diethyl 2-oxobutanedioate

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

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

Procedure: To a solution of N-methyl-1,2-phenylenediamine (6.1 g, 4.99 mmol) in MeOH (50 mL) was added in portion of oxalacetic acid diethyl ester (9.9 g, 5.26 mmol). The mixture was then stirred at rt for 1 h. The precipitate was collected via filtration and was washed with small amount of methanol to yield a pale brownish solid as the pure product: 1H NMR (DMSO-d6) δ=11.1 (bs, 1H), 7.45–7.42 (m, 1H), 7.32–7.29 (m, 1H), 7.15–7.10 (m, 2H), 5.53 (s, 1H), 4.14 (q, J=9.0 Hz, 2H), 3.51 (s, 3H), 1.23 (t, J=9.0 Hz, 3H); HPLC (CH3CN—H2O-0.1% TFA) (short column): Rt=3.91 min. The precipitate was collected via filtration was washed with small amount of methanol to yield a pale brownish solid as the pure product

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

Procedure: After heating a solution of 15.1 g of 3-nitrobenzaldehyde, 16 g of β-amino-γ-methoxycrotonic acid ethyl ester and 19 g of oxalacetic acid diethyl ester in 60 ml of ethanol under reflux for 12 hours, the mixture is evaporated in vacuo and 2-methoxymethyl-4-(3'-nitrophenyl)-1,4-dihydropyridine-3,5,6-tricarboxylic acid triethyl ester is obtained in almost quantitative yield, in the form of a yellow oil (nD50 =1.5353). under reflux for 12 hours the mixture is evaporated in vacuo

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

Procedure: 7.5 g of 3-nitrobenzaldehyde 9.5 g of oxalacetic acid diethyl ester and 7.2 g of β-ethyl-β-aminoacrylic acid ethyl ester in 40 ccs of ethanol are heated to the boil for several hours, and after cooling, filtration and washing (ether/petroleum ether) yellow crystals of melting point 153°C are obtained in 68% yield. after cooling filtration washing (ether/petroleum ether) yellow crystals of melting point 153°C are obtained in 68% yield

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

Procedure: 7.5 g of 3-nitrobenzaldehyde 9.5 g of oxalacetic acid diethyl ester and 7.2 g of β-ethyl-β-aminoacrylic acid ethyl ester in 40 ccs of ethanol are heated to the boil for several hours, and after cooling, filtration and washing (ether/petroleum ether) yellow crystals of melting point 153°C are obtained in 68% yield. after cooling filtration washing (ether/petroleum ether) yellow crystals of melting point 153°C are obtained in 68% yield

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

Procedure: A solution of 14.7 g of 2-azidobenzaldehyde, 19 g of oxalacetic acid diethyl ester and 13 g of β-aminocrotonic acid ethyl ester in 40 ccs of ethanol is heated to the boil overnight and evaporated in vacuo. Yellow-brown oil. evaporated in vacuo

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

Procedure: A solution of 14.7 g of 2-azidobenzaldehyde, 19 g of oxalacetic acid diethyl ester and 13 g of β-aminocrotonic acid ethyl ester in 40 ccs of ethanol is heated to the boil overnight and evaporated in vacuo. Yellow-brown oil. evaporated in vacuo

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

Procedure: 14.1 g of 3-chlorobenzaldehyde, 19 g of oxalacetic acid diethyl ester and 18.8 g of iminosuccinic acid diethyl ester in 60 ccs of ethanol are heated to the boil overnight and subsequently evaporated in vacuo. Yellow oil. subsequently evaporated in vacuo

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

Procedure: 14.1 g of 3-chlorobenzaldehyde, 19 g of oxalacetic acid diethyl ester and 18.8 g of iminosuccinic acid diethyl ester in 60 ccs of ethanol are heated to the boil overnight and subsequently evaporated in vacuo. Yellow oil. subsequently evaporated in vacuo

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

Procedure: 13.6 g of 3-methoxybenzaldehyde, 19 g of oxalacetic acid diethyl ester and 18.8 g of iminosuccinic acid diethyl ester in 50 ccs of ethanol are heated to the boil for several hours, and after evaporation a yellow oil is obtained. after evaporation a yellow oil is obtained

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

Procedure: 13.6 g of 3-methoxybenzaldehyde, 19 g of oxalacetic acid diethyl ester and 18.8 g of iminosuccinic acid diethyl ester in 50 ccs of ethanol are heated to the boil for several hours, and after evaporation a yellow oil is obtained. after evaporation a yellow oil is obtained

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

Procedure: 6.2 g of 3-fluorobenzaldehyde, 6.5 g of β-aminocrotonic acid ethyl ester and 9.5 g of oxalacetic acid diethyl ester in 40 ccs of ethanol are heated to the boil overnight, the mixture is evaporated in vacuo and a light yellow oil is obtained. the mixture is evaporated in vacuo a light yellow oil is obtained