A Cu-catalysed macrocyclisation was performed to obtain a macrocyclic coumarin-containing tripeptide for use in thrombin activity measurements.

1 Electronic Structure Calculations All electronic structure calculations were carried out with the ORCA program1. Density functional theory calculations on the BP862–6 (methanol and the tripeptide) and BLYP2–4,7 (only tripeptide) level of theory were performed using the def2-SVP basis8 set and the RI approximation with the def2-SVP/J auxilary basis set.9,10 B2PLYP11 computations (n-alkanes) us...

The same dialkylphosphite reagent can be used for both N protection and C activation of amino acids. Two N-diisopropyloxyphosphinyl (Dipp) tripeptide esters were prepared, and nine N-Dipp-dipeptide acids were synthesized through the activated amide intermediate. The positive ion FAB-MS of N-Dipp-tripeptide showed novel cleavage patterns in that only the N-phosphoryl fragment ions gave intense p...