15545-10-5Relevant articles and documents
Deprotection of heteroaromatic carbamates via a base-catalyzed methanolysis
Shieh, Wen-Chung,Xue, Song,McKenna, Joe,Prasad, Kapa,Repi?, Oljan,Blacklock, Thomas
, p. 5645 - 5648 (2007/10/03)
A simple and mild method for the deprotection of heteroaromatic carbamates via methanolysis using a catalytic amount of base such as sodium methoxide, DBU, or Verkade's base (proazaphosphatranes) is presented. Carbamate protecting group of an aliphatic amine is not affected under these conditions.
A novel synthesis of N-methyl asparagine, arginine, histidine, and tryptophan
Aurelio, Luigi,Brownlee, Robert T. C.,Hughes, Andrew B.
, p. 3767 - 3769 (2007/10/03)
(graph presented) R = CH2(3-indolyl) tryptophan R = CH2CONH2 asparagine R = CH2(2-imidazolyl) histidine R = CH2CH2CH2(guanidyl) arginine N-Methyl amino acid residues in peptides
Protease-catalysed synthesis of peptides containing histidine and lysine
Beck-Piotraschke, Karin,Jakubke, Hans-Dieter
, p. 1505 - 1518 (2007/10/03)
The kinetically controlled α-chymotrypsin- and trypsin-catalysed syntheses of peptides starting from simple acyl donor esters containing histidine at the P1-position (nomenclature according to Schechter and Berger) and lysine derivatives as amino components were examined on the basis of their kinetic parameters. Despite higher specificity constants (k(cat)/K(M)) of trypsin-catalysed ester hydrolysis, α-chymotrypsin- catalysed acyl transfer to N(ε)unprotected lysine derivatives gave higher peptide yields as compared to trypsin-catalysed reactions, whereas in acyl transfer to N(ε)-protected lysine derivatives the trypsin-catalysed reaction gave higher yields. α-Chymotrypsin-catalysed acyl transfer reactions in frozen systems demonstrated the yield-enhancing effect of freezing. Using specific ester leaving groups, both the amount of enzyme and the reaction time can be reduced. In frozen systems the ε-amino function of H-Lys-OH acts as an acyl acceptor at pH ≤9.