Diethyl sodium phthalimidomalonate

Diethyl sodium phthalimidomalonate (Barger and Weichselbaum, Organic Syntheses, 1943, Coll. Vol. II, 3B4) (6.52 g) was dissolved in boiling methyl ethyl ketone (BO ml) and a solution of p-nitrobenzyl chloride (3.44 g 1.0 mol) in the same solvent (20 ml) was added. Sodium iodide (ca 0.5 g) dissolved in hot methyl ethyl ketone (10 ml) was introduced, and produced an immediate precipitation. The mixture was refluxed for 1.5 hours, cooled, filtered, evaporated under vacuum and the residual gum crystallized from ethanol. The di-ethyl-p-nitrobenzyl-phthalimidomalonate formed colorless prisms (B8%), MP 103° to 105°C, sharpening to 104° to 105°C on recrystallizing from ethanol. 

N,N-Diethylselenourea, 36, 25 Diethyl sodium phthalimidomalonate, 30, 7 Diethyl succinate, 30, 19 Diethyl cm-A4-tetrahydrophthalate, 30, 29... 

Dichlorodibutyl ether, 27 Diels-Alder reaction of butadiene with maleic anhydride, 93 Diene synthesis of cis-A -tetrahydro-phthalic anhydride, 93 Diethyl benzalmalonate, 84 Diethyl carbonate, 44 Diethyl fumarate, 46 Diethyl cis-HEXAiiYDROPiiTHALATE, 29 Diethyl malonate, 70 Diethyl o-nitrobenzoylmalonatc, 71 Diethyl sodium phthalimidomalonate, 7... 

A. Triethyl a-phtkalimidoethane-a,a, -tricarboxylate. Three hundred and twenty-seven grams (1.0 mole) of diethyl sodium phthalimidomalonate and 735 g. (6.0 moles) of ethyl chloro-acetate (b.p. 144-145°) are placed in a 2-1. Claisen flask fitted with a reflux condenser and rubber stoppers. The mixture is heated under reflux in an oil bath at 150-160° for 2.25 hours. The excess ethyl chloroacetate is removed by distillation at 30 mm. until the heating bath temperature reaches 150° and no more distillate is obtained (Note 1). The brown residual mass is... 

Diethyl hydrogen phosphite, 31, 112 Diethyl malonate, 30, 70 Diethyl methylphosphonate, 31, 34 Diethyl o-nitrobenzoylmalonate, 30, 71 Diethyl sodium phthalimidomalonate, 30, 7... 

Diethyl 2-phthalimidomalonate [56680-61-5] M 305.3, m 72-74 , 73-74 , pK 9.17. Dissolve it in xylene and when the temperature is 30° add petroleum ether (b 40-60°) and cool to 20° whereby the malonate separates as a pale brown powder [Booth et al. J Chem Soc 666 1944], Alternatively, dissolve it in C6H6, dry it over CaCl2, filter, evaporate and the residual oil solidifies. Grind this with Et20, filter and wash it with Et20 until white in colour, and dry it in a vacuum. It forms a yellow sodium salt m 280°(dec). The anion has at 254nm (s 18.5K) [Clark Murray Org Synth Coll Vol I 271 1941, UV of Na salt Nnadi Wang J Am Chem Soc 92 4421 1970]. [Beilstein 21 H 487,211379, 21 III/IV 5264.]... 

Diethyl-p-nitrobenzyl-phthalimidomalonate (70 g) and sodium carbonate (70 g) in water (700 ml) were refluxed overnight with mechanical stirring (to avoid bumping). The clear brown solution was acidified with hydrochloric acid and refluxing and stirring were continued for a further 40 minutes. The mixture was cooled and the colorless precipitate (31 g) collected. A second crop (18.5 g) was obtained on evaporation of the mother liquors. Crystallization from aqueous ethanol gave the compound N-carboxybenzoyl-p-nitro-DL-phenylalanine as small needles, MP 198° to 200°C. 

Ethanol (80-100 ml), freshly, distilled from sodium, is placed in a 500-ml round-bottomed flask fitted with a reflux condenser and a calcium chloride tube, and sodium (4.6 g) is dissolved therein. This solution is treated at 60-70° with somewhat more than the calculated amount (62-63 g) of completely dry diethyl phthalimidomalonate, which dissolves to a yellow solution on shaking. If the temperature is kept within the stated limits the yellow crystalline sodio derivative soon begins to separate continuous shaking and suitable cooling are used to ensure complete separation in as fine a crystalline form as possible. Then the alcohol is distilled off in a vacuum, with extreme precautions to exclude moisture, the bath temperature being finally raised to 140°. The last traces of alcohol are removed by introduction of dry air free from carbon dioxide and repeated evacuation. 

Method Eight, Sorensen and Anderson (748). Diethyl bensylphthalim-idomalonate (A) is prepared in 80% yield from benzyl chloride mid sodium diethyl phthalimidomalonate. DL-Phenylalanine is prepared in 80% yield by hydrolysis of (A). The over-all yield is 64%. 

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