6-Chloro-pyridazine-3-carboxylic acid ethyl ester synthesis
- Product Name:6-Chloro-pyridazine-3-carboxylic acid ethyl ester
- CAS Number:75680-92-1
- Molecular formula:C7H7ClN2O2
- Molecular Weight:186.6
63001-31-0
75680-92-1
Ethyl 3-pyridazinone-6-carboxylate (1.17 g, 6.96 mmol) was used as a raw material, which was dissolved in phosphoryl chloride (12 mL) and the reaction was heated at 100 °C for 2 hours. Upon completion of the reaction, the mixture was cooled to room temperature and subsequently concentrated under reduced pressure to about 3 mL. The concentrated residue was slowly poured into ice water and slowly neutralized with 10% aqueous sodium hydroxide solution under ice bath conditions. The neutralized mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution and subsequently dried with anhydrous magnesium sulfate. The dried organic phase was evaporated under reduced pressure to give the crude product. The crude product was purified by rapid chromatography on silica gel (200-300 mesh, eluent ratio hexane: ethyl acetate = 3:1) to afford ethyl 6-chloropyridazine 3-carboxylate (892 mg, yield 68.7%) as a white solid. The melting point was measured to be 145.6-146.7 °C (literature values 154-155 °C [56]).
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75680-92-1
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Yield: 150 mg (52%)
Reaction Conditions:
with 2-(Dimethylamino)pyridine in ethanol
Steps:
170.C Ethyl 3-chloropyridazine-6-carboxylate
The carboxylic acid (243 mg, 1.53 mmol) was dissolved in ~15 mL of ethanol and treated with 24 mg (0.2 mmol) of dimethylaminopyridine (DMAP) followed by 324 mg (1.69 mmol) 1-(3-dimethylaminopropyl-3-ethylcarbodiimide hydrochloride (EDCl). The reaction was stirred at ambient temperature for 4 hours and then worked up by the procedure described in Example 166A. The crude product was purified by flash chromatography on silica gel to give 150 mg (52%) of the title compound as a white crystalline solid. 1 H NMR (CDCl3, 300 MHz) δ 1.45 (t, 3H), 4.55 (q, 2H), 7.65 (d, 1H), 8.15 (d, 1H). MS (DCl/NH3) m/e 187/189 (M+H)+, 204/206 (M+H+NH3)+.
References:
Abbott Laboratories US5250548, 1993, A
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75680-92-1
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37972-69-3
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75680-92-1
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63001-31-0
85 suppliers
$65.00/100mg
75680-92-1
131 suppliers
$55.00/250mg
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75680-92-1
131 suppliers
$55.00/250mg