Abstract In the development of plasmin inhibitors, a novel chemotype, pyrrolopyrimidine scaffold possessing two motifs, a hydantoin-containing P4 moiety and a warhead-containing P1 moiety, is uncovered. A unique feature of the new line of the plasmin inhibitors is that the interaction between the plasmin inhibitors and key subsites in plasmin can be controlled by a spacer like hydantoin. The application of the novel chemotype is demonstrated by 1n ...