Preparation and NMR spectra of four isomeric diformyl[2.2]paracyclophanes (cyclophanes 66)

Dix, Ina; Hopf, Henning; Satyanarayana, Thota B N; Ernst, Ludger

doi:10.3762/bjoc.6.104

Cited by 15 publications

(21 citation statements)

References 13 publications

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“…The structure of the product was confirmed by 1 H and 13 C NMR spectral analysis, and the data matched well with the reported results [17]. Furthermore, the 1 H NMR spectra of the CH 2 CH 2 bridge in the paracyclophane structure was consistent with the data reported in the literature, which also identified the 4,7,12,15-tetrachloro isomer [21]. …”

Section: Resultssupporting

confidence: 88%

A new protocol for the synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane

Pan

Wang

Xiao

2016

Beilstein J. Org. Chem.

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We report a green and convenient protocol to prepare 4,7,12,15-tetrachloro[2.2]paracyclophane, the precursor of parylene D, from 2,5-dichloro-p-xylene. In the first bromination step, with H2O2–HBr as a bromide source, this procedure becomes organic-waste-free and organic-solvent-free and can appropriately replace the existing bromination methods. The Winberg elimination–dimerization step, using aqueous sodium hydroxide solution instead of silver oxide for anion exchange, results in a significant improvement in product yield. Furthermore, four substituted [2.2]paracyclophanes were also prepared in this convenient way.

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Section: Resultssupporting

confidence: 88%

A new protocol for the synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane

Pan

Wang

Xiao

2016

Beilstein J. Org. Chem.

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“…These provide the isomeric bisformyl [2.2]paracyclophanes 178 to 181 in about equal ratio and in a total yield of up to 45% [127]. The apparently disadvantageous production of a mixture of isomers is not a real handicap of this route since these adducts differ in their physical properties (polarity, solubility) strongly enough to allow easy separation/purification by chromatography and/or recrystallization.…”

Section: Reviewmentioning

confidence: 99%

The chemistry of bisallenes

Hopf¹,

Μαρκόπουλος²

2012

Beilstein J. Org. Chem.

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SummaryThis review describes the preparation, structural properties and the use of bisallenes in organic synthesis for the first time. All classes of compounds containing at least two allene moieties are considered, starting from simple conjugated bisallenes and ending with allenes in which the two cumulenic units are connected by complex polycyclic ring systems, heteroatoms and/or heteroatom-containing tethers. Preparatively the bisallenes are especially useful in isomerization and cycloaddition reactions of all kinds leading to the respective target molecules with high atom economy and often in high yield. Bisallenes are hence substrates for generating molecular complexity in a small number of steps (high step economy).

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“…Isomers 1 and 2a were prepared as previously described [4,5] and crystallized by evaporation from a solution in chloroform. Isomer 2b was prepared as previously described [8] and crystallized from a solution in dichloromethane.…”

Section: Methodsmentioning

confidence: 99%

“…The preparation, separation and spectroscopic identification of these isomers has recently been described [4], but the crystallographic aspects were omitted. In fact all four isomers were crystallographically characterized [5], but two, the pseudo-para and pseudo-gem isomers, proved to be severely disordered.…”

Section: Introductionmentioning

confidence: 99%

Isomers of Diformyl[2.2]paracyclophane; X-Ray Structure Determinations of the Pseudo-ortho Isomer and Two Polymorphs of the Pseudo-meta Isomer

Jones

Dix

Negru

et al. 2011

Zeitschrift Für Naturforschung B

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Pseudo-ortho-or 4,16-diformyl[2.2]paracyclophane (1) and two polymorphs of pseudo-meta-or 4,13-diformyl[2.2]paracyclophane (2) all display the usual features of [2.2]paracyclophane strain (lengthened C-C bonds and widened C-C(sp 3 )-C angles in the bridges, narrower sp 2 ring angles at the bridgehead atoms, and flattened boat conformations of the rings). All bulk samples were racemates. Polymorph 2a crystallizes in space group P2 1 /n with one molecule in a general position, whereas 2b crystallizes in space group C2 with two independent molecules, each with crystallographic twofold symmetry. All three molecules of 2 are different rotamers with respect to the formyl groups; in 2a one is endo and one exo to the neighbouring bridge, whereas in 2b both formyls are exo in one molecule and endo in the other. In all compounds, the packing patterns are preponderantly associated with C-H···O contacts. In 1 the molecules are connected to form tubes parallel to the short a axis. 2a consists of two interconnected layer structures. One is parallel to (100) and involves chains of molecules parallel to [011]; the other is parallel to (001) and involves chains of molecules parallel to the b axis. 2b consists of two hexagonal layers, one for each independent molecule, parallel to (001). One layer contains bifurcated (C-H···) 2 O systems, whereas the single H···O interactions in the other are long and markedly bent.

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Preparation and NMR spectra of four isomeric diformyl[2.2]paracyclophanes (cyclophanes 66)

Cited by 15 publications

References 13 publications

A new protocol for the synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane

A new protocol for the synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane

The chemistry of bisallenes

Isomers of Diformyl[2.2]paracyclophane; X-Ray Structure Determinations of the Pseudo-ortho Isomer and Two Polymorphs of the Pseudo-meta Isomer

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