Methyl propiolate → Methyl 2-methyl-1H-imidazole-5-carboxylate

A solution of N′-hydroxyethanimidamide (65 g, 880 mmol) in anhydrous methanol (2 L) was treated with methyl propiolate (100 g, 1.19 mol), and the reaction was heated at reflux for 4 hours. The reaction mixture was concentrated in vacuo, and the residue was diluted with diphenyl ether (1 L) and heated at reflux for 4 hours. The hot solution was filtered, and the filtrate was cooled to room temperature and diluted with hexanes (2 L). The resulting solid was washed with diethyl ether (1 L), to afford the product as a brown solid. Yield: 60 g, 430 mmol, 49%.

1. temperaturethe reaction was heated
2. temperatureat reflux for 4 hours
3. concentrationThe reaction mixture was concentrated in vacuo
4. additionthe residue was diluted with diphenyl ether (1 L)
5. temperatureheated
6. temperatureat reflux for 4 hours
7. filtrationThe hot solution was filtered
8. additiondiluted with hexanes (2 L)
9. washThe resulting solid was washed with diethyl ether (1 L)

ORD record

ord-4f12d1943ccb4b989c1277e4e48e4d79

Source dataset

uspto-grants-2015_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08933224B2