N-Acylureas in Peptide Synthesis: An X-Ray Diffraction and IR-Absorption Study

Autor:	Marco Crisma, Claudio Toniolo, Conrad H. Schneider, Jan Izdebski, V. Moretto, Jacek Pelka, Giovanni Valle
Rok vydání:	1990
Předmět:	chemistry.chemical_classification Hydrogen bond Stereochemistry Organic Chemistry Peptide Crystal structure Biochemistry Catalysis Amino acid Inorganic Chemistry chemistry.chemical_compound chemistry Drug Discovery Peptide synthesis Molecule Physical and Theoretical Chemistry Imide Carbodiimide
Zdroj:	Helvetica Chimica Acta. 73:626-634
ISSN:	1522-2675 0018-019X
Popis:	An X-ray diffraction analysts of two N-acyl derivatives of symmetrical dialkylureas, N-[Nα-(benzyloxycarbonyl)-L-valyl] -N, N′-diisopropylurea (1) and N-{Nα(tert-butyloxy)carbonyl -L-valyl}-N-N′-dicyclohexylurea (2), and one N-acyl derivative of an unsymmetrical N-N′-dialkylurea, N-[Nα-(benzyloxycarbonyl)-L-valyl] -N′-(tert-butyl)-N-ethylurea (3), has been performed. It was established that it is the least hindered O-acylisourca N-atom that attacks intramolecularly the carbonyl group of the Nα-protected amino acid activated by the unsymmetrical carbodiimide to form the major rearrangement product. The occurrence and nature of intra- and intermolecularly Hbonded forms of the N-acylureas in the crystal state were also assessed. It was also shown that soluble N-acylureas may compete with intermolecular (peptide)NH…OC(peptide) H-bonds in CH2Cl2.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::7d68b8aeab7ed9b9cb9e54d1196c53da https://doi.org/10.1002/hlca.19900730311 Zobrazit plný text záznamu Plný text