Other Dicarbonyl Compounds

The heptodialdose 5 was synthesized from cycloheptatriene by osmylation of its iron tricarbonyl complex and ozonolysis. Addition of 1-ethoxyvinyl-lithium to the lactone 6 and subsequent acid hydrolysis has afforded Udeoxy-u-erythro-hex-2,3-diulose (7).  

Carbohydrate Chemistry, Volume 34 The Royal Society of Chemistry, 2003 

Crude enzyme extracts from the white rot fungus Oudemansiella mucida oxidized D-glucose to D-eryr/iro-hexos-2,3-diulose, and the diulose phosphonate 5 has been prepared from 2,3 5,6-di-C -isopropylidene-D-mannono-1,4-lactone.  

Moradei, C. du Mortier, A. Fernandez Cirelli and J. Thiem, J. Carbohydr. Chem., 1995,14, 525. 

Biomed Biotechnol, 1994,17 Chem. Abstr., 1995,122,240 188). 

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The use of triflic acid in the alkylation with other dicarbonyl compounds, such as isatins,258 parabanic acid,259 and ninhydrin,260 has also been explored. A significant acidity dependence was found in the reaction of isatin with benzene.258 Alkylation does not take place in the presence of trifluoroacetic acid (Ho = —2.7) at 25°C in 12 h. Adding 22% of triflic acid (//0 10.6) brings about a 90% yield of the 3,3-... 

Since diketones and other dicarbonyl compounds are easily made by enolate chemistry (Chapters 26-30) this strategy has been very popular and we will look at some detailed examples before moving tpn to more specialized reactions for the different classes of aromatic heterocycles. 

A number of patents describe the condensation of azulenes with squaric acid (257) or its equivalents and with other dicarbonyl compounds (or equivalents). TTius, azulenothiophene 45a (Scheme 63) yields symmetrical squarate betain 258 (86EAA187015) or (with 259) intermediate 260 and (after hydrolysis and reaction with 1,3,3-trimethyl-2-methyleneindole) unsymmetrical squarate 261 (89DEA3914151). Other examples are those of the two-step reactions of azulenothiophene 16 (Scheme 64) with glutaconedialdehyde or its cyclic equivalent 264 and another azulene to yield azulenium salts 263 and 266, respectively, presumably through intermediates 262 and 265 (90USA4965178). 

This Chapter contains material relevant to dialdoses, aldosuloses, diuloses, and other dicarbonyl compounds and their derivatives. Unsaturated members of the series are referred to in Chapter 12. 

Condensation of an amidine with a 1,3-diketone is a popular method for the direct preparation of the six-membered-ring pyrimidine. Numerous methods exist for the synthesis of the prerequisite diketone and other dicarbonyl compounds, making this a very attractive strategy for the preparation of substituted pyrimidines. 

Other dicarbonyl compounds such as quinones (Section 22.14) are reactive dienophiles. 

Sulphur compounds Diacetyl and other dicarbonyl compounds Furans,... 

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