Incomplete TFA deprotection of N-terminal trityl-asparagine residue in fmoc solid-phase peptide chemistry.
We demonstrate that TFA deprotection of trityl-protected N-terminal asparagine is incomplete under normal conditions, resulting in low yields or impure products. This phenomenon does not occur if the asparagine is internal, nor for trityl-protected N-terminal glutamine. Studies on the deprotection of H Asn(Trt)OH show that the incomplete deprotection is due to the extremely slow removal of a trityl group close to an amino group. The use of the new methyl-trityl protecting group overcomes this problem resulting in rapid and complete deprotection.
Friede
M
M
Institut de Biologie Moléculaire et Cellulaire, Strasbourg, France.
Denery
S
S
Neimark
J
J
Kieffer
S
S
Gausepohl
H
H
Briand
J P
JP
D000588:Amines / Q000737:chemistry; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D001216:Asparagine / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D005449:Fluorenes / Q000737:chemistry; D008969:Molecular Sequence Data; D009584:Nitrogen / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D014269:Trifluoroacetic Acid / Q000737:chemistry*
D000588:Amines; D000596:Amino Acids; D005449:Fluorenes; C016456:N(alpha)-fluorenylmethyloxycarbonylamino acids; D010455:Peptides; D001216:Asparagine; D014269:Trifluoroacetic Acid; D009584:Nitrogen