820239-46-1Relevant academic research and scientific papers
Green, catalyst-free synthesis of mesalazine conjugates
Ibrahim, Mohamed A.,Panda, Siva S.,Alamry, Khalid A.,Katritzky, Alan R.
, p. 3255 - 3258 (2013/12/04)
A greener protocol for the synthesis of mesalazine conjugates is reported. Mesalazine conjugates are prepared in high yields by a one-pot reaction of mesalazine and aminoacyl/peptidoylbenzotriazoles in water under microwave irradiation. Georg Thieme Verlag Stuttgart New York.
Chemical ligation of S-scylated cysteine peptides to form native peptides via 5-, 11-, and 14-membered cyclic transition states
Katritzky, Alan R.,Tala, Srinivasa R.,Abo-Dya, Nader E.,Ibrahim, Tarek S.,El-Feky, Said A.,Gyanda, Kapil,Pandya, Keyur M.
experimental part, p. 85 - 96 (2011/04/12)
Cysteine-containing dipeptides 3a-l, (3b+3b′) (compound numbers in parentheses are used to indicate racemic mixtures; thus (3b+3b′) is the racemate of 3b and 3b′), and tripeptide 13 were synthesized in 68-96% yields by acylation of cysteine with N-(Pg-α-aminoacyl)- and N-(Pg-α-dipeptidoyl)benzotriazoles (where Pg stands for protecting group in the nomenclature for peptides throughout the paper) in the presence of Et3N. Cysteine-containing peptides 3a-l and 13 were S-acylated to give S-(Pg-α-aminoacyl)dipeptides 5a-l and S-(Pg-α-aminoacyl) tripeptide 14 without racemization in 47-90% yields using N-(Pg-α- aminoacyl)benzotriazoles 2 in CH3CN-H2O (7:3) in the presence of KHCO3. (In our peptide nomenclature, the prefixes di-, tri-, etc. refer to the number of amino acid residues in the main peptide chain; amino acid residues attached to sulfur are designated as S-acyl peptides. Thus we avoid use of the prefix "iso".) Selective S-acylations of serine peptide 3k and threonine peptide 3l containing free OH groups were thus achieved in 58% and 72% yield, respectively. S-(Pg-α-aminoacyl)cysteines 4a,b underwent native chemical ligations to form native dipeptides 3f,i via 5-membered cyclic transition states. Microwave irradiation of S-(Pg-α-aminoacyl)tripeptide 15 and S-(Pg-α-aminoacyl)tetrapeptide 17 in the presence of NaH2PO4/Na2HPO 4 buffer solution at pH 7.8 achieved chemical ligations, involving intramolecular migrations of acyl groups, via 11- and 14-membered cyclic transition states from the S-atom of a cysteine residue to a peptide terminal amino group to form native peptides 19 and 20 in isolated yields of 26% and 23%, respectively.
Convenient synthesis of C-terminal di- and tri-peptide amides from N-protected dipeptidoylbenzotriazoles
Celik, Ilhami,Abdel-Fattah, Ashraf A.A.
experimental part, p. 4923 - 4929 (2009/10/09)
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%).
Highly diastereoselective peptide chain extensions of unprotected amino acids with N-(Z-α-aminoacyl)benzotriazoles
Katritzky, Alan R.,Suzuki, Kazuyuki,Singh, Sandeep K.
, p. 2645 - 2652 (2007/10/03)
Coupling an unprotected amino acid or dipeptide in partially aqueous solution with a readily available N-(Z-α-amino-acyl)benzotriazole or N-(Z-α-aminopetidoyl)benzotriazole affords N-terminal-protected di-, tri-, and tetrapeptides in yields of 85-98% (average 95% for 2a-i, 93% for 4a-f and 4a′, 86% for 5a-b) with minimal epimerization.
