diethyl 3-oxohexanedioate

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

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

Procedure: A solution of 3-oxohexane-1,6-dioic acid diethyl ester (78.88 g), resorcinol (40.19 g) and ethanol (1 L) was saturated with hydrogen chloride gas during two hours at 0° C., tightly stoppered, let stand at room temperature over the weekend, shown by thin layer chromatography to contain unreacted 3-oxohexane-1,6-dioic acid diethyl ester, saturated again with hydrogen chloride gas during 45 minutes at 0° C., and let stand overnight at room temperature. Although thin layer chromatography still showed that the reaction was incomplete, the solution was partially (800 mL) stripped of volatiles and poured into ice-water. The resulting solid was collected by filtration and ethanol (300 mL) and aqueous sodium hydroxide solution (2.5N, 350 mL) were added. The mixture was stirred at room temperature and, when the reaction was complete, poured into hydrochloric acid (2N, 500 mL). A suspension of the resulting solid in methanol (300 mL) was stirred for 15 minutes at room temperature, cooled on ice and filtered. The resulting solid was washed with ether and dried affording 3-(7-hydroxy-4-coumarinyl)propionic acid (62.4 g, 73% yield). let stand at room temperature over the weekend The resulting solid was collected by filtration and ethanol (300 mL) and aqueous sodium hydroxide solution (2.5N, 350 mL) were added poured into hydrochloric acid (2N, 500 mL) A suspension of the resulting solid in methanol (300 mL) was stirred for 15 minutes at room temperature cooled on ice filtered The resulting solid was washed with ether dried

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

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

Procedure: A solution of 3-oxohexane-1,6-dioic acid diethyl ester (78.88 g), resorcinol (40.19 g) and ethanol (1 L) was saturated with hydrogen chloride gas during two hours at 0° C., tightly stoppered, let stand at room temperature over the weekend, shown by thin layer chromatography to contain unreacted 3-oxohexane-1,6-dioic acid diethyl ester, saturated again with hydrogen chloride gas during 45 minutes at 0° C., and let stand overnight at room temperature. Although thin layer chromatography still showed that the reaction was incomplete, the solution was partially (800 mL) stripped of volatiles and poured into ice-water. The resulting solid was collected by filtration and ethanol (300 mL) and aqueous sodium hydroxide solution (2.5N, 350 mL) were added. The mixture was stirred at room temperature and, when the reaction was complete, poured into hydrochloric acid (2N, 500 mL). A suspension of the resulting solid in methanol (300 mL) was stirred for 15 minutes at room temperature, cooled on ice and filtered. The resulting solid was washed with ether and dried affording 3-(7-hydroxy-4-coumarinyl)propionic acid (62.4 g, 73% yield). let stand at room temperature over the weekend The resulting solid was collected by filtration and ethanol (300 mL) and aqueous sodium hydroxide solution (2.5N, 350 mL) were added poured into hydrochloric acid (2N, 500 mL) A suspension of the resulting solid in methanol (300 mL) was stirred for 15 minutes at room temperature cooled on ice filtered The resulting solid was washed with ether dried

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

Procedure: A solution of 3-oxohexane-1,6-dioic acid diethyl ester (78.88 g), resorcinol (40.19 g) and ethanol (1 L) was saturated with hydrogen chloride gas during two hours at 0° C., tightly stoppered, let stand at room temperature over the weekend, shown by thin layer chromatography to contain unreacted 3-oxohexane-1,6-dioic acid diethyl ester, saturated again with hydrogen chloride gas during 45 minutes at 0° C., and let stand overnight at room temperature. Although thin layer chromatography still showed that the reaction was incomplete, the solution was partially (800 mL) stripped of volatiles and poured into ice-water. The resulting solid was collected by filtration and ethanol (300 mL) and aqueous sodium hydroxide solution (2.5N, 350 mL) were added. The mixture was stirred at room temperature and, when the reaction was complete, poured into hydrochloric acid (2N, 500 mL). A suspension of the resulting solid in methanol (300 mL) was stirred for 15 minutes at room temperature, cooled on ice and filtered. The resulting solid was washed with ether and dried affording 3-(7-hydroxy-4-coumarinyl)propionic acid (62.4 g, 73% yield). let stand at room temperature over the weekend The resulting solid was collected by filtration and ethanol (300 mL) and aqueous sodium hydroxide solution (2.5N, 350 mL) were added poured into hydrochloric acid (2N, 500 mL) A suspension of the resulting solid in methanol (300 mL) was stirred for 15 minutes at room temperature cooled on ice filtered The resulting solid was washed with ether dried

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

Procedure: By the procedures of Examples 2 and 3, diethyl 3-oxohexanedioate [Tetrahedron 23, p. 897 (1967)] and 3,5-dimethoxyaniline were converted to title product, recrystallized from ethyl acetate/cyclohexane, in 77% yield, m.p. 254°-256° C.; m/e 233 (m+); ir (KBr) 3448, 2857, 1680, 1639 cm-1.

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

Procedure: By the procedures of Examples 2 and 3, diethyl 3-oxohexanedioate [Tetrahedron 23, p. 897 (1967)] and 3,5-dimethoxyaniline were converted to title product, recrystallized from ethyl acetate/cyclohexane, in 77% yield, m.p. 254°-256° C.; m/e 233 (m+); ir (KBr) 3448, 2857, 1680, 1639 cm-1.

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

Procedure: By the procedures of Examples 2 and 3, diethyl 3-oxohexanedioate [Tetrahedron 23, p. 897 (1967)] and 3,5-dimethoxyaniline were converted to title product, recrystallized from ethyl acetate/cyclohexane, in 77% yield, m.p. 254°-256° C.; m/e 233 (m+); ir (KBr) 3448, 2857, 1680, 1639 cm-1.

Conditions: temp:20.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture consisting of 5.0 g (0.041 mole) of o-anisidine (available from the Aldrich Chemical Company, Inc. of Milwaukee, Wis.), 8.86 g (0.041 mole) of β-ketoadipic acid diethyl ester (available from Sigma Chemical Company of St. Louis, Mo.) and 6.07 g (0.041 mole) of triethyl orthoformate (also available from Aldrich) was placed in an open reaction flask and heated to 140° C. for a period of three hours, at which point no further amount of ethanol by-product formation could be observed to evolve from the reaction mixture. Upon completion of this step, the spent reaction mixture was allowed to cool to ambient temperatures (ca. 20° C.) on standing overnight for a period of approximately 16 hours. The resulting residual solid was thereafter triturated with petroleum ether and filtered to give 11.53 g (82%) of pure o-[2-ethoxycarbonyl-2-(3-ethoxycarbonylpropionyl)-1-ethylideneamino]anisole. The pure product was characterized by means of mass spectrum (MS) analysis and nuclear magnetic resonance (NMR) data. Upon completion of this step, the spent reaction mixture The resulting residual solid was thereafter triturated with petroleum ether filtered

Conditions: temp:20.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture consisting of 5.0 g (0.041 mole) of o-anisidine (available from the Aldrich Chemical Company, Inc. of Milwaukee, Wis.), 8.86 g (0.041 mole) of β-ketoadipic acid diethyl ester (available from Sigma Chemical Company of St. Louis, Mo.) and 6.07 g (0.041 mole) of triethyl orthoformate (also available from Aldrich) was placed in an open reaction flask and heated to 140° C. for a period of three hours, at which point no further amount of ethanol by-product formation could be observed to evolve from the reaction mixture. Upon completion of this step, the spent reaction mixture was allowed to cool to ambient temperatures (ca. 20° C.) on standing overnight for a period of approximately 16 hours. The resulting residual solid was thereafter triturated with petroleum ether and filtered to give 11.53 g (82%) of pure o-[2-ethoxycarbonyl-2-(3-ethoxycarbonylpropionyl)-1-ethylideneamino]anisole. The pure product was characterized by means of mass spectrum (MS) analysis and nuclear magnetic resonance (NMR) data. Upon completion of this step, the spent reaction mixture The resulting residual solid was thereafter triturated with petroleum ether filtered

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

Procedure: Diethyl-3-oxoadipate (10 g, 46 mmol) was added to methanol (225 ml) followed by ammonium formate (27.4 g, 460 mmol) and NaBH3CN (2.7 g, 46 mmol) at 25° C. After 24 h the methanol was removed in vacuo to leave a white mass. Methylene chloride was added and the mixture filtered. The methylene chloride was evaporated resulting in an oil which was dissolved in 1N HCl (200 ml) and extracted with ether (100 ml). The ether layer was discarded and the aqueous layer was made basic using solid K2CO3. The product was extracted into methylene chloride dried over Na2SO4 and evaporated to give Diethyl-3-aminopimaleate (7.5 g). 1H NMR (d6-DMSO) δ 1.25 (t, 3H, J=8Hz), 1.26 (t, 3H, J=8Hz), 1.8 (m,2H), 1.55 (bs, 2H), 3.18 (m, 1H), 4.13 (q, 4H, J=8Hz), 4.15 (q, 4H, J=8Hz); MS (FAB) m/e 218.3 (M+H+). After 24 h the methanol was removed in vacuo to leave a white mass the mixture filtered The methylene chloride was evaporated resulting in an oil which extracted with ether (100 ml) The product was extracted into methylene chloride dried over Na2SO4 evaporated to give Diethyl-3-aminopimaleate (7.5 g)

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

Procedure: Diethyl-3-oxoadipate (10 g, 46 mmol) was added to methanol (225 ml) followed by ammonium formate (27.4 g, 460 mmol) and NaBH3CN (2.7 g, 46 mmol) at 25° C. After 24 h the methanol was removed in vacuo to leave a white mass. Methylene chloride was added and the mixture filtered. The methylene chloride was evaporated resulting in an oil which was dissolved in 1N HCl (200 ml) and extracted with ether (100 ml). The ether layer was discarded and the aqueous layer was made basic using solid K2CO3. The product was extracted into methylene chloride dried over Na2SO4 and evaporated to give Diethyl-3-aminopimaleate (7.5 g). 1H NMR (d6-DMSO) δ 1.25 (t, 3H, J=8Hz), 1.26 (t, 3H, J=8Hz), 1.8 (m,2H), 1.55 (bs, 2H), 3.18 (m, 1H), 4.13 (q, 4H, J=8Hz), 4.15 (q, 4H, J=8Hz); MS (FAB) m/e 218.3 (M+H+). After 24 h the methanol was removed in vacuo to leave a white mass the mixture filtered The methylene chloride was evaporated resulting in an oil which extracted with ether (100 ml) The product was extracted into methylene chloride dried over Na2SO4 evaporated to give Diethyl-3-aminopimaleate (7.5 g)