Ethyl isonitrosomalonate

Seventy grams (3.05 gram atoms) of sodium is dissolved in 1 1. of absolute ethanol (p. 142), and 500 g. (3.12 moles) of ethyl malonate is added to the resulting solution. The mixture is cooled in a cold water bath and stirred while 350 g. (3.40 moles) of dry n-butyl nitrite [ Org. Syntheses Coll. Yol. 2, 108 (1943)] is added slowly. The ethanol and butanol are removed by heating under reduced pressure, and the residue is treated with a mixture of 1 kg. of crushed ice and 600 ml. of 6 N sulfuric acid. The yellow oil that separates is removed by ether extraction, and the combined extracts are washed with saturated aqueous sodium bicarbonate solution, dried over sodium sulfate, and distilled. There is obtained 591 g. (87%) of ethyl isonitroso-malonate, b.p. 145-150°/3 mm. 

Distillation of ethyl isonitrosomalonate must be carried out with adequate protection against possible explosive decomposition of the material. 

---

C7HiiNOe, Ethyl isonitrosomalonate.. 156 C7H12NS, Cyclohexyl thiocyanate. 21... 

A mixture of 100 g. (0.52 mole) of ethyl isonitrosomalonate (p. 156), 150 ml. of absolute ethanol, and 15 g. of Raney nickel catalyst [iOrg. Syntheses, 21, 15 (1940)] is placed in a low-pressure hydrogenation apparatus [Org. Syntheses Coll. Vol. 1, 61 (1941)] and agitated at 40-50° and a hydrogen pressure of 18-50 lb. per sq. in. until absorption of hydrogen is complete (about 8 hours). The catalyst is removed by filtration, and the filtrate is distilled to give 60 g. (65%) of ethyl aminomalonate boiling at 83-87°/3-4 mm. The product should be used as soon as possible, since it is unstable. 

---