Carbon Tetrachloride → Methyl 3-chloro-1H-pyrrole-2-carboxylate

Temperature

85 °C

5-Methyl-3,4-dihydro-2H-pyrrole (1.00 g, 12.0 mmol) was dissolved in carbon tetrachloride. To the solution was added NCS (12.85 g, 96 mmol) as a solid and reaction mixture heated to 85° C. and stirred overnight. The mixture was cooled to 0° C. and the precipitate filtered off and the solvent evaporated. The residue was dissolved in methanol and sodium methoxide (3.90 g, 72.2 mmol) was added. The resulting suspension was heated to reflux and stirred for 3 h. The methanol was evaporated and the residue suspended in Et2O. The solid was filtered off and the ether evaporated. The residue was dissolved in DCM and 2M HCl was added. The biphasic solution was stirred until no SM remained. The phases were separated and the organic layer was dried over MgSO4 and evaporated to an orange oil. The crude oil was adsorbed onto silica and run on 40 g of silica with EtOAc and Hexanes to afford the title compound as an orange solid (0.2958 g, 1.854 mmol, 15.41% yield). 1H NMR (400 MHz, CDCl3): δ ppm 9.54 (br. s., 1H), 6.80 (s., 1H), 6.17 (s., 1H), 3.83 (s, 3H). MS: m/z 160.0 (M+1).

1. additionTo the solution was added
2. temperatureThe mixture was cooled to 0° C.
3. filtrationthe precipitate filtered off
4. customthe solvent evaporated
5. dissolutionThe residue was dissolved in methanol
6. temperatureThe resulting suspension was heated
7. temperatureto reflux
8. stirringstirred for 3 h
9. customThe methanol was evaporated
10. filtrationThe solid was filtered off
11. customthe ether evaporated
12. dissolutionThe residue was dissolved in DCM
13. addition2M HCl was added
14. stirringThe biphasic solution was stirred until no SM
15. customThe phases were separated
16. dry with materialthe organic layer was dried over MgSO4
17. customevaporated to an orange oil

ORD record

ord-b1bca0eb0b4e455dab93fbd73301ad5f

Source dataset

uspto-grants-2012_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08304419B2