Methyl iodide → Lithium cyclohexylisopropylamide

Participants

Reaction Conditions

Reaction Steps

Lithium isopropylcyclohexylamide is prepared by adding 10 mls. of 1.0 molar n-butyl lithium to a solution of 1.41 g. of isopropylcyclohexylamine in 100 ml. of dry tetrahydrofuran. To this solution, cooled to -80° C, there is added a solution of 2.94 g. of ethyl (5-oxo-5H-dibenzo[a,d]cyclohepten-2-yl)acetate (as prepared in Preparation 3 above) in 10 ml. of tetrahydrofuran. The mixture is left for 5 minutes, then 1.42 g. of methyl iodide is added. The reaction mixture is allowed to attain room temperature, then water and ether are added. The ethereal layer is washed with dilute hydrochloric acid and water, dried and evaporated to yield ethyl 2-(5-oxo-5H-dibenzo[a,d]cyclohepten-2-yl)propionate. This ethyl ester is refluxed for 12 hrs. in 5% aqueous potassium hydroxide, followed by acidification with dilute hydrochloric acid and ether extraction to afford 2-(5-oxo-5H-dibenzo[a,d]cyclohepten-2-yl)propionic acid.

Provenance & Evidence