Preparation of barbital
Preparation of barbital from diethyl diethylmalonate and urea
16 g of sodium are dissolved in 300 g of absolute alcohol, the obtained solution is cooled to room temperature, and 50 g of diethyl diethylmalonate are added. 20 g of pulverized and carefully dried urea are then dissolved in the mixture by gentle warming and the whole is heated in an autoclave at 108° C for 5 hours. The precipitated sodium salt of diethylbarbituric acid, is filtered, washed with alcohol, dissolved in water, and converted into the free acid by adding concentrated hydrochloric acid. After recrystallization from water, the yield of barbital (m.p. 183-185° C) is 27.5 g. Barbital so obtained is not quite pure, and the purity could be increased by гесrystallization from 95 per cent alcohol.
Preparation of barbital from diethyl cyanoacetic ester and urea
46 g of sodium are dissolved in 800 g of absolute alcohol, and, after cooling, 70 g of powdered urea and 169 g of diethyl cyanoacetic ester are added, and the mixture is refluxed for 3 hours. The alcohol is then distilled off, the residue dissolved in water, extracted with ether, neutralized with concentrated hydrochloric acid, and the precipitated iminodiethyl malonyl urea is purified by recrystallization from water yielding product with melting point 195° C. 100 g of iminodiethyl malonyl urea are dissolved in 500 ml of 3 N-hydrochloric acid and the solution is boiled for a short time. Diethyl barbituric acid (barbital) crystallizes out on cooling and is filtered off and recrystallized from water.
Preparation of barbital from diethylmalonyl chloride and urea
1 mol of diethyl malonic acid is warmed gently with 2 moles of phosphorus pentachloride the diethylmalonyl chloride is separated from phosphorus oxychloride, and purified by distillation collecting fraction passing at 197° C. 1 mole of diethylmalonyl chloride is mixed with 1.1 mole of finely powdered dry urea and heated for 20 hours at 90-100° C. Hydrochloric acid is evolved, and finally there remains a solid mass which, on crystallization from hot water, affords pure barbital.
An advanced laboratory manual of organic chemistry, M. Heidelberger, 43-45, 64-65, 1923
barbital, Barbitone, Veronal, Diemal, 5,5-Diethylbarbituric acid, Ethylbarbital, Vesperal, Malonal, Uronal, Diethylmalonylurea, DEBA, Veroletten, Verolettin, Dormonal, Hypnogene, Sedeval, Diethylbarbitone, 57-44-3, Barbitonum, Diemalum, Diethylbarbituric acid, 2,4,6(1H,3H,5H)-Pyrimidinetrione, 5,5-diethyl-, Barbituric acid, 5,5-diethyl-, Barbital (VAN), Barbitale [DCIT], Medinal, Barbitalum, Barbitale, CHEBI:31252, Barbitalum [INN-Latin], UNII-5WZ53ENE2P, diethylmalonyl urea, NSC 31352, Barbital (TN), CCRIS 7420, 5,5-diethylpyrimidine-2,4,6(1H,3H,5H)-trione, DEA No. 2145, Kyselina 5,5-diethylbarbiturova, 5,5-Diethyl-2,4,6(1H,3H,5H)-pyrimidinetrione, Barbital [INN:JAN], AC1L1DCX, EINECS 200-331-2, CHEMBL444, BRN 0163999, Oprea1_012884, Oprea1_497227, Kyselina 5,5-diethylbarbiturova [Czech], NCGC00159419-02, B0375_SIGMA, AI3-02727, 5,5-diethyl-1,3-diazinane-2,4,6-trione, 31995_FLUKA, 31995_SIGMA, C8H12N2O3, FTOAOBMCPZCFFF-UHFFFAOYSA-N, WLN: T6VMVMV FHJ F2 F2, NSC31352, ZINC13545632, DB01483, NCGC00159419-03, NCGC00159419-04, LS-24148, 7979P, DSSTox_CID_2643, D01740, DSSTox_RID_76671, DSSTox_GSID_22643, 5-24-09-00137 (Beilstein Handbook Reference), 2,4,6(1H,3H,5H)-Pyrimidinetrione, 5,5-diethyl- (9CI), Dormileno, CAS-57-44-3, InChI=1/C8H12N2O3/c1-3-8(4-2)5(11)9-7(13)10-6(8)12/h3-4H2,1-2H3,(H2,9,10,11,12,13, Barbital Faes Brand, Faes Brand of Barbital, CID2294, Barbital (JP15/INN), Barbital (JP16/INN), Epitope ID:117124, Barbituric acid,5-diethyl-, 5WZ53ENE2P, D001462, SCHEMBL43818, CTK8E5105, MolPort-001-783-065, MolPort-003-890-764, Pharmakon1600-01900040, Tox21_111650, DAP001350, NSC-31352, NSC759567, AKOS015903028, Tox21_111650_1, CCG-214014, MCULE-2107172999, NSC-759567, 5,5-Diethyl-pyrimidine-2,4,6-trione, AN-23584, TR-020051, FT-0662476, FT-0662477, 5,5-diethylhexahydropyrimidine-2,4,6-trione, 2,6(1H,3H,5H)-Pyrimidinetrione, 5,5-diethyl-, I14-19206, 3B3-052163