Synthesis and structure- activity relationships of a novel and selective bone morphogenetic protein receptor (BMP) inhibitor derived from the pyrazolo[1.5-a] pyrimidine scaffold of Dorsomorphin: The discovery of ML347 as an ALK2 versus ALK3 selective MLPCN probe

A structure-activity relationship of the 3- and 6-positions of the pyrazolo[1,5-a] pyrimidine scaffold of the known BMP inhibitors dorsomorphin, 1, LDN-193189, 2, and DMH1, 3, led to the identification of a potent and selective compound for ALK2 versus ALK3. The potency contributions of several 3-position substituents were evaluated with subtle structural changes leading to significant changes in potency. From these studies, a novel 5-quinoline molecule was identified and designated an MLPCN probe molecule, ML347, which shows >300-fold selectivity for ALK2 and presents the community with a selective molecular probe for further biological evaluation. (C) 2013 Elsevier Ltd. All rights reserved.