Diethylbarbituric acid, complexes with

Aminopyrine forms complexes with barbiturates containing one or two molecules of aminopyrine for each molecule of barbiturate. These complexes have a synergistic action on the analgesic activity of the pyrazolinone.265 Two of these complexes have been marketed as analgesics under the names Allonal and Veramon. The former is a 1 1 complex with phenylisopropylbarbituric acid and the latter is a 2 1 complex with diethylbarbituric acid. A complex of aminopyrine with trichloroethylurethan has been sold as an analgesic under the trade name Compral. 

Barbiturates also form crystalline intermolecular complexes. Complexes of 5,5-diethylbarbituric acid with acetamide,411 urea,412 imidazole,413 2,4-diamino-5-(3,4,5-trimetoxybenzyl)pyrimidine,414 and N-methyl-2-pyr-idone415 have a 1 1 composition. 5-Ethyl-5-(3 -methylbutyl)barbituric acid with salicylamide forms the 1 1 complex as well.416 The former gives a crystalline 1 2 complex with 2-aminopyridine.417 1-Methyl-5,5-diethyl-barbituric acid also forms 1 1 complexes with dimethylacetamide and 9-ethyladenine.418 The structures of the inclusion complexes of barbiturates with cycloheptaamylose419 and with / -cyclodextrin79 were investigated in detail. Moreover, there are several examples of complexation of barbiturates with Cu(II),420,421 Co(II),422 Ag(I),423 lanthanides,424 and pentachloronit-... 

The complex between N,N -bis(4-chlorophenyl)melamine (R3 = R4 = P-C6H4CI) and diethylbarbituric acid (barbM Ri = R2 = CH2CH3) packs as shown in Figure 6. At the top, the straight-chain nature of the tapes (T = 1) can be seen, and the bottom end-on view shows tilted sheets. Each stack consists of head-to-tail dimers of tapes (S = 2), with one of these dimers drawn using thermal ellipsoids. 

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