Methyl chloroformate → Methyl 2-methylindolizine-3-carboxylate

HRID 502472Notes

Reaction equation

HRID 502472 reaction equation
[CH3:1][C:2]1[CH:3]=[C:4]2[N:9]([CH:10]=1)[CH:8]=[CH:7][CH:6]=[CH:5]2.Cl[C:12]([O:14][CH3:15])=[O:13]>>[CH3:1][C:2]1[CH:3]=[C:4]2[N:9]([C:10]=1[C:12]([O:14][CH3:15])=[O:13])[CH:8]=[CH:7][CH:6]=[CH:5]2

Participants

3

Reactant 2

HCID 6586Methyl chloroformate2×HCID 5826302-Methylindolizine

Product 1

HCID 13735249Methyl 2-methylindolizine-3-carboxylateYield 72.9%

Procedure

A mixture of 2-methylindolizine 1 (3.8 g, 29.0 mmol) and methyl chloroformate (22 g (18 ml), 231.6 mmol) was heated at reflux for 2 h. A further 12.2 g (10 ml) of methyl chloroformate were added, and the mixture was heated at reflux for 2 h. The reaction mixture was concentrated under vacuum and then purified by chromatography on a silica column (hexane/ethyl acetate 5:1, silica gel 200-425 mesh) to give 4 g of compound 2 (colorless oil). 1H NMR (CDCl3): δ 9.43 (d, J=7.1 Hz, 1H), 7.35 (d, J=8.8 Hz, 1H), 6.99-6.93 (m, 1H), 6.73-6.68 (m, 1H), 6.29 (s, 1H), 3.91 (s, 3H), 2.53 (s, 3H), 13C NMR (CDCl3): δ 162.7, 137.0, 134.6, 127.6, 121.8, 117.6, 111.8, 103.5, 103.48, 50.6, 15.1.

Workup

  1. temperaturewas heated
  2. temperatureat reflux for 2 h
  3. temperaturethe mixture was heated
  4. temperatureat reflux for 2 h
  5. concentrationThe reaction mixture was concentrated under vacuum
  6. custompurified by chromatography on a silica column (hexane/ethyl acetate 5:1, silica gel 200-425 mesh)

Sources & evidence

ORD record
ord-34a24e33bb1d4f9298e2ca68c035d1da
Source dataset
uspto-grants-2010_08
Patent number
US07776107B2

Reaction notes

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