propan-2-yl benzoate

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

Procedure: CAUTION—The reaction and workup should be conducted in a good fume hood. A mixture of isopropyl benzoate (8.13 ml, 50 mmol), P4S10 (7.40 grams, 16.7 mmol), HMDO (17.7 mL, 83.3 mmol), and xylene (50 mL, dried over 3A molecular sieves) was mechanically stirred and refluxed under argon for 8 hours. The reaction mixture was cooled in an ice-bath and treated with aqueous K2CO3 solution (21 mL of 5.3 M, 111 mmol). Acetone (25 mL) was added and the mixture was stirred vigorously for 30 minutes in the ice-bath. Water and benzene were then added, the layers separated, and the aqueous phase extracted with benzene. The combined organic phase was washed with dilute K2CO3 solution, water and brine, and dried over anhydrous Na2SO4. Evaporation of the solvent and distillation of the residue through a short Vigreaux column gave 7.46 grams (83%) of isopropyl thionobenzoate, bp 54–61° C./0.01 mm:1H NMR CDCl3) δ1.52 (d,J=6.6 Hz, 6H), 5.94(heptuplet, j-6.6 Hz, 1H)), 7.41 (m,2H), 7.55 (m,1H), 8.23 (m,2H); 13C NMR (CDCl3) δ21.32, 75.60, 128.05, 128.85, 132.59, 139.00, 210.68. Analysis by gas chromatography showed 98.3% purity, with 1.5% of the starting ester as the major impurity. CAUTION—The reaction and workup refluxed under argon for 8 hours The reaction mixture was cooled in an ice-bath the layers separated the aqueous phase extracted with benzene The combined organic phase was washed with dilute K2CO3 solution, water and brine dried over anhydrous Na2SO4 Evaporation of the solvent and distillation of the residue through a short Vigreaux column

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

Procedure: A mixture of Example 9E (200 mg, 0.5 mmol), ethyl 3-(piperidin-4-yl)benzoate (125 mg, 0.56 mmol) in dichloroethane (20 mL) was added titanium(IV) isopropoxide (0.6 ml, 2.03 mmol) at room temperature. The mixture was stirred at room temperature for 12 hours. Sodium borohydride (96.7 mg, 2.54 mmol) and methanol (1 mL) were added to the reaction mixture and stirred for another 2 hours. LC-MS indicated that the reaction was complete. Aqueous Sodium bicarbonate (20 mL) was added to the reaction mixture. The reaction mixture was extracted with dichloromethane (3×30 mL). The organic fractions were dried with sodium sulfate, filtered, and concentrated. The residue was purified by chromatography (eluent: 20 to 80% ethylacetate in petroleum ether) on silica to give a mixture of the title compound and isopropyl benzoate. stirred for another 2 hours The reaction mixture was extracted with dichloromethane (3×30 mL) The organic fractions were dried with sodium sulfate filtered concentrated The residue was purified by chromatography (eluent: 20 to 80% ethylacetate in petroleum ether) on silica to give