Michael chemistry

An example of the Michael chemistry, typical of all quinones bearing a replaceable hydrogen, is the preparation of a sulfone (6) (in 55% yield), which was ultimately converted to a polystyrene redox polymer (11). 

The retro-aldol-retro-Michael chemistry that we have developed in the context of fluorogenic substrates turned out to be of broad generality. In principle, any ionizable heteroatom-containing molecule maybe functionalized to become a substrate for 38C2-catalyzed reaction. 

In addition to the thia-Michael chemistry described previously that was successful in water, a range of metal-catalyzed approaches were devised that used organic solvents. These approaches are important if the substrate undergoes secondary reactions in the presence of water. One of the metal-catalyzed approaches used an NHC-supported iron catalyst to promote a thia-Michael addition (Schane 5.9) [10]. The organic solvent played a critical role in... 

The Michael chemistry, although sensitive to acid media, displays exceptional resistance characteristics when fully cured and has been utilised in applications which require extremely high chemictil resistance, such as external coatings for chemictil tankers. 

The Role of Degenerate States in Chemistry Advances in Chemical Physics, Volume 124. Edited by Michael Baer and Gert Due Billing. Series Editors T, Prigogine and Stuart A, Rice,... 

Michael Robb, Chemistry Department, King s College London, Strand London, United Kingdom... 

Addition Reactions. The addition of nucleophiles to quinones is often an acid-catalyzed, Michael-type reductive process (7,43,44). The addition of benzenethiol to 1,4-benzoquinone (2) was studied by A. Michael for a better understanding of valence in organic chemistry (45). The presence of the reduced product thiophenyUiydroquinone (52), the cross-oxidation product 2-thiophenyl-1,4-benzoquinone [18232-03-6] (53), and multiple-addition products such as 2,5-(bis(thiophenyl)-l,4-benzoquinone [17058-53-6] (54) and 2,6-bis(thiophenyl)-l,4-benzoquinone [121194-11-4] (55), is typical ofmany such transformations. 

The most extensive mechanistic studies of quinone Michael addition chemistry involve the arylsufinic acids, which yield reduced product (50,51). The sulfones produced in such reactions have been examined electrochemicaHy (48) and kineticaHy (52). The influence of substitutents in the quinone has... 

Nucleophilic Substitution Reactions. Many of the transformations reali2ed through Michael additions to quiaones can also be achieved usiag nucleophilic substitution chemistry. In some iastances the stereoselectivity can be markedly improved ia this fashion (100), eg, ia the reaction of ben2enethiol with esters (R = CH C O) and ethers (R = 3) 1,4-naphthoquiaones. 2-Bromo-5-acetyloxy-l,4-naphthoquiQone [77189-69-6J, R = Br, yields 75% of 2-thiophenyl-5-acetyloxy-l,4-naphthoquinone [71700-93-1], R = SC H. 3-Bromo-5-methoxy-1,4-naphthoquinone [69833-10-9], R = Br, yields 82% of 3-thiophenyl-5-methoxy-l,4-naphthoquinone [112740-62-2] R = SC H. ... 

A number of BMI resias based on this chemistry became commercially available through Rhc ne Poulenc for appHcation ia priated circuit boards and mol ding compounds and Rhc ne Poulenc recognized the potential of bismaleimides as building blocks for temperature-resistant thermoset systems. The basic chemistry, however, was not new, because the Michael addition reaction had been employed by Du Pont to obtain elastomeric reaction products from bismaleimides and Hquid polymeric organic diamines (15). 

Probably the first to take up this technique for purposes of scientific research was Michael Polanyi (1891-1976) who in 1922-1923, with the metallurgist Erich Schmid (1896-1983) and the polymer scientist-to-be Hermann Mark (1895-1992), studied the plastic deformation of metal crystals, at the Institute of Fibre Chemistry in Berlin-Dahlem in those days, good scientists often earned striking freedom to follow their instincts where they led, irrespective of their nominal specialisms or the stated objective of their place of work. In a splendid autobiographical account of those... 

A. S. Michaels Simplified Method of Interpreting Kinetic Data in Fixed-Bed Ion Exchange, Industrial and Engineering Chemistry, 44(8) 1922 (1952). 

Density-Functional Methods in Chemistry and Materials Science Edited by Michael Springborg Published 1997, ISBN 0 471 96759 9... 

Rowland Pettit (1927-19811 was born in Port Lincoln, Australia. He received two doctoral degrees, one from the University of Adelaide in 1952 and the second from the University of London in 1956, working with Michael Dewar. He then became professor of chemistry at the University of Texas, Austin (1957-1981). 

ArthuT Michael (1853—19421 was born to a wealthy family in Buffalo, New York. Although he received no formal university degrees, he studied in Heidelberg, Berlin, and the Ecole de Medecine, Paris. Returning to the United States, he became professor of chemistry at Tufts University (1882—1889. 

In addition to enolate ions, other kinds of carbon nucleophiles also add to a jjS-iinsaturated acceptors in Michael-like reactions. Among the most important such nucleophiles, particularly in biological chemistry, are enamines, which are... 

The preparation of 5-ACETYL-l,2,3,4,5-PENTAMETHYLCYCLO-PENTADIENE is of value in the synthesis of pentamethyleyclo-pentadiene and many pentamethylcyclopentadienyl metal carbonyl derivatives that are more soluble in organic solvents than those derived from cyclopentadiene. Simple preparations of 5,6-DIHYDRO-2-PYRAN-2-0NE and 2-//-PYRAN-2-ONE make these hitherto rather inaccessible intermediates available for cycloaddition and other reactions. The already broad scope of the Michael reaction has been widened further by including an efficient preparation of ETHYL (E)-3-NITROACRYLATE. Workers in the field of heterocyclic chemistry will find a simplified method for the preparation of 2,3,4,5-TETRA-HYDROPYRIDINE of help. 

Prof. Dr. Michael J. S. Dewar Department of Chemistry, The University of Texas Austin, TX 78712, USA... 

NEW Green chemistry promotes environmentally sound chemistry. Passages in the text created in consultation with Michael Cann and new end-of-chapter exercises are accompanied by a (IT). Topics include ionic liquids (Chapter 5), supercritical C02 (Chapter 8), yttrium in paint (Chapter 12), chelates as a substitute for chlorine bleach (Chapter 16), and transesterification (Chapter 19). 

Some contributed in substantial ways. Roy Tasker, University of Western Sydney, contributed to the Web site for this book, designed related animations, and selected the icons for the animation media links. Michael Cann, University of Scranton, opened our eyes to the world of green chemistry in a way that has greatly enriched this book... 

Brook, Adrian, G., and Brook, Michael, A., The Chemistry of Silenes. 

Peter Warneck. Chemistry of the Natural Atmosphere. 1988 S. Pal Arya. Introduction to Micrometeorology. 1988 Michael C. Kelley. The Earth s Ionosphere. 1989 William R. Cotton and Richard A. Anthes. Storm and Cloud Dynamics. 1989... 

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