ethyl 1-bromocyclopentane-1-carboxylate

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

Procedure: DMF (a few drops) was added to a mixture of 1-bromocyclopentanecarboxylic acid (23.9 g, 124 mmol) and oxalyl chloride (11.6 mL, 130 mmol) in 250 mL of CH2Cl2. The mixture was stirred at ambient temperature for 2 h. After removing the low-boiling solvents in vacuo, ethanol (50 mL) was added to the residue followed by the addition of N,N-diisopropylethylamine (22.7 mL, 130 mmol). The mixture was stirred at ambient temperature for 20 min. After removing the low-boiling solvents in vacuo, the residue was partitioned between diethyl ether and water. The organic portion was washed with water and brine, and conc. in vacuo. The crude product was filtered through a plug of silica gel using 0 to 10% EtOAc in hexanes as the eluant. The title compound was obtained as a pale oil. After removing the low-boiling solvents in vacuo, ethanol (50 mL) was added to the residue The mixture was stirred at ambient temperature for 20 min After removing the low-boiling solvents in vacuo the residue was partitioned between diethyl ether and water The organic portion was washed with water and brine The crude product was filtered through a plug of silica gel using 0 to 10% EtOAc in hexanes as the eluant

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

Procedure: DMF (a few drops) was added to a mixture of 1-bromocyclopentanecarboxylic acid (23.9 g, 124 mmol) and oxalyl chloride (11.6 mL, 130 mmol) in 250 mL of CH2Cl2. The mixture was stirred at ambient temperature for 2 h. After removing the low-boiling solvents in vacuo, ethanol (50 mL) was added to the residue followed by the addition of N,N-diisopropylethylamine (22.7 mL, 130 mmol). The mixture was stirred at ambient temperature for 20 min. After removing the low-boiling solvents in vacuo, the residue was partitioned between diethyl ether and water. The organic portion was washed with water and brine, and conc. in vacuo. The crude product was filtered through a plug of silica gel using 0 to 10% EtOAc in hexanes as the eluant. The title compound was obtained as a pale oil. After removing the low-boiling solvents in vacuo, ethanol (50 mL) was added to the residue The mixture was stirred at ambient temperature for 20 min After removing the low-boiling solvents in vacuo the residue was partitioned between diethyl ether and water The organic portion was washed with water and brine The crude product was filtered through a plug of silica gel using 0 to 10% EtOAc in hexanes as the eluant

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

Procedure: A solution of 1-bromocyclopentanecarboxylic acid (5.1 g) in ethanol (40 ml) containing concentrated sulphuric acid (10 drops) was refluxed for 4 hours. The solvent was removed by evaporation and the residual oil was partitioned between ether (50 ml) and 2N sodium carbonate (30 ml). was refluxed for 4 hours The solvent was removed by evaporation the residual oil was partitioned between ether (50 ml) and 2N sodium carbonate (30 ml)

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

Procedure: Carrying out a reaction as described in Example 1, Step D, except that the 5,6-dichloro-9a-ethyl-7-hydroxy-1,2,9,9a-tetrahydro-3H-fluoren-3-one and ethyl bromoacetate are replaced by equimolar quantities of 5,6-dichloro-7-hydroxy-9a-methyl-1,2,9,9a-tetrahydro-3H-fluoren-3-one and ethyl 1-bromocyclopentane-1-carboxylate, there is obtained ethyl 1-[(5,6-dichloro-9a-methyl-3-oxo-1,2,9,9a-tetrahydro-3H-fluoren-7-yl)oxy]cyclopentane-1-carboxylate. Carrying out a reaction

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

Procedure: Carrying out a reaction as described in Example 1, Step D, except that the 5,6-dichloro-9a-ethyl-7-hydroxy-1,2,9,9a-tetrahydro-3H-fluoren-3-one and ethyl bromoacetate are replaced by equimolar quantities of 5,6-dichloro-7-hydroxy-9a-methyl-1,2,9,9a-tetrahydro-3H-fluoren-3-one and ethyl 1-bromocyclopentane-1-carboxylate, there is obtained ethyl 1-[(5,6-dichloro-9a-methyl-3-oxo-1,2,9,9a-tetrahydro-3H-fluoren-7-yl)oxy]cyclopentane-1-carboxylate. Carrying out a reaction

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

Procedure: DMF (a few drops) was added to a mixture of 1-bromocyclopentane-carboxylic acid (23.9 g, 124 mmol) and oxalyl chloride (11.6 mL, 130 mmol) in 250 mL of CH2Cl2. The mixture was stirred at ambient temperature for 2 h. After removing the low-boiling solvents in vacuo, ethanol (50 mL) was added to the residue followed by the addition of N,N-diisopropylethylamine (22.7 mL, 130 mmol). The mixture was stirred at ambient temperature for 20 min. After removing the low-boiling solvents in vacuo, the residue was partitioned between diethyl ether and water. The organic portion was washed with water and brine, and conc. in vacuo. The crude product was filtered through a plug of silica gel using 0 to 10% EtOAc in hexanes as the eluant. The title compound was obtained as a pale oil. After removing the low-boiling solvents in vacuo, ethanol (50 mL) was added to the residue The mixture was stirred at ambient temperature for 20 min After removing the low-boiling solvents in vacuo the residue was partitioned between diethyl ether and water The organic portion was washed with water and brine The crude product was filtered through a plug of silica gel using 0 to 10% EtOAc in hexanes as the eluant

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

Procedure: Carrying out a reaction as described in Example 1, Step D, except that the 5,6-dichloro-9a-ethyl-7-hydroxy-1,2,9,9a-tetrahydro-3H-fluoren-3-one and ethyl bromoacetate are replaced by equimolar quantities of 5,6-dichloro-7-hydroxy-9a-methyl-1,2,9,9a-tetrahydro-3H-fluoren-3-one and ethyl 1-bromocyclopentane-1-carboxylate, there is obtained ethyl 1-[(5,6-dichloro-9a-methyl-3-oxo-1,2,9,9a-tetrahydro-3H-fluoren-7-yl)oxy]cyclopentane-1-carboxylate. Carrying out a reaction

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

Procedure: Carrying out a reaction as described in Example 1, Step D, except that the 5,6-dichloro-9a-ethyl-7-hydroxy-1,2,9,9a-tetrahydro-3H-fluoren-3-one and ethyl bromoacetate are replaced by equimolar quantities of 5,6-dichloro-7-hydroxy-9a-methyl-1,2,9,9a-tetrahydro-3H-fluoren-3-one and ethyl 1-bromocyclopentane-1-carboxylate, there is obtained ethyl 1-[(5,6-dichloro-9a-methyl-3-oxo-1,2,9,9a-tetrahydro-3H-fluoren-7-yl)oxy]cyclopentane-1-carboxylate. Carrying out a reaction

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

Procedure: DMF (a few drops) was added to a mixture of 1-bromocyclopentane-carboxylic acid (23.9 g, 124 mmol) and oxalyl chloride (11.6 mL, 130 mmol) in 250 mL of CH2Cl2. The mixture was stirred at ambient temperature for 2 h. After removing the low-boiling solvents in vacuo, ethanol (50 mL) was added to the residue followed by the addition of N,N-diisopropylethylamine (22.7 mL, 130 mmol). The mixture was stirred at ambient temperature for 20 min. After removing the low-boiling solvents in vacuo, the residue was partitioned between diethyl ether and water. The organic portion was washed with water and brine, and conc. in vacuo. The crude product was filtered through a plug of silica gel using 0 to 10% EtOAc in hexanes as the eluant. The title compound was obtained as a pale oil. After removing the low-boiling solvents in vacuo, ethanol (50 mL) was added to the residue The mixture was stirred at ambient temperature for 20 min After removing the low-boiling solvents in vacuo the residue was partitioned between diethyl ether and water The organic portion was washed with water and brine The crude product was filtered through a plug of silica gel using 0 to 10% EtOAc in hexanes as the eluant

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

Procedure: DMF (a few drops) was added to a mixture of 1-bromocyclopentane-carboxylic acid (23.9 g, 124 mmol) and oxalyl chloride (11.6 mL, 130 mmol) in 250 mL of CH2Cl2. The mixture was stirred at ambient temperature for 2 h. After removing the low-boiling solvents in vacuo, ethanol (50 mL) was added to the residue followed by the addition of N,N-diisopropylethylamine (22.7 mL, 130 mmol). The mixture was stirred at ambient temperature for 20 min. After removing the low-boiling solvents in vacuo, the residue was partitioned between diethyl ether and water. The organic portion was washed with water and brine, and conc. in vacuo. The crude product was filtered through a plug of silica gel using 0 to 10% EtOAc in hexanes as the eluant. The title compound was obtained as a pale oil. After removing the low-boiling solvents in vacuo, ethanol (50 mL) was added to the residue The mixture was stirred at ambient temperature for 20 min After removing the low-boiling solvents in vacuo the residue was partitioned between diethyl ether and water The organic portion was washed with water and brine The crude product was filtered through a plug of silica gel using 0 to 10% EtOAc in hexanes as the eluant

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

Procedure: Carrying out a reaction as described in Example 1, Step D, except that the 5,6-dichloro-9a-ethyl-7-hydroxy-1,2,9,9a-tetrahydro-3H-fluoren-3-one and ethyl bromoacetate are replaced by equimolar quantities of 5,6-dichloro-7-hydroxy-9a-methyl-1,2,9,9a-tetrahydro-3H-fluoren-3-one and ethyl 1-bromocyclopentane-1-carboxylate, there is obtained ethyl 1-[(5,6-dichloro-9a-methyl-3-oxo-1,2,9,9a-tetrahydro-3H-fluoren-7-yl)oxy]cyclopentane-1-carboxylate. Carrying out a reaction

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

Procedure: Carrying out a reaction as described in Example 1, Step D, except that the 5,6-dichloro-9a-ethyl-7-hydroxy-1,2,9,9a-tetrahydro-3H-fluoren-3-one and ethyl bromoacetate are replaced by equimolar quantities of 5,6-dichloro-7-hydroxy-9a-methyl-1,2,9,9a-tetrahydro-3H-fluoren-3-one and ethyl 1-bromocyclopentane-1-carboxylate, there is obtained ethyl 1-[(5,6-dichloro-9a-methyl-3-oxo-1,2,9,9a-tetrahydro-3H-fluoren-7-yl)oxy]cyclopentane-1-carboxylate. Carrying out a reaction