Diethyl-3-oxo-glutarate

To achieve type c aldolization, the monoprotected heptaketone (148) was prepared as shown in Scheme 6. ° Condensation of the dianion of 2,4-pentanedione with the ethylene ketal of diethyl 3-oxo-glutarate presumably affords (148). However, the substance eludes isolation or even spectral identification. Instead, naphthalene derivative (149) is obtained in 39% yield. Further aldolization, dehydration, and removal of the ethylene glycol moiety provides the naturally occurring anthrone (150). 

Fig. 11.2 Total ion current chromatogram (Varian MAT 44 GC-MS) of organic acids extracted using ethyl acetate and diethyl ether from the urine of a patient with propionic acidaemia and separated as their trimethylsilyl derivatives on a 25 m SE-54 WCOT capillary column using temperature programming from 70°C to 220°C at 4 C min Peak identifications are 1, lactate 2, 3-hydroxypropionate 3, 3-hydroxybutyrate 4, 2-methyl-3-hydroxybutyrate 5, 3-hydroxyisovalerate 6, 3-hydroxy- -valerate 7, aceto-acetate 8 and 9, 2-methyl-3-hydroxyvalerate 10, 3-oxovalerate 11, 2-methyl-3-oxo-valerate (isomer 1) 12,2-methylacetoacetate 13,2-methyl-3-oxovalerate (isomer 2) 14 propionylglycine 15, glutarate 16, adipate 17, 5-hydroxymethyl-2-furoate 18, 2-hydroxyglutarate 19,3-hydroxy-3-methylglutarate 20,4-hydroxyphenylacetate 21 and 22, methylcitrate 23,4-hydroxyphenyl-lactate 24, palmitate. (Redrawn with modifications from Truscott et al., 1979)...

---