3- -2-ethylpropionic acid

C) Preparation of 0-(3-Amino-2,4,6-Triiodophenylj-a-Ethylpropionic Acid A solution of 5.0 g of m-amino-o -ethylhydrocinnamic acid in 100 cc of water containing 5 cc of concentrated hydrochloric acid is added over a period of A hour to a stirred solution of 3.2 cc of iodine monochloride in 25 cc of water and 25 cc of concentrated hydrochloric acid... 

The mixture is then cooled and sodium bisulfite added to decolorize. Recrystallization of the product from methanol gives about 8 g, MP 147° to 150°C. The /3-(3-amino-2,4,6-triiodophenyl)-0 -ethylpropionic acid may be purified further by precipitation of the morpholine salt from ether solution and regeneration of the free amino acid by treatment of a methanol solution of the morpholine salt with sulfur dioxide. The pure amino acid has the MP 155° to 156.5°C. 

A solution of 192 g 3-acetylamino-2,4,6-triiodophenol, sodium (0.35 mol) in 350 ml di-methylacetamide, was mixed with 107.5 g 3-(2-iodoethoxy)-2-ethylpropionic acid ethyl ester (0.35 mol) at 90°C with stirring over a period of about 20 to 30 minutes. Stirring was continued while the mixture was held at 95°C to 100°C for 16 hours. The solvent was then removed by distillation in a vacuum, and the residue was poured into 4,000 ml water. The solid precipitate formed was recovered and washed with water, dilute sodium carbonate solution, dilute sodium bisulfite solution, and again with much water. The ethyl ester was obtained in a yield of 220 g (90%). When recrystallized from 75% aqueous ethanol, it melted at 80°C to 86°C. 

Iodoethoxy)-2-ethylpropionic acid ethyl ester Manufacturing Process... 

Phenyl(3-a -"ethylpropionate ), 4-carboxamide] -tetrazanetll. Note a-ethylpropionate (or more correctly, in the opinion of the editor, a-ethylpropionatyl) is the proper name for the radical —CH(CH3).CCfe-C2H5, derived from a-propionic acid ethyl ester. (C6H5).N N.N[CH(CH3).C02.C2H5].NH(C0.NH2), mw 279.34, N 25.08%, crysts from aq ale, mp (melts with expln ca 125°)... 

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