5-ALLYL-5-[1-METHYLBUTYL]-2-THIOBARBITURIC ACID

Thiamylal, 5-allyl-5-(1- methylbutyl)-2-thiobarbituric acid, The sodium salt , Mr 276.36, is an amorphous powder soluble in water. It is prepared by condensation of thiourea with a malonic ester , .

Surital,Parke Davis,US,1951

Thiamylal is a barbiturate derivative with sedative, anticonvulsant and hypnotic effects. Thiamylal is used for induction in surgical anaesthesia as well as an anticonvulsant to counteract side effects from other anaesthetics. Thiamylal is a Controlled Substance.

ChEBI: A member of the class of barbiturates that is 2-thioxodihydropyrimidine-4,6(1H,5H)-dione substituted by a pentan-2-yl and prop-2-en-1-yl group at position 5.

In 450 cc of methanol is added 47 grams of sodium metal and the mixture allowed to completely react to form a methanol solution of sodium methoxide. The methanol solution of sodium methoxide is then cooled to 60°C and 68 grams of thiourea which has been thoroughly dried is added with stirring until a uniform solution is formed. Thereafter, 157 grams of diethyl allyl-(1- methylbutyl)malonate is added to the solution of the sodio derivative of thiourea at a temperature of 55°C and the condensation reaction mixture maintained at the said temperature for 24 hours. Methyl alcohol is removed under vacuum during the course of the reaction while maintaining a temperature of 55°C.
The viscous reaction mixture is then poured into 1.5 liters of ice water and agitated to form a uniform solution. The solution is treated with activated carbon and filtered. Thereafter, 80% acetic acid is added until the filtered solution remains acidic to litmus. The precipitate formed is filtered and washed thoroughly with distilled water. The product is air-dried at a temperature of 95° to 100°C for 48 hours to yield 133 grams of 5-allyl-5-(1- methylbutyl)-2-thiobarbituric acid having a melting point of 132° to 133°C and assaying at 99.5% pure, from US Patent 2,876,225.

Anesthetic