title: Diastereoselective Synthesis of 5-Heteroaryl-Substituted Prolines Useful for Controlling Peptide-Bond Geometry.
abstract: A versatile diastereoselective Friedel-Crafts alkylation reaction of heteroaryl systems with a cyclic enecarbamate for the preparation of 5-heteroaryl-substituted proline analogues in good yields has been developed. These heterocyclic tethered cyclic amino acid building blocks constitute important structural motifs in many biologically active molecules. The impact of the substitution on proline cis/trans isomerization was explored by carrying out solution conformational studies by NMR on 5-furanyl-substituted proline-containing peptides. Conformational analysis revealed that the peptide bond is constrained in an exclusively trans conformation.
authors.forename: Rafat
authors.initials: R
authors.lastname: Ali
authors.affiliation: Academy of Scientific and Innovative Research , New Delhi 11000, India.
authors.forename: Gajendra
authors.initials: G
authors.lastname: Singh
authors.forename: Shalini
authors.initials: S
authors.lastname: Singh
authors.affiliation: Academy of Scientific and Innovative Research , New Delhi 11000, India.
authors.forename: Ravi Sankar
authors.initials: RS
authors.lastname: Ampapathi
authors.affiliation: Academy of Scientific and Innovative Research , New Delhi 11000, India.
authors.forename: Wahajul
authors.initials: W
authors.lastname: Haq