbonitriles: a novel approach

• Sandeep Kumar,
• Ramendra Pratap,
• Abhinav Kumar,
• Brijesh Kumar,
• Vishnu K. Tandon and
• Vishnu Ji Ram

Beilstein J. Org. Chem. 2013, 9, 809–817, doi:10.3762/bjoc.9.92

• -oxindoles. Furthermore, the synthesis of 8y and its relative stability with respect to the other tautomers has been confirmed by single-crystal X-ray analysis and quantum chemical calculations. X-ray diffraction displayed various C−H…π, C−H…O and Ar-H…π intermolecular interactions. These interactions have

Spin state switching in iron coordination compounds

• Philipp Gütlich,
• Ana B. Gaspar and
• Yann Garcia

Beilstein J. Org. Chem. 2013, 9, 342–391, doi:10.3762/bjoc.9.39

Inclusion of the insecticide fenitrothion in dimethylated-β-cyclodextrin: unusual guest disorder in the solid state and efficient retardation of the hydrolysis rate of the complexed guest in alkaline solution

• Dyanne L. Cruickshank,
• Natalia M. Rougier,
• Raquel V. Vico,
• Susan A. Bourne,
• Elba I. Buján,
• Mino R. Caira and
• Rita H. de Rossi

Beilstein J. Org. Chem. 2013, 9, 106–117, doi:10.3762/bjoc.9.14

• ]. Theoretical calculation of the energies of the two types of complexes in the gas phase indicates that there is no significant difference in their values [24]. Single-crystal X-ray analysis shows that for β-CD and TRIMEB, complexes of type A are formed while for DIMEB (see above) in the unit cell a small

• bonds that link neighbouring methylglucose residues. As a result, there is more available space in the cavity of a DIMEB molecule than in that of a TRIMEB molecule, and therefore the guest fenitrothion can penetrate further into the cavity. Conclusion Single-crystal X-ray analysis of the 1:1 DIMEB

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

• deposited at the Cambridge Crystallographic Data Centre and allocated the deposition number CCDC 891016. Supporting Information File 404: Experimental details and spectra. Acknowledgements We thank Stefan Mebs (HU Berlin) for carrying out the single-crystal X-ray analysis. Generous support by the German

The crystal structure of the Dess–Martin periodinane

• Albert Schröckeneder,
• Desiree Stichnoth,
• Peter Mayer and
• Dirk Trauner

Beilstein J. Org. Chem. 2012, 8, 1523–1527, doi:10.3762/bjoc.8.172

• crystallinity of the compound. Indeed, microcrystalline 1 precipitates from the acetic anhydride solution upon cooling at the end of the procedure used for its preparation. Various recrystallization methods also yielded 1 as a microcrystalline powder that was unsuitable for single-crystal X-ray analysis

Expanding the chemical diversity of spirooxindoles via alkylative pyridine dearomatization

• Chunhui Dai,
• Bo Liang and
• Corey R. J. Stephenson

Beilstein J. Org. Chem. 2012, 8, 986–993, doi:10.3762/bjoc.8.111

• exclusively in 74% yield (Table 1, entry 10). We predict that the formation of 6j by dehydration is due to the electron deficiency of the oxindole ring and subsequent stability gained from the ene–trione moiety. The structure of compound 6b was established by single-crystal X-ray analysis (Figure 1). Having

• , generated during the reaction, to react with pyridine. Finally, the structure of compound 3d was established by single-crystal X-ray analysis (Figure 2). Further plans to expand the molecular diversity of these compounds utilizing available functionalities are currently underway. As an illustrative example

• products 8a–c were isolated in moderate yields. Finally, the structure of compound 8a was established by single-crystal X-ray analysis (Figure 3). Conclusion In summary, we developed a practical and efficient method to synthesize spirooxindole derivatives with a [1,3]oxazine fused-ring system. The reaction

Carbohydrate-auxiliary assisted preparation of enantiopure 1,2-oxazine derivatives and aminopolyols

• Marcin Jasiński,
• Dieter Lentz and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2012, 8, 662–674, doi:10.3762/bjoc.8.74

• , 128.1, 128.8, 138.6 (3 d, s, Ph) ppm; IR (ATR) : 3490–3230 (O-H, N-H), 3065–2810 (=C-H, C-H), 1075 (C-O) cm−1; ESI–TOF (m/z): [M + H]+ calcd for C11H18NO3, 212.1292; found, 212.1282. By-products 4 and 5 isolated from the reaction of nitrone 1a with lithiated methoxyallene. Single-crystal X-ray analysis

Stereoselective, nitro-Mannich/lactamisation cascades for the direct synthesis of heavily decorated 5-nitropiperidin-2-ones and related heterocycles

• Pavol Jakubec,
• Dane M. Cockfield,
• Madeleine Helliwell,
• James Raftery and
• Darren J. Dixon

Beilstein J. Org. Chem. 2012, 8, 567–578, doi:10.3762/bjoc.8.64

• stereochemistry of the major diastereomer 6e was assigned unambiguously by single-crystal X-ray analysis. With a range of suitable test substrates in hand, formaldehyde-derived imines were then investigated in the nitro-Mannich/lactamisation reaction. Aqueous formaldehyde (3a) and allylamine (4a) were added to a

• observed in each case and the reaction products 1d–g were obtained in moderate to good yields (50–74%). The relative stereochemistry of 1g was assigned unambiguously by single-crystal X-ray analysis. Similarly, variation at position 1 required the use of an alternative amine for in situ imine formation

Synthesis of fused tricyclic amines unsubstituted at the ring-junction positions by a cascade condensation, cyclization, cycloaddition then decarbonylation strategy

• Iain Coldham,
• Adam J. M. Burrell,
• Hélène D. S. Guerrand,
• Luke Watson,
• Nathaniel G. Martin and
• Niall Oram

Beilstein J. Org. Chem. 2012, 8, 107–111, doi:10.3762/bjoc.8.11

• cycloadduct 14 as a single diastereoisomer (Scheme 5). Deprotection of the silyl ether with tetra-n-butylammonium fluoride (TBAF) gave the alcohol 15, then Swern oxidation yielded aldehyde 16. The stereochemistry of alcohol 15 was confirmed by single crystal X-ray analysis. This stereochemistry was expected