Diethylbarbiturate

The structure of barbituric acid was the subject of disagreement for many years, but since 195 2 (52BSB44) the trioxo formulation (57 R = H) has been accepted generally, along with the fact that barbituric acid loses a proton, first from carbon (anion) and subsequently from nitrogen (dianion). Barbital (5,5-diethylbarbituric acid) adopts a similar trioxo form (57 R = Et) (69AX(B)1978). 

To be distinguished from Malonurea , a trade name ( ) once widely used for 5,5-diethylbarbituric acid (barbital). 

Diethylbarbituric acid (Barbital) [57-44-3] M Crystd from water or EtOH. Dried in a vacuum over P2O5. 

Sodium barbitone (sodium 5,5-diethylbarbiturate) [144-02-5] M 150.1, pKj 3.99, pKj ll.S (barbituric acid). Crystd from water (3mL/g) by adding an equal volume of EtOH and cooling to 5°. Dried under vacuum over P2O5. 

Under solid-liquid PTC conditions 5,5-diethylbarbituric acid was N,N-dialkylated in a good yield in the presence of a lipophilic ammonium salts and potassium carbonate when reaction mixtures were irradiated in a household microwave oven (Eq. 26). 

Problem 16.55 Barbiturates are sedative-hypnotic varieties of 5,5-dialkyl substituted barbituric acids. Write the reaction for the formation of Veronal (5,5-diethylbarbituric acid) from the condensation of urea with diethylmalonic ester. [See Problem 17.13(a)]. ... 

Diethylbarbituric acid, A002 Diethyl benzoyl phosphonate, AT83 Diethyl ci s-bromobutenedioate. 

NX - ANTIPYRINE, 4-(DIMETHYLAMINOI- molecular complex with 5,5-DIETHYlBARBITURIC ACIO (2 1)... 

In the presence of two equivalents of 5,5-diethylbarbiturate (DEB) or isocyanuric acid derivatives (CYA), dimelamines la-d form stable double rosette assemblies la-d3 (DEB) 6 in apolar solvents such as chloroform, benzene or toluene even at 10 4 M concentration (Figure 4.2).9,10 They consist of 9 different components held together by 36 hydrogen bonds. X-ray diffraction studies of lb3 (DEB)6 showed that the two rosette layers are tightly stacked on top of each other with an interatomic separation of 3.5 A at the edges and... 

The researchers Joseph von Mering and Emil Fischer, a student of von Baeyer, developed the first barbiturate drug to be marketed. Fischer produced 5.5-diethylbarbituric acid, a hypnotic (medication to help patients sleep) and sedative (medication to relax people with constant nervousness and anxiety). This sedative/hypnotic drug was known by the trade names Barbital, Veronal, and Dorminal. Barbital proved to be a more effective sedative/hypnotic agent and replaced the class of drugs, sedative bromides, which were used at the time.14... 

Patterns of hydrogen bonding found in three polymorphic forms of 5,5-diethylbarbituric acid. The graph-set descriptors are (a)... 

Finally, we mention a remarkable example of lateral resolution reported for supramolecular nanostructures on hopg [96]. Held together by 72 hydrogen bonds, the molecular nanostructure is formed from three melamine-substituted calix[4]arene units and twelve 5,5-diethylbarbiturate molecules (Fig. 31a). The nanostructure, basically a stack of four rosettes, has chiral symmetry. With its components all being achiral, both enantiomers are formed upon self-assembly in solution. Deposition of the tetrarosettes on hopg leaves this nanostructure intact and allows surface self-assembly. AFM studies revealed close-packed 2D lattices formed by the tetrarosettes on hopg... 

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