METHYL 6-OXO-4-PHENOXY-1-PHENYL-1,6-DIHYDRO-3-PYRIDAZINECARBOXYLATE synthesis

Yield:338405-06-4 72%

Reaction Conditions:

at 20; for 20 h;

Steps:

5.A

Step A. Preparation of methyl 6-oxo-4-phenoxy-1 -phenyl-1 ,6-dihyd- ropyridazine-3-carboxylate: A mixture of methyl 4-chloro-6-oxo-1 -phenyl-1 ,6- dihydropyridazine-3-carboxylate (Schober, B. D.; Megyeri, G.; Kappe, T. J. Heterocyclic Chem. 1990, 27, 471 ) (8.06 g, 30.4 mmol), sodium phenolate tri- hydrate (5.18 g, 30.4 mmol) and DMF (150 ml_) was stirred at room tempera- ture for 20 h. The solvent was evaporated in vacuo and the residue was parti- tionated between water (200 mL) and EtOAc (200 mL). The organic phase was separated and the aqueous phase was extracted with EtOAc (2 χ 100 mL). The combined organic extracts were washed successively with cold 3% NaOH (2 x 100 mL) and with cold water (2 χ 100 mL) and then were dried (Na₂SO₄) and evaporated in vacuo. Et₂O (50 mL) was added to the solid residue and the beige crystalline product (7.05 g, 72%) was filtered off and washed with Et₂O (50 mL).

References:

WO2012/120195,2012,A1 Location in patent:Page/Page column 59-60