An approach is described to access 1,2,3‐triazole‐derived peptidyl vinyl
sulfones as Trypanosoma brucei brucei inhibitors by using click chemistry, starting
from a common azide intermediate. Among the triazole analogues, biotinylated inhibitors
11 and 12 offer possibilities as probes for the elucidation of target proteases
for this compound class. The development of two syntheses of a
1,2,3‐triazole‐based vinyl sulfone 5 are also presented. This compound
was accessed through a click reaction of a lysine‐derived azide (itself accessed by
diazo transfer), and a phenylalanine‐derived alkyne synthesised by both
Ohira–Bestmann and Corey–Fuchs‐based alkynylation protocols. Several
members of this family of compounds showed promising anti‐trypanosomal activity.
Unexpectedly, one of the most active compounds was allyl sulfone 24, which stems from
the isomerisation of vinyl sulfone 5, and is presumably a reversible inhibitor. A
docking study of the analogues in the active site of the parasitic cysteine protease rhodesain
was carried out in order to gain an insight into their likely interactions with these
enzymes.