| abstract |
A (6aR, 9aS) -5,6a, 7,8,9,9a-hexahydro-5-methyl-3- (phenylamino) -2 is a potent and selective phosphodiesterase 1 (PDE1) inhibitor. -((4- (6-fluoropyridin-2-yl) phenyl) methyl) -cyclopent [4,5] imidazo [1,2-a] pyrazolo [4,3-e] pyrimidin-4 (2H) -one Providing a crystalline form of the free base. A free base crystal form of a compound having the formula: [Selection diagram] None |