Ethanol → 1-[2-(Chroman-3-yl)ethyl]-1,2,5,6-tetrahydropyridine-3-carboxylic acid ethyl ester

HRID 1032399Notes

Reaction equation

HRID 1032399 reaction equation
S(=O)(=O)(O)O.Cl.[CH3:7][O:8][C:9]([C:11]1[CH2:12][N:13]([CH2:17][CH2:18][CH:19]2[CH2:28][C:27]3[C:22](=[CH:23][CH:24]=[CH:25][CH:26]=3)[O:21][CH2:20]2)[CH2:14][CH2:15][CH:16]=1)=[O:10].[CH2:29](O)C>>[CH2:7]([O:8][C:9]([C:11]1[CH2:12][N:13]([CH2:17][CH2:18][CH:19]2[CH2:28][C:27]3[C:22](=[CH:23][CH:24]=[CH:25][CH:26]=3)[O:21][CH2:20]2)[CH2:14][CH2:15][CH:16]=1)=[O:10])[CH3:29]

Participants

4

Reactant 3

HCID 702EthanolHCID 1118Sulfuric AcidHCID 679071351-[2-(Chroman-3-yl)ethyl]-1,2,5,6-tetrahydropyridine-3-carboxylic acid methyl ester hydrochloride

Product 1

HCID 148384331-[2-(Chroman-3-yl)ethyl]-1,2,5,6-tetrahydropyridine-3-carboxylic acid ethyl esterYield 97.4%

Procedure

3.4 ml of sulphuric acid (100% strength) are added to a solution of 2.54 g (7.5 mmol) of 1-[2-(chroman-3-yl)ethyl]-1,2,5,6-tetrahydropyridine-3-carboxylic acid methyl ester hydrochloride in 170 ml of absolute ethanol and the whole is boiled under reflux for 35 hours. After cooling, the reaction mixture is concentrated by evaporation in vacuo. The residue is dissolved in water while cold and is extracted with diethyl ether. The aqueous phase is rendered alkaline, while cold, with sodium hydroxide solution (30% strength) and extracted with dichloromethane. The combined dichloromethane extracts are dried over sodium sulphate and concentrated by evaporation in vacuo. 2.30 g (97.4%) of 1-[2-(chroman-3-yl)ethyl]-1,2,5,6-tetrahydropyridine-3-carboxylic acid ethyl ester are obtained in the form of a yellow oil. The 1-[2-(chroman-3-yl)ethyl]-1,2,5,6-tetrahydropyridine-3-carboxylic acid ethyl ester hydrochloride produced therefrom using hydrochloric acid in diethyl ether crystallises from acetone/diethyl ether and melts at 177°-178°.

Workup

  1. temperatureunder reflux for 35 hours
  2. temperatureAfter cooling
  3. concentrationthe reaction mixture is concentrated by evaporation in vacuo
  4. dissolutionThe residue is dissolved in water while cold and
  5. extractionis extracted with diethyl ether
  6. extractionwhile cold, with sodium hydroxide solution (30% strength) and extracted with dichloromethane
  7. dry with materialThe combined dichloromethane extracts are dried over sodium sulphate
  8. concentrationconcentrated by evaporation in vacuo

Sources & evidence

ORD record
ord-dfd07072d9ec4470bf4be8aeaeabc3ff
Source dataset
uspto-grants-1990_09
Patent number
US04957928

Reaction notes

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