Otto reaction

The synthetical experiments started by Openshaw and Robinson have for their immediate objective the preparation of one of the possible degradation products of strychnine, and a beginning has been made by the preparation of the lactam of hexahydrocarbazole-1 ll-/SjS -dipropionic acid (XXIV), which reproduces a portion of the strychnine molecule as represented in Robinson s formula (Ilia, p. 574), and in sulphuric acid gives a purple colour with a trace of potassium dichromate (Otto reaction). 

The material responsible for the colour in the classical Otto reaction on strychnine (Scheme 8), and other strychnine derivatives having the N(l)—C O grouping, has been isolated and assigned41 the dimeric, dicationic structure (27), both on spectrocopic grounds and on its reduction to 10,10 -bistrychnine. 

A very dilute solution of strychnine and its derivatives, containing the lactam grouping, Na-CO, in 80% sulfuric acid gives a reddish-violet to bluish-purple color (Otto reaction) on the addition of a trace of potassium dichromate solution. 

A particular kind of conjugate addition reaction earned the Nobel Prize in chemistry for Otto Diels and Kurt Alder of the University of Kiel (Germany) m 1950 The Diels-Alder reaction is the conjugate addition of an alkene to a diene Using 1 3 buta diene as a typical diene the Diels-Alder reaction may be represented by the general equation... 

The first triaryknethane dyes were synthesized on a strictiy empirical basis in the late 1850s an example is fuchsine, which was prepared from the reaction of vinyl chloride with aniline. Thek stmctural relationship to triphenylmethane was estabHshed by Otto and Fmil Fischer (5) with the identification of pararosaniline [569-61-9] as 4,4, 4 -triaminotriphenyknethane and the stmctural elucidation of fuchsine. Several different stmctures have been assigned to the triaryknethane dyes (6—8), but none accounts precisely for the observed spectral characteristics. The triaryknethane dyes are therefore generally considered to be resonance hybrids. However, for convenience, usually only one hybrid is indicated, as shown for crystal violet [548-62-9] Cl Basic Violet 3 (1), for which = 589 nm. 

Diels-Alder Reactions. The important dimerization between 1,3-dienes and a wide variety of dienoplules to produce cyclohexene derivatives was discovered in 1928 by Otto Diels and Kurt Alder. In 1950 they won the Nobel prize for their pioneering work. Butadiene has to be in the j -cis form in order to participate in these concerted reactions. Typical examples of reaction products from the reaction between butadiene and maleic anhydride (1), or cyclopentadiene (2), or itself (3), are <7 -1,2,3,6-tetrahydrophthaHc anhydride [27813-21 -4] 5-vinyl-2-norbomene [3048-64-4], and 4-vinyl-1-cyclohexene [100-40-3], respectively. 

All overview of the glycolytic pathway is presented in Figure 19.1. Most of the details of this pathway (the first metabolic pathway to be elucidated) were worked out in the first half of the 20th century by the German biochemists Otto Warburg, G. Embden, and O. Meyerhof. In fact, the sequence of reactions in Figure 19.1 is often referred to as the Embden-Meyerhof pathway. 

Alcohol can be detected h,v dislilJicig a few c.c. of Ihc sample with water, aud testing the distillate by the usual iodoform reaction. It the sample bo wHshed with warm waler in a separator, and the retractivu index of the washed otto l>c examined, it will be found to he higher than that ol the original otto. II this exoes.s be more (ban fl-Ofll i is almost certainly due to alcohol. 

At the end of 1938, Hahn sent her a description of his experiments on the interaction of neutrons with uranium. He and a young chemist. Fritz Strasstnan. had detennined that one of the reaction products was clearly barium. Meitner was so excited about this that she showed Hahn s letter to her nephew, physicist Otto Frisch. Their discussions on the topic gave birth to the idea of nuclear fission. 

In 1938, Lise Meitner, Otto Hahn, and Fritz Strassmann realized that, by bombarding heavy atoms such as uranium with neutrons, they could split the atoms into smaller fragments in fission reactions, releasing huge amounts of energy. We can estimate the energy that would be released by using Einstein s equation, as we did in Example 17.5. 

From 1928 when Otto Diels and Kurt Alder [1] made their extraordinary discovery until 1960 when Yates and Eaton [2] reported the acceleration of the Diels-Alder cycloadditions by Lewis acid catalysts, these reactions were essentially carried out under thermal conditions owing to the simplicity of the accomplishing thermal process. Since then a variety of methods have been developed to accelerate the reactions. The reaction between 1,3-butadiene and ethylene (Equation 2.1) is a typical example of a thermal Diels-Alder cycloaddition. 

Otto S., Engberts J. B. F. N. Diels-Alder Reactions in Water Pure Appl. Chem. 2000 72 1365-1372... 

Pindur U., Lutz G., Otto C. Acceleration and Selectivity Enhancement of Diels-Alder Reactions by Special and Catalytic Methods Chem. Rev. 1993 93 741 761... 

The reactions of ketenes with enamines are apparently not concerted but take place by the diionic mechanism Otto, P. Feiler, L.A. Huisgen, R. Angew. Chem. Int. Ed. Engl, 1968. 7, 737. 

Hydroformylation is the oldest and in production volume the largest homogeneously catalyzed industrial process. The hydroformylation reaction was discovered by Otto Roelen in 1938 the reaction is also called oxosynthesis and Roden s reaction [1-13]. 

Otto Diels and Kurt Alder won the Nobel Prize for Chemistry in 1950 for developing this reaction. 

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