Ethyl 11-bromoundecanoate

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

Procedure: 1000 g of 90% pure 11-bromoundecanoic acid (equivalent to 3.39 mol), 304.0 g (6.60 mol) of ethanol and 20.0 g of p-toluenesulfonic acid were introduced into 400 ml of chloroform in an experimental apparatus with water trap (for entrainers with higher specific gravity than water). The mixture was heated under reflux until water no longer separated out (about 6 hours). After the solution had cooled to room temperature it was washed successively with 1 l of water, 500 ml of saturated NaHCO3 solution and 1 l of water. The solvent was removed in vacuo. Vacuum distillation (b.p. 131-133° C./1 mbar) resulted in 716.3 g (2.44 mol, 72%) of ethyl 11-bromoundecanoate. The mixture was heated no longer separated out (about 6 hours) was washed successively with 1 l of water, 500 ml of saturated NaHCO3 solution and 1 l of water The solvent was removed in vacuo Vacuum distillation (b.p. 131-133° C./1 mbar)

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

Procedure: 1000 g of 90% pure 11-bromoundecanoic acid (equivalent to 3.39 mol), 304.0 g (6.60 mol) of ethanol and 20.0 g of p-toluenesulfonic acid were introduced into 400 ml of chloroform in an experimental apparatus with water trap (for entrainers with higher specific gravity than water). The mixture was heated under reflux until water no longer separated out (about 6 hours). After the solution had cooled to room temperature it was washed successively with 1 l of water, 500 ml of saturated NaHCO3 solution and 1 l of water. The solvent was removed in vacuo. Vacuum distillation (b.p. 131-133° C./1 mbar) resulted in 716.3 g (2.44 mol, 72%) of ethyl 11-bromoundecanoate. The mixture was heated no longer separated out (about 6 hours) was washed successively with 1 l of water, 500 ml of saturated NaHCO3 solution and 1 l of water The solvent was removed in vacuo Vacuum distillation (b.p. 131-133° C./1 mbar)

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

Procedure: Ethyl-11-bromoundecanoate (36.0 g, 123 mmol) and acetonitrile (200 ml) were placed in a flame-dried three-neck 500 ml round-bottomed flask equipped with a reflux condenser. Triphenyl phosphine (35.5 g, 135 mmol was added to the solution and the reaction mixture was refluxed for 36 hours under anhydrous conditions. After the reaction mixture had cooled, to room temperature, the acetonitrile was removed under reduced pressure. The crude product was triturated with ether. The solid was filtered and washed with ether to yield a pure compound 3, 11-carbethoxyundecyltriphenylphosphonium bromide (56.69 g, 83% yield). equipped with a reflux condenser the reaction mixture was refluxed for 36 hours under anhydrous conditions the acetonitrile was removed under reduced pressure The crude product was triturated with ether The solid was filtered washed with ether

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

Procedure: Compound 1, 11-Bromoundecanoic acid (41.38 g, 156 mmol), was placed in a 250 ml round-bottomed flask equipped with a reflux condenser. After absolute ethanol (60 ml) and concentrated HCl (1/2 ml) were added, the reaction mixture was refluxed overnight. The reaction mixture was allowed to cool to room temperature before the solvent was removed under reduced pressure. The resulting yellow oil was dissolved in ether. The ether solution was extracted with saturated NaHCO3 and H2O, and dried over MgSO4. The solvent was removed under reduced pressure. Purification of the crude product was obtained by vacuum distillation which yielded a colorless oil, ethyl-11-bromoundecanoate, compound 2 (37.32 g, 82.5% yield). equipped with a reflux condenser the reaction mixture was refluxed overnight was removed under reduced pressure The resulting yellow oil was dissolved in ether The ether solution was extracted with saturated NaHCO3 and H2O dried over MgSO4 The solvent was removed under reduced pressure Purification of the crude product was obtained by vacuum distillation which

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

Procedure: Compound 1, 11-Bromoundecanoic acid (41.38 g, 156 mmol), was placed in a 250 ml round-bottomed flask equipped with a reflux condenser. After absolute ethanol (60 ml) and concentrated HCl (1/2 ml) were added, the reaction mixture was refluxed overnight. The reaction mixture was allowed to cool to room temperature before the solvent was removed under reduced pressure. The resulting yellow oil was dissolved in ether. The ether solution was extracted with saturated NaHCO3 and H2O, and dried over MgSO4. The solvent was removed under reduced pressure. Purification of the crude product was obtained by vacuum distillation which yielded a colorless oil, ethyl-11-bromoundecanoate, compound 2 (37.32 g, 82.5% yield). equipped with a reflux condenser the reaction mixture was refluxed overnight was removed under reduced pressure The resulting yellow oil was dissolved in ether The ether solution was extracted with saturated NaHCO3 and H2O dried over MgSO4 The solvent was removed under reduced pressure Purification of the crude product was obtained by vacuum distillation which

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

Procedure: A mixture that consists of 54.1 g (100 mmol) of 2,3,4,6-tetra-O-benzyl-glucopyranose, 0.55 g (5 mmol) of tetramethylammonium chloride and 12.42 g (100 mmol) of DBN in 350 ml of diethoxymethane is cooled to 0° C. At 0° C., 44 g (150 mmol) of 11-bromoundecanoic acid-ethyl ester, dissolved in 50 ml of benzene, is added in drops over 30 minutes while being stirred vigorously. It is stirred for two hours at 20° C. 250 ml of methyl-tert-butyl ether is added, solid is filtered out, and the filtrate is evaporated to the dry state in a vacuum. The residue is taken up in 500 ml of ethanol/50 ml of water. 60 ml of 50% aqueous sodium hydroxide solution is added, and it is refluxed for five hours. It is cooled to 0° C., set at pH 8 with 10% aqueous hydrochloric acid, and then the solvent is distilled off (vacuum). The residue is taken up in 300 ml of water and 500 ml of dichloromethane, and the pH of the aqueous phase is set at 2 while being stirred (10% aqueous hydrochloric acid). The organic phase is separated, and the aqueous phase is extracted once more with 200 ml of dichloromethane. The combined organic phases are dried on magnesium sulfate, the solvent is distilled off in a vacuum, and the residue is chromatographed on silica gel (mobile solvent: dichloromethane/n-hexane/ethanol/acetic acid=20:5:3:0.5). The product-containing fractions are concentrated by evaporation, dissolved in 400 ml of ethyl acetate and shaken out three times with 200 ml of water. Then, the organic phase is separated and evaporated to the dry state in a vacuum. is added in drops over 30 minutes It is stirred for two hours at 20° C solid is filtered out the filtrate is evaporated to the dry state in a vacuum 60 ml of 50% aqueous sodium hydroxide solution is added it is refluxed for five hours It is cooled to 0° C. the solvent is distilled off (vacuum) while being stirred (10% aqueous hydrochloric acid) The organic phase is separated the aqueous phase is extracted once more with 200 ml of dichloromethane The combined organic phases are dried on magnesium sulfate the solvent is distilled off in a vacuum the residue is chromatographed on silica gel (mobile solvent: dichloromethane/n-hexane/ethanol/acetic acid=20:5:3:0.5) The product-containing fractions are concentrated by evaporation dissolved in 400 ml of ethyl acetate shaken out three times with 200 ml of water Then, the organic phase is separated evaporated to the dry state in a vacuum

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

Procedure: In this example, 12-(3-amino-2,4,6-triiodophenyl)dodecanoic acid is synthesized. 11-Bromoundecanoic acid (54.0 g, 200 mmol) was refluxed overnight with 150 ml absolute ethanol and a catalytic amount (1.0 ml) H2SO4. The solvent was removed in vacuo and the residue was dissolved in 100 ml CHCl3 and extracted with 100 ml H2O, twice with 100 ml 10% aq. NaHCO3, 100 ml water, and brine, and was dried with MgSO4Removal of the solvent in vacuo and distillation of the remaining yellow liquid under vacuum yielded ethyl-11-bromoundecanoate as a colorless liquid. The solvent was removed in vacuo the residue was dissolved in 100 ml CHCl3 extracted with 100 ml H2O, twice with 100 ml 10% aq. NaHCO3, 100 ml water, and brine was dried with MgSO4Removal of the solvent in vacuo and distillation of the remaining yellow liquid under vacuum

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

Procedure: In this example, 12-(3-amino-2,4,6-triiodophenyl)dodecanoic acid is synthesized. 11-Bromoundecanoic acid (54.0 g, 200 mmol) was refluxed overnight with 150 ml absolute ethanol and a catalytic amount (1.0 ml) H2SO4. The solvent was removed in vacuo and the residue was dissolved in 100 ml CHCl3 and extracted with 100 ml H2O, twice with 100 ml 10% aq. NaHCO3, 100 ml water, and brine, and was dried with MgSO4Removal of the solvent in vacuo and distillation of the remaining yellow liquid under vacuum yielded ethyl-11-bromoundecanoate as a colorless liquid. The solvent was removed in vacuo the residue was dissolved in 100 ml CHCl3 extracted with 100 ml H2O, twice with 100 ml 10% aq. NaHCO3, 100 ml water, and brine was dried with MgSO4Removal of the solvent in vacuo and distillation of the remaining yellow liquid under vacuum

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

Procedure: In a 5000 ml flask equipped with a stirrer and a condenser were charged 400.2 g of hydroquinone monobenzyl ether, 586.5 g of ethyl 11-bromoundecanoate, 331.7 g of anhydrous potassium carbonate, 33.2 g of potassium iodide and 1500 ml of N,N-dimethylformamide (DMF), and the mixture was refluxed for 6 hours. This solution was poured into 2000 ml of ice-water to precipitate white crystals. The precipitated crystals were collected by filtration, washed with distilled water and recrystallized from ethanol to obtain 535.5 g of the title compound. In a 5000 ml flask equipped with a stirrer and a condenser the mixture was refluxed for 6 hours to precipitate white crystals The precipitated crystals were collected by filtration washed with distilled water recrystallized from ethanol

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

Procedure: Ethyl-11-bromoundecanoate (36.0 g, 123 mmol) and acetonitrile (200 ml) were placed in a flame-dried three-neck 500 ml round-bottomed flask equipped with a reflux condenser. Triphenyl phosphine (35.5 g, 135 mmol) was added to the solution and the reaction mixture was refluxed for 36 hours under anhydrous conditions. After the reaction mixture had cooled to room temperature, the acetonitrile was removed under reduced pressure. The crude product was triturated with ether. The solid was filtered and washed with ether to yield a pure compound 3, 11-carbethoxyundecyltriphenylphosphonium bromide (56.69 g, 83% yield). equipped with a reflux condenser the reaction mixture was refluxed for 36 hours under anhydrous conditions the acetonitrile was removed under reduced pressure The crude product was triturated with ether The solid was filtered washed with ether

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

Procedure: Compound 1, 11-Bromoundecanoic acid (41.38 g, 156 mmol), was placed in a 250 ml round-bottomed flask equipped with a reflux condenser. After absolute ethanol (60 ml) and concentrated HCl (1/2 ml) were added, the reaction mixture was refluxed overnight. The reaction mixture was allowed to cool to room temperature before the solvent was removed under reduced pressure. The resulting yellow oil was dissolved in ether. The ether solution was extracted with saturated sodium carbonate (NaHCO3) and H2O, and dried over magnesium sulfate (MgSO4). The solvent was removed under reduced pressure. Purification of the crude product was obtained by vacuum distillation which yielded a colorless oil, ethyl-11-bromoundecanoate, compound 2 (37.32 g, 82.5% yield). equipped with a reflux condenser the reaction mixture was refluxed overnight was removed under reduced pressure The resulting yellow oil was dissolved in ether The ether solution was extracted with saturated sodium carbonate (NaHCO3) and H2O dried over magnesium sulfate (MgSO4) The solvent was removed under reduced pressure Purification of the crude product was obtained by vacuum distillation which

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

Procedure: Ethyl-11-bromoundecanoate (36.0 g, 123 mmol) and acetonitrile (200 ml) were placed in a flame-dried three-neck 500 ml round-bottomed flask equipped with a reflux condenser. Triphenyl phosphine (35.5 g, 135 mmol) was added to the solution and the reaction mixture was refluxed for 36 hours under anhydrous conditions. After the reaction mixture had cooled to room temperature, the acetonitrile was removed under reduced pressure. The crude product was triturated with ether. The solid was filtered and washed with ether to yield a pure compound 3, 11-carbethoxyundecyltriphenylphosphonium bromide (56.69 g, 83% yield). equipped with a reflux condenser the reaction mixture was refluxed for 36 hours under anhydrous conditions the acetonitrile was removed under reduced pressure The crude product was triturated with ether The solid was filtered washed with ether