Structural diversity of 1,3,4,6-tetracarbonyl compounds, their analogues and nitrogen containing derivatives (review)

The article summarizes published data and provides new information concerning the synthesis, structural diversity and properties of 1,3,4,6-tetracarbonyl compounds. Bis-1,3-diketonates are presented in solid state by (E,E)-isomer, and in solutions by dominant (E,E)- and minor (Z,Z)-isomers. Structure peculiarities and mass fragmentation of 1,6-dialkyl-3,4-dihydroxy-2,4-hexadiene-1,6-diones are investigated. Condensation of alkyl methyl ketones with diethyl oxalates and 1,2-diaminobenzene results in 2,3-Ais-(2-oxoalkylidene)tetrahydro-1,2,3,4-quinoxa-lines. With the help of spectral methods isomeric forms of synthesized compounds are found. Compounds containing contiguous 1,2- and 1,3-dioxo fragments look promising for fine organic synthesis and structural chemical analysis.