Calcium Carbonate → (E)-methyl 4-methoxybut-2-enoate

A mixture of 54 g of methyl 4-bromocrotonate and 30.2 g of calcium carbonate in 200 mL of methanol was refluxed for 5 days. The mixture was filtered and the solvent was removed from the filtrate. The residue was dissolved in ether and washed with water containing a trace of hydrochloric acid. The ether solution was dried over magnesium sulfate. The solvent was removed and the residue was distilled to give 30.6 g of methyl 4-methoxycrotonate. This material was stirred in 170 mL of 1N sodium hydroxide for 3 min. The solution was washed with ether and the aqueous layer was acidified with sulfuric acid. The mixture was extracted several times with ether. The combined extracts were washed with brine and dried over magnesium sulfate. The solvent was removed to give 4-methoxycrotonic acid as a crystalline solid. A 10 g portion of this acid was stirred in 50 mL of benzene at 0° C. and 8.3 mL of oxalyl chloride was added. The mixture was stirred at room temperature for 6 hr. The solvent was removed and the residue was distilled to give 4-methoxycrotonyl chloride as a colorless liquid.

1. temperaturewas refluxed for 5 days
2. filtrationThe mixture was filtered
3. customthe solvent was removed from the filtrate
4. dissolutionThe residue was dissolved in ether
5. washwashed with water containing a trace of hydrochloric acid
6. dry with materialThe ether solution was dried over magnesium sulfate
7. customThe solvent was removed
8. distillationthe residue was distilled

ORD record

ord-fdf972afe92c4382b8832f1cec23f025

Source dataset

uspto-grants-2001_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06251912B1