tert-butyl 2,2,2-trichloroethanimidate

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

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

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

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

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

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

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

Procedure: 10.0 g (about 90% pure, 62.4 mmol) of 6-oxoheptanoic acid were initially charged in 71.8 ml of cyclohexane, and 20.46 g (93.6 mmol) of tert-butyl 2,2,2-trichloroacetimidate and 15 ml of dichloromethane were added. At −10° C. 0.55 ml (6.24 mmol) of trifluoromethanesulfonic acid were slowly added dropwise to the solution. The resulting suspension was stirred overnight with warming to RT. The insoluble precipitate was then removed by filtration. The filtrate was washed twice with sodium bicarbonate solution and with saturated sodium chloride solution, dried over magnesium sulfate and concentrated under reduced pressure. The residue was purified by chromatography on silica gel (mobile phase cyclohexane/ethyl acetate 5:1). On standing overnight, a solid precipitated from the product obtained in this manner. This solid was removed by filtration with suction and discarded. The target product, obtained in the form of the filtrate, was not purified any further. This gave 4.51 g (36.1% of theory) of the title compound. At −10° C The insoluble precipitate was then removed by filtration The filtrate was washed twice with sodium bicarbonate solution and with saturated sodium chloride solution dried over magnesium sulfate concentrated under reduced pressure The residue was purified by chromatography on silica gel (mobile phase cyclohexane/ethyl acetate 5:1) On standing overnight a solid precipitated from the product obtained in this manner This solid was removed by filtration with suction The target product, obtained in the form of the filtrate was not purified any further

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

Procedure: To a suspension of N-Boc-4-iodo-(L)-phenylalanine (1.0 g, 2.56 mmol) in methylene chloride (7 mL) and cyclohexane (14 mL) were added t-butyl trichloroacetimidate (0.48 mL, 2.68 mmol) and boron trifluoride-etherate (48 μL). The reaction mixture was stirred for 5 hours at room temperature under a nitrogen atmosphere and then treated a second time with the same amounts of t-butyl trichloroacetimidate and boron trifluoride-etherate as above. After stirring overnight, a third addition was made, and the mixture was stirred a further 3 hours. The mixture was then filtered and the filtrate evaporated. The product was obtained pure by silica gel chromatography eluting with 10% diethyl ether in hexane; yield 650 mg. The product was treated with 1M HCl in ethyl acetate (7.3 mL) for 18 hours at room temperature. The mixture was evaporated and coevaporated several times with diethyl ether to afford the title compound; yield 522 mg. After stirring overnight a third addition the mixture was stirred a further 3 hours The mixture was then filtered the filtrate evaporated The product was obtained pure by silica gel chromatography eluting with 10% diethyl ether in hexane The product was treated with 1M HCl in ethyl acetate (7.3 mL) for 18 hours at room temperature The mixture was evaporated

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

Procedure: 5 mmol of 3-(1-triphenylmethyl-1H-imidazol-4-yl)propanol and 10 mmol of tert-butyl trichloroacetimidate are treated as described in Example 116. The title compound is crystallized in the form of the hydrogen maleate in ethanol and diethyl ether. The title compound is crystallized in the form of the hydrogen maleate in ethanol and diethyl ether

Conditions: temp:65.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2 mmol of 2-(1-triphenylmethyl-1H-imidazol-4-yl)ethanol and 4 mmol of tert-butyl trichloroacetimidate are dissolved in 4 ml of cyclohexane and 2 ml of dichloromethane. After the addition of 120 μl of boron trifluoride etherate, the solution is stirred at 60-70° C. for 18 hours. Filtration of the reaction mixture and evaporation of the solvent are followed by a detritylation in 2 ml of ethanol, 2 ml of acetone and 15 ml of 2N HCl at 70° C. The ethanol and acetone are removed under reduced pressure and triphenylmethanol is extracted with diethyl ether. The aqueous layer is alkalized with ammonia and extracted with diethyl ether. Evaporation of the solvent and final purification by column chromatography (eluent: dichloromethane/methanol, 90:10) yield the product in the form of an oil, which is crystallized in the form of the hydrogen oxalate in ethanol and diethyl ether. Filtration of the reaction mixture and evaporation of the solvent at 70° C The ethanol and acetone are removed under reduced pressure and triphenylmethanol is extracted with diethyl ether extracted with diethyl ether Evaporation of the solvent final purification by column chromatography (eluent: dichloromethane/methanol, 90:10) yield the product in the form of an oil, which is crystallized in the form of the hydrogen oxalate in ethanol and diethyl ether

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

Procedure: EX-654A) 3-Hydroxybenzaldehyde (4.08 g, 33.4 mmol) was slurried in 50 mL of anhydrous CH2Cl2 and added to t-butyl-2,2,2-trichloroacetimidate (25.0 g, 114 mmol) in 200 mL of anhydrous cyclohexane with an additional 50 mL of CH2Cl2 used in transfer. The mixture was stirred under nitrogen until uniform, then boron trifluoride diethyl etherate (0.50 mL, 4 mmol) was added via syringe and stirring was continued for 1 h. Powdered sodium bicarbonate (50 g, 0.6 mol) was added, and the solution was filtered through a silica gel plug, washing the plug with hexane. The solvent was evaporated to give crude product 3.54 g (59%) as an amber oil (85% pure by GC analysis). Chromatography on silica gel eluting with 0-10% ethyl acetate in hexane gave 1.88 g (32%) of pure 3-t-butoxybenzaldehyde product as a colorless oil. 1H NMR (C6D6) δ9.59 (s, 1H), 7.44 (br s, 1H), 7.20 (d t, 1H), 6.92 (m, 2H), 1.07 (s, 9H). stirring the solution was filtered through a silica gel plug washing the plug with hexane The solvent was evaporated to give crude product 3.54 g (59%) as an amber oil (85% pure by GC analysis)

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

Procedure: EX-654A) 3-Hydroxybenzaldehyde (4.08 g, 33.4 mmol) was slurried in 50 mL of anhydrous CH2Cl2 and added to t-butyl-2,2,2-trichloroacetimidate (25.0 g, 114 mmol) in 200 mL of anhydrous cyclohexane with an additional 50 mL of CH2Cl2 used in transfer. The mixture was stirred under nitrogen until uniform, then boron trifluoride diethyl etherate (0.50 mL, 4 mmol) was added via syringe and stirring was continued for 1 h. Powdered sodium bicarbonate (50 g, 0.6 mol) was added, and the solution was filtered through a silica gel plug, washing the plug with hexane. The solvent was evaporated to give crude product 3.54 g (59%) as an amber oil (85% pure by GC analysis). Chromatography on silica gel eluting with 0-10% ethyl acetate in hexane gave 1.88 g (32%) of pure 3-t-butoxybenzaldehyde product as a colorless oil. 1H NMR (C6D6) δ9.59 (s, 1H), 7.44 (br s, 1H), 7.20 (d t, 1H), 6.92 (m, 2H), 1.07 (s, 9H). stirring the solution was filtered through a silica gel plug washing the plug with hexane The solvent was evaporated to give crude product 3.54 g (59%) as an amber oil (85% pure by GC analysis)