Dipotassium Salt of Nitroacetic Acid

B. Methyl Nitroacetate. A 2-1., three-necked, round-bottomed flask equipped with a sealed mechanical stirrer, a pressure-equalizing dropping funnel fitted with a calcium chloride drying tube, and a thermometer is charged with 70 g. (0.387 mole) of finely powdered dipotassium salt of nitroacetic acid (Note 4) and 465 ml. (11.6 moles) of methanol. 

Methyl nitroacetate has been prepared from nitromethane through the dipotassium salt of nitroacetic acid by the classical Steinkopf method3 but in lower yield. The dipotassium salt was obtained in 45% yield. The method has been improved by Matthews and Kubler4 but the salt must be recrystallized prior to esterification. 

Dipotassium Salt of Nitroacetic Acid A27-R Disol. See 2,4-Dinitroanisole A448-L Distyrylazobenzene. See Azostilbene A65S> R N1,N -(Ditetrazolyl-5)-hexazadiene A260-R Dithiocarbonic or Ditbioformic Acid, Azido Derivatives A632... 

Nitroacetic Acid. See Vol 1, A27-R under Acetic Acid and Derivatives. Its dipotassium salt, which is expl is briefly described, whereas its other expl salts, such as Pb, Ag and Hg are only mentioned. All of these salts are described by W. Steinkopf in Ber 42, 2026-31 (1909) CA 3,1438(1909)... 

The ethyl ester can also be prepared from ethyl acetoacetate (ethyl 3-oxobutanoate) by the method of Rodionov8 as well as via Steinkopf s method.3 Ethyl nitroacetate can be prepared in >70% yields from the dipotassium salt, ethanol, and sulfuric acid, with the addition of anhydrous magnesium sulfate in order to avoid the Nef reaction.9 The propyl and 2-propyl esters can also be obtained by this method. 

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