ethyl 3-cyclopentylpropanoate

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:17.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 31.3 ml of a 2.8 M solution of EtMgCl in THF (87.7 mmol), diluted with 50 ml of anhydrous ether were placed into a 250 ml 4-neck round bottom flask, equipped with a mechanical stirrer and a reflux condenser. Upon cooling to 15-20° C., 6 g (35.16 mmol) of 3-cyclopentylpropionic acid ethyl ester (obtained according to Barret et al., J. Chem. Soc.; 1935, 1065) dissolved into 50 ml of anhydrous ether were added dropwise to the stirred solution at a rate which maintained the pot temperature between 15-25° C. The reaction mixture was then stirred at room temperature overnight and then quenched at 5° C. with the addition of 60 ml of water and neutralized at pH 7. The organic layer was separated and the ether and THF were stripped at reduced pressure. The resulting crude product was fractionally distilled with a bulb-to-bulb distillation (0.5 mbar, 120° C.) to give 4.5 g of pure 5-cyclopentyl-3-ethyl-3-pentanol (66% yield). were placed into a 250 ml 4-neck round bottom flask equipped with a mechanical stirrer and a reflux condenser were added dropwise to the stirred solution at a rate which maintained the pot temperature between 15-25° C quenched at 5° C. with the addition of 60 ml of water and neutralized at pH 7 The organic layer was separated The resulting crude product was fractionally distilled with a bulb-to-bulb distillation (0.5 mbar, 120° C.)

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 125 g. of dimethyl methylphosphonate were dissolved in 720 ml. of tetrahydrofuran and the solution cooled to -65°C. To this solution a solution of butyllithium [prepared from 150 g. of butyl bromide and 14.5 g. of lithium] in 550 ml. of diethyl ether was added dropwise. To the mixture a solution of 52.5 g. of ethyl 3-cyclopentylpropionate in 280 ml. of tetrahydrofuran was added drop-wise and the reaction mixture was stirred at the same temperature for 2 hours and afterwards at 0°C. overnight. The reaction mixture was then neutralised with acetic acid, concentrated under reduced pressure and the resulting residue after the addition of water was extracted with diethyl ether. The ethereal extract was dried over sodium sulphate, the solvent distilled off and the residue distilled under reduced pressure to obtain 47 g. (yield 61.2%) of the title compound as a colourless oil, b.p. 142°- 144°C./0.4 - 0.5 mm.Hg. NMR spectrum (tetrachloromethane): δ = 3.84 (6H, doublet), 3.19 (2H, doublet), 2.42 (2H, triplet), 2.0 - 1.09 (11H, multiplet). concentrated under reduced pressure the resulting residue after the addition of water was extracted with diethyl ether The ethereal extract was dried over sodium sulphate the solvent distilled off the residue distilled under reduced pressure to obtain 47 g

Conditions: temp:25.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 40.7 g of ethyl 3-cyclopentylpropionate are placed in 400 ml of DMF at from 0° to 5° C., 14.4 g of sodium hydride (80% in oil) are added. After dropwise addition of 200 ml of ethyl formate, the mixture is stirred at 25° C. for 24 h. The mixture is stirred into 1.6 l of 10% HCl, extracted with 800 ml of methylene chloride and distilled. 19.7 g (41%) are obtained of ethyl 2-formyl-3-cyclopentylpropionate of boiling point 117° C./12 min. are added extracted with 800 ml of methylene chloride distilled