5-(Hydroxyimino-methyl)-1H-pyrrole-2-carboxylic acid ethyl ester → Ethyl 5-cyano-1H-pyrrole-2-carboxylate

Temperature

140 °C

A solution of 5-(hydroxyimino-methyl)-1H-pyrrole-2-carboxylic acid ethyl ester (as prepared in the previous step) (500 mg, 2.75 mmol) in acetic anhydride (5 mL) was stirred at 140° C. for 2 h. The cooled mixture was quenched with ice and then dichloromethane was added and the mixture was made basic with solid sodium bicarbonate. The layers were separated, the organic layer was washed with saturated sodium bicarbonate (2×10 mL), water (2×10 mL), then dried over Na2SO4. The solvent was removed in vacuo to yield 260 mg (58%) of the title compound as a light brown crystalline solid. 1H-NMR (400 MHz, CDCl3): δ 10.45 (br s, 1H), 6.89 (m, 1H), 6.83 (m, 1H), 4.42 (q, 2H, J=7.2 Hz), 1.40 (t, 3H, J=7.1 Hz).

1. customThe cooled mixture was quenched with ice
2. additiondichloromethane was added
3. customThe layers were separated
4. washthe organic layer was washed with saturated sodium bicarbonate (2×10 mL), water (2×10 mL)
5. dry with materialdried over Na2SO4
6. customThe solvent was removed in vacuo

ORD record

ord-5b20ec5dcf10443ebf40a1b23801b292

Source dataset

uspto-grants-2008_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07427683B2