5-(2-Ethoxyphenyl)-1,6-dihydro-1-Methyl-3-propyl-7H-pyrazolo[4,3-d]pyriMidine-7-thione synthesis

Yield:479074-06-1 72%

Reaction Conditions:

with pyridine;diphosphorus pentasulfide in toluene; for 6 h;Reflux;

Steps:

4 Example 4 Preparation of 2-(2-ethoxy)-phenyl-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazolo [4,3-d] pyrim idine-7-thione

Example 4 Preparation of 2-(2-ethoxy)-phenyl-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazolo [4,3-d] pyrim idine-7-thione [0027] [0028] 2-(2-ethoxy)-phenyl-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyri midine-7-one (50g (0.16mol)), phosphorus pentasulfide (17.8g (0.08mol)), pyridine (250ml)were added into a 500ml three-neck flask with a mechanical stirrer, stirred, heated and refluxed for 6 hours, TLC tracing was performed until the reactants were totally disappeared. The solvent pyridine was removed by distilling under reduced pressure, concentrated ammonia water ((25-28%) 75ml)and ethanol 300ml were added, heated and refluxed for 30 min. It was cooled, filtered, dried, and crude product (45g)was obtained. The crude product was heated and solved into chloroform (150ml), activated carbon (5g)was added, stirring and reflux was performed for 30 min, it was filtered and the filtrate was washed with saturated brine and water consequently and dried with magnesium sulfate anhydrous, chloroform was removed by distilling, the obtained solid was re-crystallized with ethanol and dried, solid (38g)was obtained with a yield of 72%

References:

EP2666776,2013,A1 Location in patent:Paragraph 0027; 0028