Yield:28544-77-6 52%

Reaction Conditions:

with phosphorous (V) sulfide in pyridine at 20; for 3.08333 h;Heating / reflux;

Steps:

7

Preparation 7; 2H-Pyridazine-3 -thione; Combine 2H-pyridazin-3-one (5 g, 52 mmol) and phosphorous pentasulfide (4.6 g, 10.3 mmol) in pyridine (30 mL). Stir at room temperature for 5 min then reflux for 3 h. Cool to room temperature and concentrate in vacuo to give a dark green oil. Triturate the oil with water to give the title compound as dark green crystals (3.02 g, 52%).

References:

WO2007/28082,2007,A1 Location in patent:Page/Page column 64