3-benzylidenepentane-2,4-dione

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

Procedure: 3-Benzylidene-2,4-pentanedione (7, 6.50 g, 34.5 mmol) and palladium on activated carbon (0.25 g, 10%) were combined in ethyl acetate (50 ml). The mixture was placed under a hydrogen atmosphere (60 psi) on a Parr apparatus for 4 hr at room temperature. The resulting mixture was filtered through celite and the solvent evaporated to afford an oil. The crude oil was distilled bulb to bulb to give 6.52 g (99%) of a clear oil; 1H NMR: δ enol form: 2.02 (s, 6H), 3.62 (s, 2H), 7.24 (m, 5H); keto form: 2.07 (s, 6H), 3.11 (d, 2H, J=7.4 Hz), 4.01 (t, 1H, J=7.7 Hz), 7.24 (m, 5H); 13C NMR: δ 22.9, 29.4, 32.5, 33.8, 69.2, 107.9, 125.9, 126.3, 127.0, 128.1, 128.2, 137.7, 139.3, 191.4, 202.9. for 4 hr at room temperature The resulting mixture was filtered through celite the solvent evaporated to afford an oil The crude oil was distilled bulb to bulb

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

Procedure: 2,4-Pentanedione (2, 4.10 ml, 39.2 mmol) and benzaldehyde (1b, 4.06 ml, 40.0 mmol) were stirred in benzene (10 ml). Piperdine (3 drops) and glacial acetic acid (6 drops) were added and the mixture refluxed with a Dean-Stark water trap for 3 hr. The resulting mixture was cooled to room temperature, extracted into ethyl ether, washed with hydrochloric acid (1 N), saturated sodium bicarbonate, hydrochloric acid (1 N) and twice with water. The organic layer was dried over magnesium sulfate, filtered and evaporated to afford an oil. The crude oil was distilled bulb to bulb to give 7.03 g (95%) of a yellow oil; [expected mp 165-167° C.]; 1H NMR: δ 2.24 (s, 3H), 2.38 (s, 3H), 7.35 (s, 5H), 7.45 (s, 1H); 13C NMR: δ 26.5, 31.6, 128.9, 129.6, 130.5, 132.8, 139.6, 142.7, 196.2, 205.3. extracted into ethyl ether washed with hydrochloric acid (1 N), saturated sodium bicarbonate, hydrochloric acid (1 N) and twice with water The organic layer was dried over magnesium sulfate filtered evaporated to afford an oil The crude oil was distilled bulb to bulb

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

Procedure: To a solution containing 6.3 g of 3-benzyl-2,4-pentanedione in 50 ml of dichloromethane was gradually added 5.3 g of bromine in 20 ml of dichloromethane under cooling (0°-5° C.). The solution was stirred for 10 min. at 0° C. and the solvent evaporated in vacuo. The residue was dissolved in 100 ml of pyridine and refluxed for 30 min. Pyridine was evaporated in vacuo, the residue was dissolved in dichloromethane and washed first with 6M hydrochloric acid and then with 2.6M NaOH. The solvent was evaporated and the residue distilled in vacuo. Bp 186°-188° C./16 mm, yield 1.2 g. under cooling (0°-5° C.) the solvent evaporated in vacuo The residue was dissolved in 100 ml of pyridine refluxed for 30 min Pyridine was evaporated in vacuo the residue was dissolved in dichloromethane washed first with 6M hydrochloric acid The solvent was evaporated the residue distilled in vacuo

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

Procedure: 3-Benzylidene-2,4-pentanedione (7, 6.50 g, 34.5 mmol) and palladium on activated carbon (0.25 g, 10%) were combined in ethyl acetate (50 ml). The mixture was placed under a hydrogen atmosphere (60 psi) on a Parr apparatus for 4 hr at room temperature. The resulting mixture was filtered through celite and the solvent evaporated to afford an oil. The crude oil was distilled bulb to bulb to give 6.52 g (99%) of a clear oil; 1H NMR: δ enol form: 2.02 (s, 6H), 3.62 (s, 2H), 7.24 (m, 5H); keto form: 2.07 (s, 6H), 3.11 (d, 2H, J=7.4 Hz), 4.01 (t, 1H, J=7.7 Hz), 7.24 (m, 5H); 13C NMR: δ 22.9, 29.4, 32.5, 33.8, 69.2, 107.9, 125.9, 126.3, 127.0, 128.1, 128.2, 137.7, 139.3, 191.4, 202.9. for 4 hr at room temperature The resulting mixture was filtered through celite the solvent evaporated to afford an oil The crude oil was distilled bulb to bulb

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

Procedure: 2,4-Pentanedione (2, 4.10 ml, 39.2 mmol) and benzaldehyde (1b, 4.06 ml, 40.0 mmol) were stirred in benzene (10 ml). Piperdine (3 drops) and glacial acetic acid (6 drops) were added and the mixture refluxed with a Dean-Stark water trap for 3 hr. The resulting mixture was cooled to room temperature, extracted into ethyl ether, washed with hydrochloric acid (1 N), saturated sodium bicarbonate, hydrochloric acid (1 N) and twice with water. The organic layer was dried over magnesium sulfate, filtered and evaporated to afford an oil. The crude oil was distilled bulb to bulb to give 7.03 g (95%) of a yellow oil; [expected mp 165-167° C.]; 1H NMR: δ 2.24 (s, 3H), 2.38 (s, 3H), 7.35 (s, 5H), 7.45 (s, 1H); 13C NMR: δ 26.5, 31.6, 128.9, 129.6, 130.5, 132.8, 139.6, 142.7, 196.2, 205.3. extracted into ethyl ether washed with hydrochloric acid (1 N), saturated sodium bicarbonate, hydrochloric acid (1 N) and twice with water The organic layer was dried over magnesium sulfate filtered evaporated to afford an oil The crude oil was distilled bulb to bulb

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

Procedure: 3-Benzylidene-2,4-pentanedione (7, 6.50 g, 34.5 mmol) and palladium on activated carbon (0.25 g, 10%) were combined in ethyl acetate (50 ml). The mixture was placed under a hydrogen atmosphere (60 psi) on a Parr apparatus for 4 hr at room temperature. The resulting mixture was filtered through celite and the solvent evaporated to afford an oil. The crude oil was distilled bulb to bulb to give 6.52 g (99%) of a clear oil; 1H NMR: δ enol form: 2.02 (s, 6H), 3.62 (s, 2H), 7.24 (m, 5H); keto form: 2.07 (s, 6H), 3.11 (d, 2H, J=7.4 Hz), 4.01 (t, 1H, J=7.7 Hz), 7.24 (m, 5H); 13C NMR: δ 22.9, 29.4, 32.5, 33.8, 69.2, 107.9, 125.9, 126.3, 127.0, 128.1, 128.2, 137.7, 139.3, 191.4, 202.9. for 4 hr at room temperature The resulting mixture was filtered through celite the solvent evaporated to afford an oil The crude oil was distilled bulb to bulb

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

Procedure: 2,4-Pentanedione (2, 4.10 ml, 39.2 mmol) and benzaldehyde (1b, 4.06 ml, 40.0 mmol) were stirred in benzene (10 ml). Piperdine (3 drops) and glacial acetic acid (6 drops) were added and the mixture refluxed with a Dean-Stark water trap for 3 hr. The resulting mixture was cooled to room temperature, extracted into ethyl ether, washed with hydrochloric acid (1 N), saturated sodium bicarbonate, hydrochloric acid (1 N) and twice with water. The organic layer was dried over magnesium sulfate, filtered and evaporated to afford an oil. The crude oil was distilled bulb to bulb to give 7.03 g (95%) of a yellow oil; [expected mp 165-167° C.]; 1H NMR: δ 2.24 (s, 3H), 2.38 (s, 3H), 7.35 (s, 5H), 7.45 (s, 1H); 13C NMR: δ 26.5, 31.6, 128.9, 129.6, 130.5, 132.8, 139.6, 142.7, 196.2, 205.3. extracted into ethyl ether washed with hydrochloric acid (1 N), saturated sodium bicarbonate, hydrochloric acid (1 N) and twice with water The organic layer was dried over magnesium sulfate filtered evaporated to afford an oil The crude oil was distilled bulb to bulb