1.2.3- Triones synthesis

The trisannulation reagent 7-acetoxy-l,l l-dodecadien-3-one (134) is derived from the bisannulation reagent 124 in four steps. This reagent is a synthetic equivalent of l-dodecene-3,7,11-trione, and the two ketone groups of the trione are masked as an acetoxy and a terminal alkene. The synthesis of optically active D-homo-19-norandrosta-4-en-3-one (135) by the trisannulation reaction... 

Another synthesis of pyrogaHol is hydrolysis of cyclohexane-l,2,3-trione-l,3-dioxime derived from cyclohexanone and sodium nitrite (16). The dehydrogenation of cyclohexane-1,2,3-triol over platinum-group metal catalysts has been reported (17) (see Platinum-GROUP metals). Other catalysts, such as nickel, rhenium, and silver, have also been claimed for this reaction (18). 

Barbituric acid — see also Pyrimidine-2,4,6-trione, perhydro-acidic pK, 3, 60 bromination, 3, 70 fluorination, 3, 70 structure, 3, 68 tautomerism, 2, 27 in thermography, 1, 392 Barbituric acid, iV-alkyl-chlorination, 3, 70 Barbituric acid, 5-aminomethylene-synthesis, 3, 524 Barbituric acid, 5-arylidene-pyridopyrimidines from, 3, 227 Barbituric acid, 1,3-dicyclohexyl-synthesis, 3, 113 Barbituric acid, 2-thio-sensitizing dye... 

PyrimidoX4,5-6]quinoline-2-carboxylic acids synthesis, 3, 224-225 Pyrimido[4,5-6]quinoline-2,4-diones synthesis, 3, 224 Pyrimido[5,4-6]quinolinediones synthesis, 3, 219 Pyrimido[4,5-6]quinolines synthesis, 3, 219, 224, 227, 228, 230, 231 Pyrimido[4,5-c]quinolines synthesis, 3, 224, 227 tautomerism, 3, 205 Pyrimido[5,4-6]quinolines synthesis, 3, 227 Pyrimido[5,4-c]quinolines synthesis, 3, 219, 224, 227, 230 Pyrimido[5,4-6]quinoline-1,3,5-trione, 7-chloro-synthesis, 3, 221... 

Several routes to 2,3-diketones have been reported. The most practical and general method is that of Ruzicka, Plattner and Furrer as adapted by Nace and Nelander for synthesis of the diosphenol corresponding to 5a-pregnane-2,3,20-trione (44) starting from 5a-pregnane-3,20-dione (40). The overall yield of diosphenol (44) by this route is 62% based on... 

In their general synthesis of quinoline-2,5,8(lf/)-triones, Avendano and coworkers use this modified protocol to access the key 2,5-dimethoxyanilide systems 11 required in their synthetic plan." For more examples, see reference 11 and references cited within. 

An acid-catalyzed substitution of a 6-oxo group on 2-aminopteridine-4,6-dione with hydrogen chloride in alcohols (65-100°, 3 hr, 80% yield) represents a convenient synthesis of the 6-alkoxy analogs. The reaction proceeds also with pteridine-2,4,6-trione and its 1-methyl and 1,3-dimethyl derivatives. While methoxylation of 2,4,7-trichloro-quinoline gives about equal amounts of 2- and 4-substitution, acid-catalyzed hydrolysis gives specific reaction at the 2-position only. ... 

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