Organische Schwefelverbindungen,97. Friedel‐Crafts‐Reaktionen mit Thiosäurechloriden

Viola, H.; Scheithauer, Steffen; Mayer, Roland

doi:10.1002/cber.19681011024

Cited by 35 publications

(8 citation statements)

References 23 publications

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“…Ethyl(p-pheny1)dithiobenzoate (1 ) This was obtained according to the method of Mayer [33], reacting 2 g of biphenyl with 1.6 ml of ethyl dithiochloroformiate [34] 6.3. I-Ethylthio-1-(p-phenyt )phenyl-, 2,2-diphenyl ethene (4) 0.032g of (3) and 0.020g of triphenylphosphine were dissolved in 20ml of anhydrous benzene and refluxed under N, till the disappearance of the starting episulphide (TLC).…”

Section: Methodsmentioning

confidence: 99%

Searching for asymmetric inductions in chiral smectic mesophases

Finzi¹,

Maccagnani²,

Masiero³

et al. 1989

Liquid Crystals

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Searching for asymmetric synthesis in smectic phases is, to our knowledge, reported for the first time in this paper. Two different reactions able to lead to optical enrichment were carried out in smectic phases (S) composed of chiral molecules. The first was a thermally promoted 1,3 dipolar cycloaddition of a diazo compound to a prochiral thiocarbonyl derivative run in a chiral smectic C mesophase (S,*). The second was a monomolecular process, the photochemical inversion of chiral sulphoxides in a smectic A mesophase. In both cases the asymmetric induction was zero or, in the best run, very very poor. This lack of transfer of chirality between the smectic solvent and the reaction is discussed to understand better the requirements for more successful tailoring of such experiments. IntroductionMany of the processes taking place in biological systems (such as enzymatic catalysis [l]) are determined not only by the chemistry of the individual reagents, products and biological catalysers, but also, by the specific interactions between these species with themselves and with their environment. That is why part of synthetic chemistry is today engaged in obtaining multi-molecular systems with a high degree of internal organization, able to reproduce the activity of molecules occurring in natural systems [2, 31, or able to be used as simplified models in order to study the effect of supramolecular parameters on the path of the reaction [4]. The reactivity of solute molecules can be modified within structurally organized solvents (such as liquid crystals [5-71, vesicles [8], micelles [9, 101 and membranes [ll]). These reactivity controls can be considered as true catalytic effects and are determined by anisotropic restrictions exerted on the orientational and diffusional properties of the reagent molecules and in some cases also by preferential solubilities in structurally different regions inside the solution.Being interested in performing asymmetric transformations assisted either by chiral auxiliaries or by a chiral medium, we decided to study the effects that smectic phases of liquid-crystalline solvents composed of chiral molecules could exert on the stereochemical outcome of properly chosen reactions.The availability of chiral mesomorphic molecules exhibiting smectic phases is now increasing because of possible applications to the display industry. These materials can therefore be used also as solvents for organic reactions. We turned our search for asymmetric induction to smectic mesophases because our group recently demonstrated that S, liquid crystals provide the most efficient way to carry out quaternization reactions of aminobenzene sulphonate esters [ 121. We have demonstrated that S,

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Section: Methodsmentioning

confidence: 99%

Searching for asymmetric inductions in chiral smectic mesophases

Finzi¹,

Maccagnani²,

Masiero³

et al. 1989

Liquid Crystals

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“…S 2HNR 1 R 2 (17) (41) Ph , Thiolactams (46) are isolated on addition of carbon disulfide to cyclic nitrones (44); the products are formed in a sequence of [3 + 2] cycloaddition giving (45) …”

Section: Rl~net2mentioning

confidence: 99%

Synthesis of Thioamides and Thiolactams

Schaumann

1991

Comprehensive Organic Synthesis

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“…This latter reaction is a~a l o g o u s to a preparation of dithiobeiizoates from arvl dithiochloroformates and aromatic compounds (16).…”

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confidence: 99%

The Oxidation of Heterocyclic Thiones

Charlton¹,

Loosmore²,

McKinnon³

1974

Can. J. Chem.

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The treatment of a variety of heterocyclic thiones with hydrogen peroxide in acetic acid produces either heteroaromatic cations or the corresponding "oxo" compound. The results may be correlated with structural and electronic features. Benzo substitution or the presence of strongly electron withdrawing groups in the molecule favors the latter product, whereas the presence of a σ trivalent nitrogen atom in the molecule favors the former.

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Organische Schwefelverbindungen,97. Friedel‐Crafts‐Reaktionen mit Thiosäurechloriden

Cited by 35 publications

References 23 publications

Searching for asymmetric inductions in chiral smectic mesophases

Searching for asymmetric inductions in chiral smectic mesophases

Synthesis of Thioamides and Thiolactams

The Oxidation of Heterocyclic Thiones

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