Quinone diazides synthesis

Quino[3,2-c][l,8]naphthyridine — see 4,5,12-Triazabenz[a]anthracenes Quinone, a-tocopheryl-synthesis, 3, 734 o-Quinone allides synthesis, 3, 741 o-Quinone diazides reactions... 

In the 1980 s three monographs were published that cover parts of the present book, namely Quinone Diazides, by Ershov, Nikiforov, and de Jonge (1981), Aromatic Diazo Compounds, by Saunders and Allen (1985), and Williams Nitrosa-tion (1988). The book of Saunders and Allen which is actually the third edition of Saunders original book (1936, 1949), focuses on synthesis and preparative methods. The other two books emphasize rather the mechanistic and physical organic aspects of their subjects. 

The general applicability of this type of synthesis of quinone diazides is nevertheless limited since, depending on the type and number of substituents in the 2-, 4-, and 6-positions of benzenediazonium ions, either hydroxy-de-diazoniation (reaction A in Scheme 2-20) or nucleophilic substitution of one of the groups in the 2-, 4-, or 6-position (reaction B) will predominate. It is difficult to predict the ratio of the two reactions in a specific case. This is exemplified by two investigations carried... 

Bis(diazo)-l,2,4,5-cyclohexanetetraone (4.5) may be regarded as a derivative of a double 1,2-quinone diazide. Its X-ray analysis was reported by Ansell (1969). The synthesis, properties, and structure of this interesting compound will be discussed in the forthcoming book on aliphatic diazo compounds (Zollinger, 1995, Secs. 2.3 and 5.2). 

Photo-de-diazoniation has found relatively little application in organic synthesis, as is clearly evident from the annual Specialist Periodical Reports on Photochemistry published by the Royal Society of Chemistry. Since the beginning of these reports (1970) they have contained a section on the elimination of nitrogen from diazo compounds, written since 1973 by Reid (1990). In the 1980s (including 1990), at least 90% of each report is concerned with dediazoniations of diazoalkanes and non-quinon-oid diazo ketones, the rest being mainly related to quinone diazides and only occasionally to arenediazonium salts. 

The reaction of carbenes 1, generated either thermally or photochemically from the corresponding quinone diazides 2, with pyridine results in the formation of the deeply colored betaines which can be isolated in substance from the reaction mixture.73,62 This alternative synthesis of the betaines opens a general route to pyridine ylides unsubstituted at the pyridine ring. 

The dediazoniation reaction is mainly dependent on the temperature, especially in the case of 4-aminophenol at low temperature 4-hydroxybenzenediazonium fluoride loses hydrogen fluoride to deliver a stable quinone-diazide which gives fluorophenol at 140°C only.93 The mechanisms involved in the synthesis of 4-fluorophenol are summarized in Scheme 5.93... 

The light-induced reaction of o-quinone diazides finds occasional use in the synthesis of a large number of compounds which are used in photography.273,277 Photolysis of diazoindauoues (CCVIII and CCX) provides a new synthetic route to cyclobutene carboxylic acid derivatives CCIX and CCXI, respectively.117 A good demonstration that ketenes are actually involved in the photodecomposition of o-quinone... 

Pyridine hydrohalides as reagents in heterocyclization 77KGS579. o-Quinone diazides, formation of condensed heterocycles from 80MI49. Radical cyclization in synthesis of hcterocycles 84YGK1121. 

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