ethyl 4-acetyl-5-oxohexanoate

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

Procedure: Dissolve ethyl 4-acetyl-5-oxohexanoate (2.00 g, 9.99 mmol) in acetic acid (21 mL). Add methyl hydrazine (589 μL, 10.99 mmol) and stir at room temperature for 18 hr. Concentrate and dissolve residue in ethyl acetate. Wash ethyl acetate layer with saturated aqueous sodium bicarbonate solution. Extract aqueous layer twice with ethyl acetate, dry (magnesium sulfate), filter, concentrate and purify (silica gel chromatography, eluting with 0:100 to 100% ethyl acetate:hexanes) to give 3-(1,3,5-trimethyl-1H-pyrazol-4-yl)-propionic acid ethyl ester (1.95 g, 93%). MS (ES): m/z=211 [M+H]+. Concentrate dissolve residue in ethyl acetate Extract aqueous layer twice with ethyl acetate, dry (magnesium sulfate) filter concentrate purify (silica gel chromatography, eluting with 0:100 to 100% ethyl acetate:hexanes)

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

Procedure: Dissolve ethyl 4-acetyl-5-oxohexanoate (2.00 g, 9.99 mmol) in acetic acid (21 mL). Add methyl hydrazine (589 μL, 10.99 mmol) and stir at room temperature for 18 hr. Concentrate and dissolve residue in ethyl acetate. Wash ethyl acetate layer with saturated aqueous sodium bicarbonate solution. Extract aqueous layer twice with ethyl acetate, dry (magnesium sulfate), filter, concentrate and purify (silica gel chromatography, eluting with 0:100 to 100% ethyl acetate:hexanes) to give 3-(1,3,5-trimethyl-1H-pyrazol-4-yl)-propionic acid ethyl ester (1.95 g, 93%). MS (ES): m/z=211 [M+H]+. Concentrate dissolve residue in ethyl acetate Extract aqueous layer twice with ethyl acetate, dry (magnesium sulfate) filter concentrate purify (silica gel chromatography, eluting with 0:100 to 100% ethyl acetate:hexanes)

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

Procedure: 5.0 g of 4-acetyl-5-oxohexanoic acid ethyl ester and five drops 1,8-diazabicyclo-[5.4.0]-undec-7-ene were mixed and 2.6 g of neopentyl glycol diacrylate was added dropwise. The mixture was stirred for three hours to yield a highly viscous colorless oil. Gel permeation chromatography showed a main peak at 690 g/mol, nuclear magnetic resonance spectra and infrared spectrum are according to the expected structure. to yield a highly viscous colorless oil

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

Procedure: 25.7 g of 4-acetyl-5-oxohexanoic acid ethyl ester and 0.3 g of 1,8-diazabicyclo-[5.4.0]-undec-7-ene were mixed, and 35 g of fumaric acid diethyl ester was added at room temperature over 40 minutes. After stirring for 24 hours, the amount of 1,8-diazabicyclo-[5.4.0]-undec-7-ene was doubled and stirring continued until conversion was complete. 0.5 g of acetic acid and 50 ml of diethyl ether were added, and the solution was extracted with an aqueous potassium carbonate solution and water. Fractional distillation of the dry organic layer yielded 25.6 g of 4,4-diacetyl-5-(ethoxycarbonyl)-heptanedioic acid diethyl ester (boiling point: 170° C./0.002 mbar; purity: 93%; colorless). Content of the active structural element C3O2: 18%. stirring the solution was extracted with an aqueous potassium carbonate solution and water Fractional distillation of the dry organic layer

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

Procedure: To a mixture of 70 g of 2,4-pentandione and 1.72 g of trioctyl phosphine, 45 g of ethyl acrylate was added dropwise over 40 minutes, keeping the temperature at 0–5° C. by cooling. After stirring for 65 hours, 2 ml of acetic acid and 150 ml of diethyl ether were added, and the solution was extracted with an aqueous sodium carbonate solution and water. The organic layer was dried, and 4-acetyl-5-oxohexanoic acid ethyl ester was isolated by fractional distillation. was added dropwise over 40 minutes at 0–5° C. by cooling the solution was extracted with an aqueous sodium carbonate solution and water The organic layer was dried

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

Procedure: Dissolve ethyl 4-acetyl-5-oxohexanoate (2.00 g, 9.99 mmol) in acetic acid (21 mL). Add methyl hydrazine (589 μL, 10.99 mmol) and stir at room temperature for 18 hr. Concentrate and dissolve residue in ethyl acetate. Wash ethyl acetate layer with saturated aqueous sodium bicarbonate solution. Extract aqueous layer twice with ethyl acetate, dry (magnesium sulfate), filter, concentrate and purify (silica gel chromatography, eluting with 0:100 to 100% ethyl acetate:hexanes) to give 3-(1,3,5-trimethyl-1H-pyrazol-4-yl)-propionic acid ethyl ester (1.95 g, 93%). MS (ES): m/z=211 [M+H]+. Concentrate dissolve residue in ethyl acetate Extract aqueous layer twice with ethyl acetate, dry (magnesium sulfate) filter concentrate purify (silica gel chromatography, eluting with 0:100 to 100% ethyl acetate:hexanes)