- Synthesis of dipeptides from N-hydroxy-3-azaspiro[5,5]undecane-2,4-dione activated α-amino acids
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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.
- Nowshuddin, Shaik,Ram Reddy
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scheme or table
p. 22 - 25
(2011/04/18)
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- Convenient synthesis of C-terminal di- and tri-peptide amides from N-protected dipeptidoylbenzotriazoles
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N-Protected dipeptidoylbenzotriazoles react with aqueous ammonia to give dipeptide primary amides (77-98%) and with N-unprotected α-amino amides to afford tripeptide primary amides (82-86%).
- Celik, Ilhami,Abdel-Fattah, Ashraf A.A.
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experimental part
p. 4923 - 4929
(2009/10/09)
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- The efficient preparation of di- and tripeptides by coupling N-(Cbz- or Fmoc-α-aminoacyl)benzotriazoles with unprotected amino acids
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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.
- Katritzky, Alan R.,Angrish, Parul,Suzuki, Kazuyuki
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p. 411 - 424
(2007/10/03)
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- N-(Cbz- and Fmoc-α-aminoacyl)benzotriazoles: Stable derivatives enabling peptide coupling of Tyr, Trp, Cys, Met, and Gln with free amino acids in aqueous media with complete retention of chirality
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Crystalline, chirally stable N-(Cbz- and Fmoc-α-aminoacyl) benzotriazoles 2a-f, activated derivatives of Tyr, Trp, Cys, Met and Gln undergo peptide coupling in aqueous media with unprotected L-Ala-OH and L-Phe-OH to give the chiral dipeptides in 70-98% yi
- Katritzky, Alan R.,Angrish, Parul,Huer, Deniz,Suzuki, Kazuyuki
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p. 397 - 402
(2007/10/03)
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