3-(ethoxymethylidene)pentane-2,4-dione

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: A solution containing 0.38 g of 6-(4-aminophenyl)-4,5-dihydropyridazin-3(2H)one and 0.4 g of 3-ethoxymethylene-2,4-pentanedione in 5 ml of ethanol was refluxed for 1 h. Yield 0.3 g, mp 218°-222° C. was refluxed for 1 h

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

Procedure: 3-(ethoxymethylene)pentane-2,4-dione (Preparation 2, 8.6 g) was dissolved in Ether (30 mL) and cooled to 0° C. The reaction solution was then slowly treated with 1-methyl-2-(propan-2-ylidene)hydrazine (Preparation 1, 4.8 g) dropwise over 5 minutes, and then warmed and stirred at room temperature overnight. The reaction solution was purified directly by flash column chromatography (Biotage Quad 25; Eluent: 20% EtOH in EtOAc) to afford the title compound as a light red solid. (9.1 g, 84.0%). warmed The reaction solution was purified directly by flash column chromatography (Biotage Quad 25; Eluent: 20% EtOH in EtOAc)

Conditions: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of Acetylacetone (40 mL), Ethyl orthoformate (95.4 mL) and Acetic anhydride (54.2 mL) was heated to reflux (150° C.) for 1 hour. The reaction solution was cooled to room temperature and was directly subjected to flash column chromatography (E. Merck Silica Gel (˜120 g); Eluent: 100% EtOAc followed by 5% EtOH in EtOAc). Concentration of the fractions containing the pure product using a rotavap at 40° C. afforded the title compound as a dark red viscous oil (10.4 g, 17.0%). The reaction solution was cooled to room temperature Concentration of the fractions containing the pure product at 40° C.

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

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

Procedure: 3-(ethoxymethylene)pentane-2,4-dione (Preparation 2, 8.6 g) was dissolved in Ether (30 mL) and cooled to 0° C. The reaction solution was then slowly treated with 1-methyl-2-(propan-2-ylidene)hydrazine (Preparation 1, 4.8 g) dropwise over 5 minutes, and then warmed and stirred at room temperature overnight. The reaction solution was purified directly by flash column chromatography (Biotage Quad 25; Eluent: 20% EtOH in EtOAc) to afford the title compound as a light red solid. (9.1 g, 84.0%). warmed The reaction solution was purified directly by flash column chromatography (Biotage Quad 25; Eluent: 20% EtOH in EtOAc)

Conditions: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of Acetylacetone (40 mL), Ethyl orthoformate (95.4 mL) and Acetic anhydride (54.2 mL) was heated to reflux (150° C.) for 1 hour. The reaction solution was cooled to room temperature and was directly subjected to flash column chromatography (E. Merck Silica Gel (˜120 g); Eluent: 100% EtOAc followed by 5% EtOH in EtOAc). Concentration of the fractions containing the pure product using a rotavap at 40° C. afforded the title compound as a dark red viscous oil (10.4 g, 17.0%). The reaction solution was cooled to room temperature Concentration of the fractions containing the pure product at 40° C.

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

Procedure: To a solution of 3-(ethoxymethylene)pentane-2,4-dione (Perkin 1. 2000, 1455-1460, 1.95 g, 12.5 mmol) in MeOH (33 mL) was added a solution of ethyl hydrazinoacetate hydrochloride (2.09 g, 13.5 mmol) and conc.HCl (2.6 ml) in MeOH (10 ml) (pre-cooled to 0° C.) dropwise at −15° C. The resulting mixture was then stirred for 24 hours at room temperature. After removal of the solvent at room temperature, the residue was basified with 2N NaOH aq, and the aqueous layer was extracted several times with EtOAc. The combined organic extracts were dried over Na2SO4, and concentrated in vacuo. The aqueous layer was acidified to pH 1 with 2N HCl aq. and extracted with EtOAc 6 times. The combined organic extracts were dried over Na2SO4, and concentrated in vacuo to give the crude 2-(4-acetyl-5-methyl-1H-pyrazol-1-yl)acetic acid as a mixture of regioisomers (1.17 g, <51% yield). 1H NMR (300 MHz, DMSO-d6) δ 2.37 (3H, s), 2.43 (3H, s), 4.99 (2H, s), 7.81 (1H, s), 13.2 (1H, brs). dropwise at −15° C After removal of the solvent at room temperature the aqueous layer was extracted several times with EtOAc The combined organic extracts were dried over Na2SO4 concentrated in vacuo extracted with EtOAc 6 times The combined organic extracts were dried over Na2SO4 concentrated in vacuo

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

Procedure: To a solution of 3-(ethoxymethylene)pentane-2,4-dione (Perkin 1. 2000, 1455-1460, 1.95 g, 12.5 mmol) in MeOH (33 mL) was added a solution of ethyl hydrazinoacetate hydrochloride (2.09 g, 13.5 mmol) and conc.HCl (2.6 ml) in MeOH (10 ml) (pre-cooled to 0° C.) dropwise at −15° C. The resulting mixture was then stirred for 24 hours at room temperature. After removal of the solvent at room temperature, the residue was basified with 2N NaOH aq, and the aqueous layer was extracted several times with EtOAc. The combined organic extracts were dried over Na2SO4, and concentrated in vacuo. The aqueous layer was acidified to pH 1 with 2N HCl aq. and extracted with EtOAc 6 times. The combined organic extracts were dried over Na2SO4, and concentrated in vacuo to give the crude 2-(4-acetyl-5-methyl-1H-pyrazol-1-yl)acetic acid as a mixture of regioisomers (1.17 g, <51% yield). 1H NMR (300 MHz, DMSO-d6) δ 2.37 (3H, s), 2.43 (3H, s), 4.99 (2H, s), 7.81 (1H, s), 13.2 (1H, brs). dropwise at −15° C After removal of the solvent at room temperature the aqueous layer was extracted several times with EtOAc The combined organic extracts were dried over Na2SO4 concentrated in vacuo extracted with EtOAc 6 times The combined organic extracts were dried over Na2SO4 concentrated in vacuo

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

Procedure: To a solution of 3-(ethoxymethylene)pentane-2,4-dione (Perkin 1. 2000, 1455-1460, 1.95 g, 12.5 mmol) in MeOH (33 ml) was added a solution of 2,2,2-trifluoroethylhydrazine (1.54 g, 13.5 mmol) and conc.HCl (2.6 ml) in MeOH (10 ml) (pre-cooled at 0° C.) dropwise at −15° C. The resulting mixture was then stirred for 24 h at rt. After removal of the solvent at rt, the residue was basified with 2N NaOH aq, and the aqueous layer was extracted several times with EtOAc. The combined organic extracts were dried over Na2SO4, and concentrated in vacuo to give the crude product as a single regioisomer (1.41 g, 51% yield). 1H NMR (300 MHz, CDCl3) δ 2.46 (3H, s), 2.62 (3H, s), 4.66 (1H, d, J=6.0 Hz), 4.72 (1H, d, J=9.0 Hz), 7.92 (1H, s). MS (ESI) m/z 207 (M+H)+ dropwise at −15° C After removal of the solvent at rt the aqueous layer was extracted several times with EtOAc The combined organic extracts were dried over Na2SO4 concentrated in vacuo