ethyl 3-amino-6-chloropyridazine-4-carboxylate synthesis

Yield:1161847-32-0 99%

Reaction Conditions:

with ammonia;triethylamine in 1,4-dioxane at 100; for 48 h;

Steps:

8

Example 8.; A sealed tube was charged with 3,6-dichloro-pyridazine-4-carboxylic acid ethyl ester (4.37 g, 19.8 mmol), 80 mL of dioxane and triethylamine (5.6 mL, 40 mmol). Ammonia was rapidly bubbled in via a dipersion tube for 2 minutes. The tube was capped and the yellow solution was stirred at 100 ⁰C for 2 d, then allowed to cool. The mixture was transferred to a flask, using diethyl ether in rinsings, and concentrated to a yellow solid. The solid was partitioned between 100 mL of water and 100 mL of ethyl acetate. The aqueous layer was extracted with two 100 mL portions of ethyl acetate. There initially is undissolved solid in the aqueous layer that eventually disappears with the ethyl acetate extractions. The combined organic layers were concentrated to 3.93 g (99% crude) of 3- amino-6-chloro-pyridazine-4-carboxylic acid ethyl ester as a yellow solid that was used without further purification.

References:

WO2009/77334,2009,A1 Location in patent:Page/Page column 84