ChemicalBook CAS DataBase List 2-Thiobarbituric acid

2-Thiobarbituric acid synthesis

5synthesis methods

Product Name:2-Thiobarbituric acid
CAS Number:504-17-6
Molecular formula:C4H4N2O2S
Molecular Weight:144.15

2-thiobarbituric acid was synthesized by the reaction of diethyl malonate with thiourea. Dissolve thiourea in methanol, add sodium methoxide and diethyl malonate, heat under reflux for 4-5h, then distill under reduced pressure to recover methanol to the end, and add hydrochloric acid to acidify to pH 1-2 after cooling. After standing overnight, thiobarbituric acid crystals were precipitated, filtered, and recrystallized with water to obtain the pure product.

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Yield:504-17-6 80%

Reaction Conditions:

with sodium in ethanol; for 6 h;Reflux;

Steps:

Synthesis of Thiobarbituric acid

About 6g (0.25mol) of sodium metal isdissolved in 200 mL of ethanol. To this solution 15g(0.25mol) of thiourea and 40 mL of diethyl malonateis added. The reaction mixture is reuxed for 6 hrsin an oil bath and then vacuum distillated to makeethanol recovery. The clear solution thus obtained isfltered, cooled in ice bath overnight and the resultingsolution is acidifed with HCl. The crude productobtained is collected, washed with 50 mL water anddried in oven at 105°C-110C for nearly 4 hrs. Theobtained compound Thiobarbituric acid (TBA) ispurifed by recrystallization with ethanol and theirrespective melting point is about 243C with 80%yield is obtained.

References:

Kalaiarasi;Manivarman [Oriental Journal of Chemistry,2017,vol. 33,# 1,p. 304 - 317]