Ketopimelic acid

Heat. When heated, succinic acid loses water and forms an internal anhydride with a stable ring stmcture. Dehydration starts at 170°C and becomes rapid at 190—210°C (25). Further heating of succinic anhydride causes decarboxylation and the formation of the dilactone of gamma ketopimelic acid (26) (eq. 1). The same reaction takes place at lower temperatures in the presence of alkaU. 

Succinic anhydride is stabilized against the deteriorative effects of heat by the addition of small amounts (0.5 wt %) of boric acid (27), the presence of which also decreases the formation of the dilactone of gamma ketopimelic acid (28). Compared with argon, CO2 has an inhibiting effect on the thermal decomposition of succinic acid, whereas air has an accelerating effect (29,30). 

The synthesis of pyrrolizidine developed by LukeS and Sorm31 and by Micheel and Flitsch32 starts with furylacrylic acid (56) which is converted by the Markwald reaction into y-ketopimelic acid (57). The carbonyl group in 57 is replaced by an amino group via the oxime or by the Leuckart-Wallach reaction this substitution results immediately in the formation of the lactam 58, which can be converted by heat into 3,5-dioxopyrrolizidine (59). The latter compound yields pyrrolizidine... 

Fig. 12. Seasonal changes in the relative abundances of (a) oxalic acid, (b) malonic acid, (c) succinic acid, (d) glutaric acid, (e) adipic acid, (f) azelaic acid, (g) 4-ketopimelic acid, (h) malic acid, (i) phthalic acid, and (j) maleic (hydroxysuccinic) acid in the total aerosol carbon (TC) in the aerosol samples from Jeju Island.

Ketopimelic Acid (Acetone-diacetic acid, hydrockelidonic Mid)... 

Palladium is a useful catalyst in several reactions which lead to keto-esters. p-Keto-esters react with allylic carbonates, with catalysis by palladium, in a decarboxylative allylation reaction. y-Keto-esters are prepared, in reasonable yield, by the palladium-catalysed regioselective oxidation of Py-unsaturated esters. y-Keto-esters are obtained in good yield by the palladium-catalysed Reformatsky reaction of ethyl bromoacetate and acid chlorides. Derivatives of y-ketopimelic acid are formed by the rhodium-carbonyl-catalysed reaction of derivatives of acrylic acid with carbon monoxide. A mild method for the conversion of propiolic esters into P-keto-esters via thiol addition has been reported (Scheme 63) it has been used in a formal synthesis of ( )-thienamycin. 

DIETHYL P-KETOPIMELATE (Pimelic acid, p-oxo-, diethyl ester)... 

The described method of preparing diethyl jS-ketopimelate is a modification of that described by Bouveault and is essentially the same as that reported by Bardhan and Nasipuri. This ester has also been prepared by condensation of 7-carbethoxybutyryl chloride with ethoxymagnesiummalonic ester and cleavage of the resulting acylated malonic ester by (3-naphthalenesulfonic add or by acetic or propionic acids containing a trace of concentrated sulfuric acid. ... 

IDegradation. Heating of succinic acid or anhydride yields y-ketopimelic dilactone, cyclohexane-1,4-dione, and a mixture of decomposition products that include acetic acid, propionic acid, acrylic acid, acetaldeide, acrolein, oxalic acid, cyclopentanone, and furane. In argon atmosphere, thermal degradation of succinic anhydride takes place at 340°C (123). Electrolysis of succinic acid produces ethylene and acetylene. 

Gardner and co-workers developed an efficient synthesis of pimelic acid (4) from furfural (1) involving conversion to furylacrylic acid (2) and esterification, which proceeds with cleavage of the ring and disproportionation to give diethyl y-ketopimelate (3). Huang-Minlon reduction by the usual procedure in diethylene... 

Ahpiperidine-2,6-dicarboxylate dehydrogenase (Q) N-succinyl-2-amino-6-ketopimelate synthase succinyl diaminopimelate aminotransferase succinyl diaminopimelate desuccinylase diaminopimelate epimerase diaminopimelate decarboxylase (Q threonine dehydratase (serine dehydratase) acetolactate synthase acetohydroxy acid isomeroreductase dihydroxy acid dehydratase valine aminotransferase a-isopropylmalate synthase isopropylmalate isomerase -isopropylmalate dehydrogenase leucine aminotransferase... 

Coned. H2S04 added, in very small portions at first, with manual stirring at —20 to 5° to diethyl a- (m-methoxyphenylethyl) -/ -ketopimelate, then allowed to warm to near room temp., and worked up, whereby the ester is hydrolized by refluxing 2.5 hrs. in aq. ale. KOH — y-(6-methoxy-2-carboxy-3,4-dihydro-l-naphthyl)-butyric acid. Crude Y 82%. (J. H. Hunter and J. Al Hogg, Am. Soc. 71, 1922 (1949).) s. a. 2, 795... 

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