Methyl iodide → Lithium cyclohexylisopropylamide

HRID 1283671Notes

Reaction equation

HRID 1283671 reaction equation
[CH2:1]([Li:5])CCC.[CH:6]([NH:9][CH:10]1[CH2:15][CH2:14][CH2:13][CH2:12][CH2:11]1)([CH3:8])[CH3:7].[O:16]=[C:17]1[C:23]2[CH:24]=[CH:25][C:26]([CH2:28][C:29]([O:31][CH2:32][CH3:33])=[O:30])=[CH:27][C:22]=2[CH:21]=[CH:20][C:19]2[CH:34]=[CH:35][CH:36]=[CH:37][C:18]1=2.CI>CCOCC.O.O1CCCC1>[CH:6]([N-:9][CH:10]1[CH2:15][CH2:14][CH2:13][CH2:12][CH2:11]1)([CH3:8])[CH3:7].[Li+:5].[O:16]=[C:17]1[C:23]2[CH:24]=[CH:25][C:26]([CH:28]([CH3:1])[C:29]([O:31][CH2:32][CH3:33])=[O:30])=[CH:27][C:22]=2[CH:21]=[CH:20][C:19]2[CH:34]=[CH:35][CH:36]=[CH:37][C:18]1=2

Participants

9

Reactant 4

HCID 6328Methyl iodideHCID 62386CyclohexylisopropylamineHCID 53675848ethyl (5-oxo-5H-dibenzo[a,d]cyclohepten-2yl)acetateHCID 178418339Butyllithium

Product 2

HCID 10877271Lithium cyclohexylisopropylamideHCID 20310707ethyl 2-(5-oxo-5H-dibenzo[a,d]cyclohepten-2-yl)propionate

Reagents, catalysts & solvents 3

HCID 962WaterSolventHCID 3283Diethyl EtherSolventHCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
-80 °C

Procedure

Lithium isopropylcyclohexylamide is prepared by adding 10 mls. 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 dl 2-(5-oxo-5H-dibenzo[a,d]cyclohepten-2-yl)propionic acid (m.p. 138°-139°C, 113°-115°C). This mixture of optical isomers can exist in two crystalline forms. The form having the higher melting point is obtained by using chloroform/hexane as the recrystallizing solvent, while the form having the lower melting point is obtained by using acetone/hexane as the recrystallizing solvent.

Workup

  1. additionby adding 10 mls
  2. additionthere is added a solution of 2.94 g
  3. customto attain room temperature
  4. washThe ethereal layer is washed with dilute hydrochloric acid and water
  5. customdried
  6. customevaporated

Sources & evidence

ORD record
ord-195eeb3dfade479d9181cf4dafa7e27a
Source dataset
uspto-grants-1976_08
Patent number
US03975540

Reaction notes

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