Über Phenylsulfoxy‐essigsäure. (II.)

Pummerer, Rudolf

doi:10.1002/cber.19100430241

Cited by 162 publications

(30 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…[1,2] Mechanistically, Pummerer-type reactions are proposed to proceed via nucleophilic addition to an in situ generated thionium species to form sulfur containing motifs (Scheme 1a). Despite significant investigation of this transformation, there have been no reports to date describing catalytic enantioselective variants.…”

mentioning

confidence: 99%

Enantioselective Synthesis ofN,S‐Acetals by an Oxidative Pummerer‐Type Transformation using Phase‐Transfer Catalysis

et al. 2017

View full text Add to dashboard Cite

We report the first enantioselective oxidative Pummerer-type transformation using anionic phase-transfer catalysis, resulting in the formation of enantioenriched sulfur bearing heterocycles. This reaction includes the direct oxidation of sulfides to the thionium intermediate, followed by an asymmetric intramolecular nucleophilic addition to form the chiral cyclic N,S-acetals with moderate to high enantioselectivites. Deuterium labelling experiments were performed to identify the stereodiscrimination step of this process. Further analysis of the reaction transition states by means of multidimensional correlations and DFT computations highlight the existence of a set of weak noncovalent interactions between the catalyst and substrate that governed the enantioselectivity of the reaction.

show abstract

mentioning

confidence: 99%

Enantioselective Synthesis ofN,S‐Acetals by an Oxidative Pummerer‐Type Transformation using Phase‐Transfer Catalysis

et al. 2017

View full text Add to dashboard Cite

show abstract

“…87 The ease with which sulfoxides are reduced contrasts with the relative resistance of sulfones. The analogous "reductive acetoxylation" was reported 93 to take place when phenyl carbethoxymethyl sulfoxide was heated with acetic anhydride. Thus, besides the expected alkylation, there may be produced nuclear halogenations or oxidation of thiol or benzylamine groups.…”

Section: Chemical Properties Of Sulfoxidesmentioning

confidence: 65%

Chemistry of the Sulfoxide Group

Szmant

1961

Organic Sulfur Compounds

View full text Add to dashboard Cite

“…They can react with another acdiamine. This reaction is utilized commercially on a large scale in the synthesis of asymmetrical thioindigo and other dyes (9). A somewhat similar reaction mechanism has been described by Vittum and Duennebier (16), by which magenta azomethine dyes from pyrazolone and N,N-diethyl-p-phenylenediamine react with active pyrazolone couplers to form colorless bispyrazolone condensation products with regeneration of the p-phenylenediamine.…”

Section: R Rmentioning

confidence: 89%

Photographic Color-Forming Development Reaction

Schmidt¹,

Tulagin²,

Sprung³

et al. 1953

Ind. Eng. Chem.

View full text Add to dashboard Cite

amateur and professional photographers of today have THE available for use color films, in which three organic dyes are synthesized during the development of the conventional photographic silver image. The process was discovered by Fischer (6) in 1912 and was named by the inventor "the process of color-forming development."In the conventional photographic development process, the silver ion in the exposed light-sensitive silver halide is reduced to the silver atom and an image consisting of metallic silver is produced. This reduction is brought about by so-called developers, mostly organic aromatic hydroxy or amino compounds, such as hydroquinone, p-aminophenol, or p-phenylenediamine and their substitution products. During the reduction of the silver ions, the organic developing substance becomes oxidized.In the process of color-forming development, the oxidized form of a photographic developing substance is condensed with a second substance, an active coupler, to form a dye. The reaction can be represented by the equations given in Figure 1. Dye condensation takes place in situ and in direct proportion with the formation of the silver image. Color-forming development yields, therefore, a silver image intimately associated with a dye image. The silver image can be removed by standard bleaching processes, and pure dye images can be obtained.I n color photography, it has become accepted practice to use three suitably selected colors as primaries.Yellow. Green and red transmittant: blue absorbant: minus Magenta. Red and blue transmittant: green absorbant:Cyan. Blue and green transmittant: red absorbant: minus blue minus green red By mixing these primaries in various proportions, a complete range of colors can be matched in a manner satisfactory to the average human observer. Fischer has suggested, as couplers, three classes of colorless compounds which form the three essential primary colors with one common developing substance.In Figure 1 are shown examples of dye; obtainable by colorforming development. A single developing substance, N , Ndiethyl-p-phenylenediamine, is used in all three cases. With an open-chain ketomethylene compound, such as acetoacetanilide, a yellow dye results. A magenta dye is obtained from 1-phenyl-3-methyl-5-pyrasolone. The yellow and magenta dyes belong to the azomethine class. When a phenolic compound, such as l-hydroxy-2-naphthanilide, is used as the coupler, a cyan dye, which is of the quinoneimine class, is obtained.It was fortunate that Fischer was able to select a class of dyes, ax, bx, cx, which possessed characteristic absorption bands in the three principal regions of the visible spectrum and which could be obtained by the condensation of a single oxidized developer, z, with one of three colorless couplers, a, b, c.

show abstract

Über Phenylsulfoxy‐essigsäure. (II.)

Cited by 162 publications

References 12 publications

Enantioselective Synthesis ofN,S‐Acetals by an Oxidative Pummerer‐Type Transformation using Phase‐Transfer Catalysis

Enantioselective Synthesis ofN,S‐Acetals by an Oxidative Pummerer‐Type Transformation using Phase‐Transfer Catalysis

Chemistry of the Sulfoxide Group

Photographic Color-Forming Development Reaction

Contact Info

Product

Resources

About