Secobarbital, synthesis

Saxitoxin occurrence, 5, 604 Saxitoxiri, hydroxy-occurrence, 5, 604 Scholtz synthesis indolizines, 4, 466 Scillaren A occurrence, 3, 883 Scutellarein chemistry, 3, 697 Secobarbital, 3, 150 1,19-Secocorrin nomenclature, 1, 30 A/D-Secocorrin complexes cyclization, 4, 429 A/D-Secocorrin, Al8-dehydro-synthesis, 4, 429 A/D-Secocorrin, 1-oxo-synthesis, 4, 429 Secocorrins... 

The synthesis of sodium secobarbital is described in the patent2. Propyl-methyl-carbinol (I) is treated with anhydrous gaseous HBr, at a low temperature to reduce isomer formation, to produce 2-bromopentane (II). Malonic ester (III) is added to a solution of sodium in alcohol. This is followed by a slow addition of II. The solvent is removed by... 

The synthesis of barbiturates is relatively simple and relies on reactions that are now familiar enolate alkylations and nucleophilic acyl substitutions. Starting with diethyl malonate, or malonic ester, alkylation of the corresponding enolate ion with simple alkyl halides provides a wealth of different disubstituted malonic esters. Reaction with urea, (H2N)2C=0, then gives the product barbiturates by a twofold nucleophilic acyl substitution reaction of the ester groups with the -NH2 groups of urea (Figure 22.7). Amobarbi-tal (Amytal), pentobarbital (Nembutal), and secobarbital (Seconal) are typical examples. 

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