1-cyclobutylbutane-1,3-dione

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

Procedure: To a stirred suspension of 1-cyclobutylbutane-1,3-dione (69 mg, 0.49 mmol), N-[3-(trifluoromethyl)phenyl]urea (100 mg, 0.49 mmol) and 4-cyanobenzaldehyde (64.2 mg, 0.49 mmol) in tetrahydrofuran (250 ml) is added polyphosphoric acid ethyl ester (300 mg). The reaction mixture is stirred at reflux for 18 hours. After cooling to room temperature, the solvent is removed in vacuo and the crude product is purified by preparative HPLC (RP18 column; eluent: acetonitrile/0.1% aq. formic acid 10:90→90:10). at reflux for 18 hours the solvent is removed in vacuo the crude product is purified by preparative HPLC (RP18 column; eluent: acetonitrile/0.1% aq. formic acid 10:90→90:10)

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

Procedure: To a solution of NaNH2 (11.7 g, 91 mmol) in anhydrous ether (150 mL) under N2 at 30° C. was added dropwise a mixture of ethyl cyclobutanecarboxylate (19.2 g, 150 mmol) and acetone (21.75 g, 375 mmol). After addition, the reaction mixture was stirred for 4 h, then poured onto ice water with stirring. Ether was added and the unreached components were extracted into the organic phase. The clear aqueous extract was acidified to pH 5.0 with 2 N HCl, and then to pH 7.5 with Na2CO3. The solution was extracted with ether. The combined organic layers were dried (Na2SO4), filtered, and concentrated to give the crude product of 1-cyclobutyl-1,3-butanedione (9.7 g, 76%), which was used in the next step without further purification. 1H NMR (400 MHz, CDCl3-d3) δ 5.42 (s, 1H), 3.66 (s, 1H), 2.11-2.23 (m, 4H), 2.02 (s, 3H), 1.93-1.99 (m, 2H). After addition poured onto ice water with stirring the unreached components were extracted into the organic phase The clear aqueous extract The solution was extracted with ether The combined organic layers were dried (Na2SO4) filtered concentrated

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

Procedure: To a solution of NaNH2 (11.7 g, 91 mmol) in anhydrous ether (150 mL) under N2 at 30° C. was added dropwise a mixture of ethyl cyclobutanecarboxylate (19.2 g, 150 mmol) and acetone (21.75 g, 375 mmol). After addition, the reaction mixture was stirred for 4 h, then poured onto ice water with stirring. Ether was added and the unreached components were extracted into the organic phase. The clear aqueous extract was acidified to pH 5.0 with 2 N HCl, and then to pH 7.5 with Na2CO3. The solution was extracted with ether. The combined organic layers were dried (Na2SO4), filtered, and concentrated to give the crude product of 1-cyclobutyl-1,3-butanedione (9.7 g, 76%), which was used in the next step without further purification. 1H NMR (400 MHz, CDCl3-d3) δ 5.42 (s, 1H), 3.66 (s, 1H), 2.11-2.23 (m, 4H), 2.02 (s, 3H), 1.93-1.99 (m, 2H). After addition poured onto ice water with stirring the unreached components were extracted into the organic phase The clear aqueous extract The solution was extracted with ether The combined organic layers were dried (Na2SO4) filtered concentrated

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

Procedure: To a solution of NaNH2 (11.7 g, 91 mmol) in anhydrous ether (150 mL) under N2 at 30° C. was added dropwise a mixture of ethyl cyclobutanecarboxylate (19.2 g, 150 mmol) and acetone (21.75 g, 375 mmol). After addition, the reaction mixture was stirred for 4 h, then poured onto ice water with stirring. Ether was added and the unreacted components were extracted into the organic phase. The clear aqueous extract was acidified to pH 5.0 with 2N HCl, and then to pH 7.5 with Na2CO3. The solution was extracted with ether. The combined organic layers were dried (Na2SO4), filtered, and concentrated to give the crude product of 1-cyclobutyl-1,3-butanedione (9.7 g, 76%), which was used in the next step without further purification. 1H NMR (400 MHz, CDCl3-d3) δ 5.42 (s, 1H), 3.66 (s, 1H), 2.11-2.23 (m, 4H), 2.02 (s, 3H), 1.93-1.99 (m, 2H). After addition poured onto ice water with stirring the unreacted components were extracted into the organic phase The clear aqueous extract The solution was extracted with ether The combined organic layers were dried (Na2SO4) filtered concentrated

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

Procedure: To a solution of NaNH2 (11.7 g, 91 mmol) in anhydrous ether (150 mL) under N2 at 30° C. was added dropwise a mixture of ethyl cyclobutanecarboxylate (19.2 g, 150 mmol) and acetone (21.75 g, 375 mmol). After addition, the reaction mixture was stirred for 4 h, then poured onto ice water with stirring. Ether was added and the unreacted components were extracted into the organic phase. The clear aqueous extract was acidified to pH 5.0 with 2 N HCl, and then to pH 7.5 with Na2CO3. The solution was extracted with ether. The combined organic layers were dried (Na2SO4), filtered, and concentrated to give the crude product of 1-cyclobutyl-1,3-butanedione (9.7 g, 76%), which was used in the next step without further purification. 1H NMR (400 MHz, CDCl3-d3) δ 5.42 (s, 1H), 3.66 (s, 1H), 2.11-2.23 (m, 4H), 2.02 (s, 3H), 1.93-1.99 (m, 2H). After addition poured onto ice water with stirring the unreacted components were extracted into the organic phase The clear aqueous extract The solution was extracted with ether The combined organic layers were dried (Na2SO4) filtered concentrated

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

Procedure: To a solution of NaNH2 (11.7 g, 91 mmol) in anhydrous ether (150 mL) under N2 at 30° C. was added dropwise a mixture of ethyl cyclobutanecarboxylate (19.2 g, 150 mmol) and acetone (21.75 g, 375 mmol). After addition, the reaction mixture was stirred for 4 h, then poured onto ice water with stirring. Ether was added and the unreacted components were extracted into the organic phase. The clear aqueous extract was acidified to pH 5.0 with 2 N HCl, and then to pH 7.5 with Na2CO3. The solution was extracted with ether. The combined organic layers were dried (Na2SO4), filtered, and concentrated to give the crude product of 1-cyclobutyl-1,3-butanedione (9.7 g, 76%), which was used in the next step without further purification. 1H NMR (400 MHz, CDCl3-d3) δ 5.42 (s, 1H), 3.66 (s, 1H), 2.11-2.23 (m, 4H), 2.02 (s, 3H), 1.93-1.99 (m, 2H). After addition poured onto ice water with stirring the unreacted components were extracted into the organic phase The clear aqueous extract The solution was extracted with ether The combined organic layers were dried (Na2SO4) filtered concentrated

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

Procedure: To a stirred suspension of 1-cyclobutylbutane-1,3-dione (69 mg, 0.49 mmol), N-[3-(trifluoromethyl)phenyl]urea (100 mg, 0.49 mmol) and 4-cyanobenzaldehyde (64.2 mg, 0.49 mmol) in tetrahydrofuran (250 ml) is added polyphosphoric acid ethyl ester (300 mg). The reaction mixture is stirred at reflux for 18 hours. After cooling to room temperature, the solvent is removed in vacuo and the crude product is purified by preparative HPLC (RP18 column; eluent: acetonitrile/0.1% aq. formic acid 10:90→90:10). at reflux for 18 hours the solvent is removed in vacuo the crude product is purified by preparative HPLC (RP18 column; eluent: acetonitrile/0.1% aq. formic acid 10:90→90:10)

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

Procedure: To a stirred suspension of 1-cyclobutylbutane-1,3-dione (69 mg, 0.49 mmol), N-[3-(trifluoromethyl)phenyl]urea (100 mg, 0.49 mmol) and 4-cyanobenzaldehyde (64.2 mg, 0.49 mmol) in tetrahydrofuran (250 ml) is added polyphosphoric acid ethyl ester (300 mg). The reaction mixture is stirred at reflux for 18 hours. After cooling to room temperature, the solvent is removed in vacuo and the crude product is purified by preparative HPLC (RP18 column; eluent: acetonitrile/0.1% aq. formic acid 10:90→90:10). at reflux for 18 hours the solvent is removed in vacuo the crude product is purified by preparative HPLC (RP18 column; eluent: acetonitrile/0.1% aq. formic acid 10:90→90:10)

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

Procedure: To a solution of NaNH2 (11.7 g, 91 mmol) in anhydrous ether (150 mL) under N2 at 30° C. was added dropwise a mixture of ethyl cyclobutanecarboxylate (19.2 g, 150 mmol) and acetone (21.75 g, 375 mmol). After addition, the reaction mixture was stirred for 4 h, then poured onto ice water with stirring. Ether was added and the unreacted components were extracted into the organic phase. The clear aqueous extract was acidified to pH 5.0 with 2 N HCl, and then to pH 7.5 with Na2CO3. The solution was extracted with ether. The combined organic layers were dried (Na2SO4), filtered, and concentrated to give the crude product of 1-cyclobutyl-1,3-butanedione (9.7 g, 76%), which was used in the next step without further purification. 1H NMR (400 MHz, CDCl3-d3) δ 5.42 (s, 1H), 3.66 (s, 1H), 2.11-2.23 (m, 4H), 2.02 (s, 3H), 1.93-1.99 (m, 2H). After addition poured onto ice water with stirring the unreacted components were extracted into the organic phase The clear aqueous extract The solution was extracted with ether The combined organic layers were dried (Na2SO4) filtered concentrated

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

Procedure: To a solution of NaNH2 (11.7 g, 91 mmol) in anhydrous ether (150 mL) under N2 at 30° C. was added dropwise a mixture of ethyl cyclobutanecarboxylate (19.2 g, 150 mmol) and acetone (21.75 g, 375 mmol). After addition, the reaction mixture was stirred for 4 h, then poured onto ice water with stirring. Ether was added and the unreacted components were extracted into the organic phase. The clear aqueous extract was acidified to pH 5.0 with 2 N HCl, and then to pH 7.5 with Na2CO3. The solution was extracted with ether. The combined organic layers were dried (Na2SO4), filtered, and concentrated to give the crude product of 1-cyclobutyl-1,3-butanedione (9.7 g, 76%), which was used in the next step without further purification. 1H NMR (400 MHz, CDCl3-d3) δ 5.42 (s, 1H), 3.66 (s, 1H), 2.11-2.23 (m, 4H), 2.02 (s, 3H), 1.93-1.99 (m, 2H). After addition poured onto ice water with stirring the unreacted components were extracted into the organic phase The clear aqueous extract The solution was extracted with ether The combined organic layers were dried (Na2SO4) filtered concentrated

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

Procedure: To a solution of NaNH2 (11.7 g, 91 mmol) in anhydrous ether (150 mL) under N2 at 30° C. was added dropwise a mixture of ethyl cyclobutanecarboxylate (19.2 g, 150 mmol) and acetone (21.75 g, 375 mmol). After addition, the reaction mixture was stirred for 4 h, then poured onto ice water with stirring. Ether was added and the unreacted components were extracted into the organic phase. The clear aqueous extract was acidified to pH 5.0 with 2 N HCl, and then to pH 7.5 with Na2CO3. The solution was extracted with ether. The combined organic layers were dried (Na2SO4), filtered, and concentrated to give the crude product of 1-cyclobutyl-1,3-butanedione (9.7 g, 76%), which was used in the next step without further purification. 1H NMR (400 MHz, CDCl3-d3) δ 5.42 (s, 1H), 3.66 (s, 1H), 2.11-2.23 (m, 4H), 2.02 (s, 3H), 1.93-1.99 (m, 2H). After addition poured onto ice water with stirring the unreacted components were extracted into the organic phase The clear aqueous extract The solution was extracted with ether The combined organic layers were dried (Na2SO4) filtered concentrated

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

Procedure: To a solution of NaNH2 (11.7 g, 91 mmol) in anhydrous ether (150 mL) under N2 at 30° C. was added dropwise a mixture of ethyl cyclobutanecarboxylate (19.2 g, 150 mmol) and acetone (21.75 g, 375 mmol). After addition, the reaction mixture was stirred for 4 h, then poured onto ice water with stirring. Ether was added and the unreacted components were extracted into the organic phase. The clear aqueous extract was acidified to pH 5.0 with 2 N HCl, and then to pH 7.5 with Na2CO3. The solution was extracted with ether. The combined organic layers were dried (Na2SO4), filtered, and concentrated to give the crude product of 1-cyclobutyl-1,3-butanedione (9.7 g, 76%), which was used in the next step without further purification. 1H NMR (400 MHz, CDCl3-d3) δ 5.42 (s, 1H), 3.66 (s, 1H), 2.11-2.23 (m, 4H), 2.02 (s, 3H), 1.93-1.99 (m, 2H). After addition poured onto ice water with stirring the unreacted components were extracted into the organic phase The clear aqueous extract The solution was extracted with ether The combined organic layers were dried (Na2SO4) filtered concentrated