Barbituric acid 5- -, sodium salt, preparation

Stxlium salts of the barbiturates are readily prepared and are water soluble. Their aqueous. solutions generate an alkaline pH. A classic incompatibility is the addition of an agent with an acidic pH in solution, which rc.sults in formation and precipitation of the free water-insoluble disubsliluied barbituric acid. Sodium salts of barbiturates in aqueous solution decompose at varying rates by base-catalyzed hydrolysis, generating ring-opened sails of carboxylic acids. 

Pentobarbital (5-ethyl-5-r-methylbutyl barbituric acid. Nembutal) [76-74-4] M 226.4, m 127 (dec), pKEst(i) 8.0, pKEst(2) 12.7. Soln of the sodium salt in 10% HCl was prepared and the acid was extracted by addition of ether. Then purified by repeated crystn from CHCI3. [Bucket and Sandorfy J Phys Chem 88 3274 1984.]... 

The combined ether extracts were washed with 5% aqueous sodium bicarbonate solution, dried over anhydrous sodium sulfate, and fractionally distilled in vacuo. The fraction boiling at about 145° to 150°C at the pressure of 0.5 mm of mercury, weighing 61 g and consisting of 1-methyl-5-allyl-5-(1-methyl-2-pentynyl) barbituric acid, was collected. The only distillate was substantially pure, and could be used as such In pharmaceutical preparation or a salt could be prepared therefrom according to the procedures disclosed hereinafter. On standing, the oil crystallized. The crystalline 1-methyl-5-allyl-5-( 1-methyl-2-pentynyl) barbituric acid melted at about 60° to 64°C after recrystallization from dilute ethanol. 

The sodium salt of 5-ethyl-5-(l-methyl-81-butenyl)barbituric acid is prepared by dissolving 23 parts of sodium in 350 parts of absolute alcohol in a vessel... 

The electrophoretic mobilities of C-labeled cholic, deoxycholic, and chenodeoxycholic acid and their corresponding taurine and glycine conjugates were determined by Norman (42). The paper electrophoresis was performed in barbiturate buffer of ionic strength 0.1, pH 8.6, in an electric field of 7.5 V/cm for 3 hr. When 1 pg of each acid, as the sodium salt dissolved in 25 pi of water, was applied to the paper strips, the isotope determination after electrophoresis showed broad peaks all with a mean mobility similar to that of albumin or slightly lower. The electrophoretic mobilities of all of the bile acids were influenced by the concentration in the solution applied and presented difficulties in identifying bile acids in natural extracts. The migration of bile salt-lecithin micelles on paper electrophoresis has been reported by Shimura (43). The micelles were prepared by addition of lecithin to mixed bile salts, which may have also contained cholesterol. 

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