A biogenic polyamine formed from spermidine. It is found in a wide variety of organisms and tissues and is an essential growth factor in some bacteria.

Methoxy-X04, a derivative of Congo red and Chrysamine-G, is a brain-permeable fluorescent probe for amyloid-β (Aβ).

hSMG-1 inhibitor 11e is a potent and selective hSMG-1 kinase inhibitor with an IC50 of 900-fold selectivity over mTOR (IC50 of 45 nM), PI3Kα/γ (IC50s of 61 nM and 92 nM) and CDK1/CDK2 (IC50s of 32 μM and 7.1 μM).