A-aminopimelic acid

Following Scheme 4, L-a-aminosuberic acid can be obtained from iV-tosyI -L-gl utamic acid (5, n=2), upon protection of the a-carboxy and tosylamino groups as an oxazolidone 6, by extension of the side chain with the Amdt-Eistert method via the diazo ketone 7 by one methylene moiety in each cycle to produce in subsequent steps the L-a-aminoadipic acid [(5)-2-aminohexanedioic acid, 8, n = 2], L-a-aminopimelic acid [(5)-2-aminoheptanedioic acid, 8, n = 3] and finally L-a-aminosuberic acid [(5)-2-aminooctanedioic acid, 8, n = 4]J22 Treatment with HBr in AcOH was the method of choice for the acidolytic hydrolysis of the tosyl group. 23 ... 

Scheme 4 Synthesis of L-a-Aminosuberic Acid from A-Tosyl-i.-glutamic Acid (n = 2) via L-a-Aminoadipic (n = 3) and L-a-Aminopimelic Acid (n = 4) 22 ...

From the reaction product of ethyl cyclohexanone-2-carboxylate and hydrazoic acid, a-aminopimelic acid is obtained by hydrolysis. This is the sole product when concentrated sulfuric add is used as catalyst. 

If, however, traces of water are present in the reaction mixture and gaseous hydrogen chloride is the catalyst, the intermediate lactam hydrolyzes partially to a-aminopimelic acid which reacts further to yield dWysine. ... 

Berg, A.-M., and A.I. Virtanen Additional Notes on a-Aminopimelic Acid in Green Plants. Acta Chem. Scand. 8,1725 (1954). 

A number of syntheses of pyrrolizidine derivatives are based on cyclization of amino acids such as /3-(pyrrolidin-2-yl)propionic acid, 4-aminopimelic acid, and their homologues to give 3-oxo- and 3,5-dioxo-pyrrolizidines. Reduction of these cyclic amides leads to pyrrolizidines. 

The alkylation products are synthetically useful because simple subsequent transformations furnishes precursors of important natural products as illustrated in Scheme 8E.23. Simple oxidative cleavage of allylic phthalimide 45 generates protected (5)-2-aminopimelic acid, whose dipeptide derivatives have shown antibiotic activity. The esterification via deracemization protocol is not limited to the use of bulky pivalic acid. The alkylation with sterically less hindered propionic acid also occurs with high enantioselectivity to give allylic ester 116, which has been utilized as an intermediate towards the antitumor agent phyllanthocin and the insect sex excitant periplanone. Dihydroxylation of the enantiopure allylic sulfone gives diol 117 with complete diastereoselectivity. Upon further transformation, the structurally versatile y-hydroxy-a,(f-un-saturated sulfone 118 is readily obtained enantiomerically pure. 

Tetrahexylammonium phthalimide, generated in situ from potassium phthalimide and tetra-hcxylammonium bromide, aminates the racemic 3-(acyloxy)cycloalkenes 9 to imides (S)-10 with extremely high enantioselectivity in the presence of a palladium(0) complex prepared from dimeric n-allylpalladium chloride and the chiral ligand (/ ,/ )-G78. (5)-10c has been converted to a protected derivative of (S)-2-aminopimelic acid. 

Biosynthesis 2,3,4,5-Tetrahydropyridine, formed from aspartic acid and pyruvic acid, and succinyl-CoA are converted by A(-succinyl-2-amino-6-oxopimelic acid synthase to (V-succinyl-(25,65)-2,6-diaminopi-melic acid. Succinic acid is cleaved by succinyldi-aminopimelic acid desuccinylase (EC 3.5.1.18.) to furnish the (25,65) form of D. The meso-form is generated by D. epimerase. 

A role for a-keto-c-aminopimelic acid on the pathway of lysine syntheds is indicated by the discovery of a transaminase that acts on both diaminopimelic acid and on lysine 194). Cell suspendons of acetone-dried bacteria at pH 5 were able to transaminate all three stereoisomers of diaminopimelic acid and also d- and L-lysine in the presence of pyridoxal phosphate, with pyruvate, oxalacetate, and a-ketoglutarate serving as amino group acceptors. 

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