6398-06-7Relevant articles and documents
PROCESSES FOR PREPARATION OF (S)-TERT-BUTYL 4,5-DIAMINO-5-OXOPENTANOATE
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Paragraph 00321; 00322, (2019/03/12)
Provided are processes for the preparation of (S)-tert-butyl 4,5-diamino-5-oxopentanoate, or a salt, solvate, hydrate, enantiomer, mixture of enantiomers, or isotopologue thereof. Also provided are solid forms of various intermediates and products obtained from the processes.
Enzymatic C-terminal amidation of amino acids and peptides
Nuijens, Timo,Piva, Elena,Kruijtzer, John A.W.,Rijkers, Dirk T.S.,Liskamp, Rob M.J.,Quaedflieg, Peter J.L.M.
experimental part, p. 3777 - 3779 (2012/09/22)
Herein, we describe two versatile and high yielding enzymatic approaches for the conversion of semi-protected amino acid and peptidyl C-terminal α-carboxylic acids into their corresponding amides. In the first approach, the lipase Candida antarctica lipase-B (Cal-B), and in the second approach, the protease Subtilisin A, are used, respectively. We found that by using the ammonium salt of the α-carboxylic acid instead of separate ammonia sources, the enzymatic amidation reactions proceeded much faster without side reactions and gave near to quantitative yields of products.
Synthesis and anticonvulsant evaluation of a series of (R)- and (S)-N- Cbz-α-aminoglutarimide and succinimide
Park,Lee,Choi
, p. 1297 - 1302 (2007/10/03)
A series of (R)- and (S)-N-Cbz-α-aminoimides(1 and 2) were synthesized and were investigated their anticonvulsant activities in the MES and PTZ test, and determined the neurotoxicities. The most active compound among them was (S)-N-Cbz-α-amino-N-methyl glutarimide(1d) and the ED50 value in the MES test was 36.1 mg/kg and the ED50 value in the PTZ test was 12.5 mg/kg. In the rotorod test for neurotoxicity, the TD50 value was 62.5 mg/kg.
Electrochemical Decarboxylation of L-Threonine and Oligopeptide Derivatives with Formation of N-Acyl-N,O-acetals: Preparation of Oligopeptides with Amide or Phosphonate C-Terminus
Seebach, Dieter,Charczuk, Roland,Gerber, Christian,Renaud, Philippe,Berner, Heinz,Schneider, Helmut
, p. 401 - 425 (2007/10/02)
Derivatives of α-amino acids with two stereogenic centers (cf.L-threonine) and di-, tri- and tetrapeptides are electrolyzed in MeOH or AcOH, with formation of N-acyl-N,O-acetals (1b - 15b, 20b), in an anodic oxidative substitution of the COOH by an OR group.The amine ends of the oligopeptides may be benzyloxycarbonyl(Z)- or (tert-butoxy)carbonyl(Boc)-protected.With unprotected dipeptides, an electrolytic decarboxylative cyclization to imidazolidinones (18c, 19c) may also occur (in H2O/NH4OAc).The electrolyses are carried out in simple flasks with cooling jackets ('undivided cell'), using constant current conditions and anodes of Pt or glassy C.The electrolyte is generated in situ by adding 10 - 20 mol-percent of a tertiary amine.Mild acidic hydrolysis of electrolysis products thus obtained may lead to amino-acid amides or peptide amides (10c, 11c, 12c, 17c) with one amino acid less than the starting material.The N,O-acetals from L-threonine and the oligopeptides also react with organometallic nucleophiles such as Grignard compounds (->21 - 26, 29), with formation of products in which the original COOH group has been replaced by alkyl or allyl (sometimes even with moderate stereoselectivity).By treatment of the peptide-derived (open-chain) N,O-acetals with trialkyl or triaryl phosphites/TiCl4, the RO group is replaced by a phosphodiester group in a (non-diastereoselective) Michaelis-Arbuzov-type reaction (1d, 1e, 2d - 9d, 5e).Thus, the two-step sequence of electrolysis and phosphonation converts an oligopeptide derivative to an analogue with a phosphonic-acid end group.The diastereoisomeric N-protected dimethyl and diethyl dipeptidephosphonates (also prepared from the corresponding diaryl esters by Ti(OR)4-mediated transesterification) could be separated by preparative HPLC (SiO2, Lichrosorb Si 60, 10 μm); the dextrorotatory isomers of 1d - 3d were assigned L,D-, the laevorotatory ones L,L-configuration by hydrolysis to and identification of the known amino and aminophosphonic acids.The results described demonstrate a new simple route leading, from a give oligopeptide, to pure peptide analogues of known configuration.
Synthesis of the Dolastatin Thiazole Amino Acid Component (gln)Thz
Holzapfel, Cedric W.,Pettit, George R.
, p. 2323 - 2327 (2007/10/02)
The new thiazole amino acid (gln)Thz, found to occur as one unit of the marine sea hare cyclic pentapeptide dolastin 3, has been synthesized from L-glutamic acid by the route 2 -> 10e.The synthesis of Z-L-isoglutamine (4) was improved by selective ammonolysis of anhydride 3 at -60 deg C.A variety of reaction conditions were found to cause complete racemization during the Hantzsch thiazole synthesis step (9 -> 10).Deuterium labeling experiments indicated loss of the chiral center prior to formation of the thiazole system and suggested an imine-enamine type equilibration involving intermediates A B (Scheme II).The N-benzyloxycarbonyl derivative (10d) of (gln)Thz was partially resolved by employing brucine.
