4-ethoxy-3-(1-methyl-7-oxo-3-propyl-6,7-dihydro-1H-pyrazolo[4,3-d]pyrimidin-5-yl)-N-(2-(1-methylpyrrolidin-2-yl)ethyl)benzenesulfonamide; 3-(6,7-Dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo[4,3-d]pyrimidin-5-yl)-4-ethoxy-N-[2-(1-methyl-2-pyrrolidinyl)ethyl]-benzenesulfonamide; 3-(4,7-Dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo[4,3-d]pyrimidin-5-yl)-4-ethoxy-N-[2-(1-methyl-2-pyrrolidinyl)ethyl]-benzenesulfonamide