The present invention provides heterocyclic derivatives which activate the IP receptor. Activating the IP receptor signaling pathway is useful to treat many forms of PAH, pulmonary fibrosis and exert beneficial effects in fibrotic conditions of various organs in animal models and in patients. Pharmaceutical compositions comprising such derivatives are also encompassed. Examples of compounds of the invention include the compounds according to Formula Ia, or a pharmaceutically acceptable salt thereof, and the compounds of the examples.
A ruthenium-catalysed annulative transfer hydrogenation strategy, enabling straightforwardaccess to tetrahydron fused-pyrazine derivatives from N-heteroaryl diamines and vicinal diols, has been demonstrated for the first time. Such a synthesis proceeds...