Further applications of pentachlorophenyl active esters in lengthening peptide chains from C- and N-terminal amino acids using dicyclohexylamine C-protection
✍ Scribed by A. Kapoor; E. J. Davis; Mary J. Graetzer
- Publisher
- John Wiley and Sons
- Year
- 1968
- Tongue
- English
- Weight
- 615 KB
- Volume
- 57
- Category
- Article
- ISSN
- 0022-3549
No coin nor oath required. For personal study only.
✦ Synopsis
In order to eliminate the problems associated witb the use of alkali during peptide synthesis, a systematic investigation was catried out to lengthen pe tide chains by cou ling N-protected pentachlorophenyl active esters of a d n o acix and peptides w d amino acids and peptides, C-protected by dicydohrtrylamine. There was an appreciable iacrease in yields wheh N-protected pentachlorophenyl active esters of amino acid8 were coupled with di-and tripeptides instead of sin le amino acid units C-protected by dicyclohexylamine. From this, it was concludetthat peptide chains would be lengthened more profitably from C-terminal instead of N-terminal amino acid residues when the synthesis of eptides is carried out, using pentachbraphenyl active esters in combination with &cyclohexylamine Cmtectitm. l n addition t o affordin relatively better yields, this approach would further limit the degree of racemfdon 8s the active ester component used would alwayr be a monomer.
HE SYSTEMATIC SEARCH for suitable "acti-T vated" esters, for the synthesis of peptides v i a the aminolysis of esters started with the historic paper of Wieland and Bernhard, when they reported the synthesis of peptides uiu the phenyl thiolesters (1). For more than a decade varioas active esters have been used extensively in the synthesis of peptides and polypeptides with known sequence of amino acids (2-5). The pentachlorophenyl active esters, which were first reported in the literature in 1961 (B), afford an excellent method for lengthening the peptide chain. The pentachlorophenyl active esters have the following advantages: (a) they are one