5-Ethyl-5- Thiobarbituric Acid Sodium Salt

Thiopental Sodium, 5.Ethyldihydro-5 ( I-methyl-butyl)-2-thioxo-4,6(lH,SH)-pyrimidinedione monosodium salt 5-ethyl-5-iI-methy(butyl)-2-thiobarbituric acid sodium salt thiomebumal sodium penthiobarbital sodium thiopen -tone sodium thionembutal Pentothal Sodium Nesdonal Sodium Intraval Sodium Trapanal Thiothal Sodium. C,.-Hl7N2Na02S mol wt 264.33. C 49.98%, H 6,48%, N 10.60%, Na 8,70%, O 12-11%, S 12.13%. Prepn U.S. pats. 2,153,729 (1939) 2,876,225 (1959). Prepn of nonhygrosopic crystals Hartop, U.S. pat. 3,109,001 (1963 to Abbott). Acute toxicity Christensen, Lee, Toxicol. Appl. Pharmacol. 26, 495 (1973). 

Dissolve 13 g. of sodium in 30 ml. of absolute ethanol in a 250 ml. flask carrying a reflux condenser, then add 10 g. (9 5 ml.) of redistilled ethyl malonate, and place the flask on a boiling water-bath. Without delay, add a solution of 5 3 g. of thiourea in a minimum of boiling absolute ethanol (about 100 ml.). The sodium salt of thiobarbituric acid rapidly begins to separate. Fit the water-condenser with a calcium chloride guard-tube (Fig. 61, p. 105), and boil the mixture on the water-bath for 1 hour. Cool the mixture, filter off the sodium salt at the pump and wash it with a small quantity of cold acetone. Dissolve the salt in warm water and liberate the acid by the addition of 30 ml. of concentrated hydrochloric acid diluted with 30 ml. of water. Cool the mixture, filter off the thiobarbituric acid, and recrystallise it from hot water. Colourless crystals, m.p. 245 with decomposition (immersed at 230°). Yield, 3 5 -4 0 g. 

Nakamiya strain of Japanese encephalitis virus in mice [201]. Thiobarbiturates of type (XLIV, R = C11H23 to C18H37) are claimed to have antiviral activity, especially against influenza [202]. In a related patent the allyl substitution is extended to include Ci-Cg derivatives, which may be alkyl, alkenyl, chloroalkenyl, cyclohexyl or cyclohexenyl [203]. 5-Butyl-5-ethyl-barbituric acid and the 1-methylbutyl analogue (pentobarbitone), as well as two thiouracil derivatives, were found to have a direct virucidal action in vitro on poliomyelitis viruses in monkey testicular and kidney cultures [204]. Among a series of 5-halo, 5-acyl, 5-benzylidene, and 5-phenylcarbamoyl derivatives of 1-H, 1-methyl, and 1-phenylbarbituric acids, the sodium salt... 

The sodium salt of 5-ethyl-5(l-methylbutyl)-thiobarbituric acid Pentothal, Thiopental) was determinedwith silver nitrate as titrant and either a dropping mercury or rotating platinum electrode. 

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