Synthesis of cystamidin a (pyrrole-3-propanamide), a reported calpain inhibitor

The reported calpain inhibitor cystamidin A (1a, pyrrole-3-propanamide) and a regioisomer, pyrrole-2-propanamide (1b) have been synthesized from the corresponding pyrrolecarboxaldehydes. The previously assigned structure of cystamidin A is confirmed. However, neither synthetic cystamidin A nor regioisomer 1b inhibits recombinant human calpain I.