ChemicalBook CAS DataBase List METHYL 4-OXO-4H-CHROMENE-2-CARBOXYLATE

METHYL 4-OXO-4H-CHROMENE-2-CARBOXYLATE synthesis

10synthesis methods

Product Name:METHYL 4-OXO-4H-CHROMENE-2-CARBOXYLATE
CAS Number:18398-73-7
Molecular formula:C11H8O4
Molecular Weight:204.18

67-56-1 Synthesis

67-56-1
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4940-39-0
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Yield:18398-73-7 91%

Reaction Conditions:

with sulfuric acid at 50; for 18 h;

Steps:

[0085] methyl 4-oxo-4H-chromene-2-carboxylate (5)

Chromone-2-carboxylic acid (45.0 g, 237 mmol) in methanol (700 mL) was treated with conc. sulfuric acid (5.4 mL) and warmed to 50 C. After 18 h, the mixture was cooled to room temperature, concentrated, transferred to a 2 L flask and diluted with EtOAc and satd. NaHCO3. The biphasic layer was stirred for 15 min and the layers were separated. The organic layer was washed with brine, dried (Na2SO4), filtered, and concentrated to give methyl 4-oxo-4H-chromene-2-carboxylate (5, 43.8 g, 91%) as a light yellow solid: 1H NMR (CDCl3, 300 MHz): δ 8.19 (dd, J = 8.0, 1.7 Hz, 1 H), 7.76-7.71 (m, 1 H), 7.59 (dd, J = 8.4, 0.7 Hz, 1 H), 7.47-7.42 (m, 1 H), 7.10 (s, 1 H), 4.00 (s, 3 H); HRMS (ESI+) m/z calcd for C11H9O4 [M+H] 205.0495, found 205.0493.

References:

WO2022/120048,2022,A1 Location in patent:Paragraph 0085