Piperazic acid, All

Physovenine, K30 Phytol, T56 Phytostigmine, K30 Picraline, K12 Picraphylline, K9 Picrasin A, T53 Picromycin, Y25 Picrosalvin, T33 PicrotoXinin, T31 Piericidin A, Y30 Pillaromycin, Y28 Pillaronone, Y28 Pilocarpine, K30 Pimaricin, Y25 Pimaric acid, T32 Pinacolyl alcohol, A12 Pinacolylamine, A24 Pinenes, T8 Pinitol, A16 Pinidine, K19 Pinocampheol, T9 Pinocamphone, T9 /ran -pinocarveol, T9 Pinocarvone, T9 Pinonic acid, T8 Pinoresinol, Y7 Pipecolic acid, AlO Piperazic acid, All Piperidines, A5, AlO, All, A13, A26, A30, A34, K18-20, Y21, Y29, X4... 

Pinononic acid, T8 Pinoresinol, Y7 Pipecolic acid, AlO Piperazic acid. All... 

Cyclic lipopeptides containing piperazic acid show potent toxicity against tumor cells. This class of compounds shows potent antibacterial activity against gram-positive bacteria. The following five cyclic lipopeptides are all hexadepsipeptides and are produced by Streptomyces spp. 

Whatever the "real" reasons for this peculiar behavior, interesting papers centering on the synthesis of piz/A-piz containing natural products had appeared in the chemical literature by this time (1995), notably from the laboratories of U. Schmidt,but also of C. Shin and K. Hale. All these chemists had encountered serious difficulties during the acylation of unsaturated piperazic acids and their precursors. In particular, Schmidt had discovered that only N-Cbz-valinyl chloride is sufficiently reactive to acylate a terminally protected hydrazine very similar to 88. Furthermore, Olson and Rebert had determined earlier that serinylation of piperazic acids and of its precursors by any of the common methods fails. All we could do is to confirm this conclusion even cyclic A-carboxy anhydrides (NCA s) are impotent vis-a-vis 87-88. 

The proposed biosynthesis of piperazate residue of kutznerides, in analogy with monamycin and polyoxypeptin biosynthesis [213, 214], starts from the precursors glutamic acid and glutamine. The N—bond formation is achieved by the initial A-hydroxylation catalyzed by Ktzl, followed by the intramolecular displacement of the hydroxyl group by 5-amine as a nucleophile. The y,5-deidropiperazate is the common intermediate for all four piperazate moieties in kutznerides. Tautomerization of enamine to imine forms the -N unsaturated dehydropiperazate. Reduction of hydrazone leads to piperazate. The biosynthesis of y-chloro-substituted piperazate... 

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