6,8-DIMETHYL[1,2,4]TRIAZOLO[4,3-B]PYRIDAZINE synthesis

Yield:18591-75-8 87%

Reaction Conditions:

Stage #1: 4-amino-1,2,4-triazole;acetylacetonewith toluene-4-sulfonic acid in toluene; for 7 h;Heating / reflux;
Stage #2: with sodium hydrogencarbonate in chloroform;water;Product distribution / selectivity;

Steps:

1.B

Method B; 2,4-Pentanedione (6.0 g, 60 mmol) and p-toluene sulfonic acid (0.06 g, 0.35 mmol) were added to a solution of 4-amino-1 ,2,4-triazole (5 g, 60 mmol) in anhydrous toluene (25 mL) and heated at reflux for 7 h using a Dean Stark trap. Once the reaction was complete, the resulting yellow, transparent solution was allowed to cool to room temperature and evaporated to dryness. The crude oil was dissolved in CHCI₃ and washed with saturated NaHCO₃ aqueous solution. The organic layer was isolated, dried over anhydrous Na₂SO₄ and evaporated to dryness, yielding the pure product 1 (7.65 g, 87%) as light yellow crystals. ¹H NMR (CDCI₃, 300 MHz) δ: 2.54 (s, 3H), 2.70 (s, 3H), 6.81 .(S₁ 1 H), 8.98 (s, 1 H).

References:

WO2009/79683,2009,A1 Location in patent:Page/Page column 33