Hydrochloric Acid → Cyclopentanecarboxylic acid, 1-methyl-, methyl ester

Beteiligte Stoffe

Reaktionsschritte

To a stirred solution of diisopropylamine (3.95 g, 39.0 mmol) in dry THF (50 ml) at -78° C. under an atmosphere of nitrogen was added n- butyllithium (2.5M, 11.7 ml, 29.3 mmol). The mixture was stirred for 10 minutes before methyl cyclopentanecarboxylate (Aldrich) (2.5 g, 19.5 mmol) was added dropwise. Stirring was continued for a further 10 minutes before methyl iodide (8.31 g, 58.5 mmol) was added dropwise. The reaction mixture was stirred at -78° C. for a further 1 hour before being allowed to warm up to room temperature and being stirred for a further 1 hour. The reaction mixture was poured onto an admixture of water and ether (1:1, 100 ml) and acidified with dilute hydrochloric acid (2M). The aqueous solution was separated and extracted further with ether (3×25 ml) and the combined ether layers were washed with water (2×50 ml), saturated sodium chloride solution (50 ml) and dried over MgSO4. Filtration and evaporation of solvent under reduced pressure yielded methyl 1-methylcyclopentanecarboxylate as a colourless oil (2.38 g, b.p. 106° C. at 10 mmHg[Kugelrohr]).

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