17388-71-5Relevant articles and documents
Synthesis of dipeptides from N-hydroxy-3-azaspiro[5,5]undecane-2,4-dione activated α-amino acids
Nowshuddin, Shaik,Ram Reddy
scheme or table, p. 22 - 25 (2011/04/18)
A simple two step procedure for the synthesis of a dipeptide from N-hydroxy-3-azaspiro[5,5]undecane-2,4-dione (HO-ASUD) activated α-amino acids is described. In presence of DCC, N-hydroxy-3-azaspiro[5,5]undecane-2,4- dione readily esterifies the carboxylic acid group of all the N-protected amino acids to yield crystalline N-hydroxy-3-aza spiro[5,5]undecane-2,4-dione activated carboxy ester. The N-hydroxy-3-aza spiro[5,5]undecane-2,4-dione activated carboxy esters of N-protected amino acids readily condensed with other amino acids and gave a dipeptide. This new method is effective for the DCC coupling of a variety of chiral amino acids without loss of enantiomeric purity. Synthesis of fifteen dipeptides including the hitherto unreported Fmoc-l-Orn(Boc)-Val-OMe, Fmoc-l-Cys(trt)-Gly-OEt and Boc-l-Tyr-Gly-OEt is presented.
The efficient preparation of di- and tripeptides by coupling N-(Cbz- or Fmoc-α-aminoacyl)benzotriazoles with unprotected amino acids
Katritzky, Alan R.,Angrish, Parul,Suzuki, Kazuyuki
, p. 411 - 424 (2007/10/03)
N-(Cbz- or Fmoc-α-aminoacyl)benzotriazoles 2 and N-protected peptidoylbenzotriazoles 6 are coupled in aqueous acetonitrile solution with free amino acids or dipeptides to prepare: (i) 22 chirally pure dipeptides 5a-v (in an average yield of 82%) from N-(Cbz- or Fmoc-α-aminoacyl)benzotriazoles 2 and unprotected amino acids, (ii) five chiral tripeptides 7a-e (in an average yield of 75%) from N-protected peptidoylbenzotriazoles 6 and unprotected amino acids, (iii) one chiral tripeptide 7g (62%) from N-(Cbz- or Fmoc-α- aminoacyl)benzotriazole 2a and the free dipeptide 8. In all, N-(Cbz- or Fmoc-α-aminoacyl)benzotriazole derivatives of 17 of the 20 naturally occurring amino acids were used, including those containing the following unprotected side chain functionalities: alcoholic -OH (Ser), indole -NH (Trp), imidazole -NH, phenolic -OH (Tyr), -CONH2 (Gln, Asn), -SH (Cys), -CO2H (Glu, Asp), and -S-S (Cystine). Support for the complete retention of chirality was obtained by parallel experiments involving D-Ala, L-Ala, and DL-Ala for the preparation of di- and tripeptides. This and other evidence for chiral integrity was supported by NMR and HPLC analyses. Georg Thieme Verlag Stuttgart.