ChemicalBook CAS DataBase List 3-Methyl-quinoxaline-2-carboxylic Acid

3-Methyl-quinoxaline-2-carboxylic Acid synthesis

10synthesis methods

Product Name:3-Methyl-quinoxaline-2-carboxylic Acid
CAS Number:74003-63-7
Molecular formula:C10H8N2O2
Molecular Weight:188.18

2-Quinoxalinecarboxylic acid, 3-Methyl-, Methyl ester

61522-54-1

74003-63-7

Methyl 3-methylquinoxaline-2-carboxylate (0.20 g, 0.99 mmol) was used as a raw material and dissolved in a solvent mixture of methanol (8 mL) and 2N sodium hydroxide solution (2 mL). The reaction mixture was stirred at room temperature for 30 min and then concentrated to about 1/3 of the original volume by rotary evaporator.Subsequently, the pH was adjusted to acidic with 1N hydrochloric acid solution and extracted with ethyl acetate. The organic phases were combined, washed sequentially with water and saturated saline, and dried over anhydrous magnesium sulfate. After filtration, the filtrate was concentrated by rotary evaporation to obtain a solid product, which was finally dried under high vacuum to give 3-methylquinoxaline-2-carboxylic acid (0.16 g, 87% yield).

61522-54-1
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74003-63-7
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Yield:74003-63-7 87%

Reaction Conditions:

Stage #1:2-Methylchinoxalin-3-carbonsaeuremethylester with sodium hydroxide;water in methanol for 0.5 h;
Stage #2: with hydrogenchloride in methanol;water

Steps:

5
3-Methyl-quinoxaline-2-carboxylic acid methyl ester (0.20 g, 0.99 mmol) was dissolved in methanol (8 mL) and 2 N sodium hydroxide (2 mL). The mixture was stirred for 30 minutes, then concentrated to about of its volume, acidified with 1 N hydrochloric acid and extracted with ethyl acetate. The combined extracts were washed with water and brine, dried over magnesium sulfate and concentrated to a solid which was dried on high vacuum (0.16 g, 87%).

References:

Pfizer Inc US2005/43292, 2005, A1 Location in patent:Page/Page column 12

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25519-55-5 Synthesis