7194. Pfeiffer's Substance

Nomenclature

CAS number: 8015-18-7
5,5-Diethyl-2,4,6(1H,3H,5H)-pyrimidinetrione mixture with 4-(dimethylamino)-1,2-dihydro-1,5-dimethyl-2-phenyl-3H-pyrazol-3-one; 4-(Dimethylamino)antipyrine compd with 5,5-diethylbarbituric acid (1:1); corps de Pfeiffer.
C21H29N5O4; mol wt 415.49.
C 60.71%, H 7.04%, N 16.86%, O 15.40%.

Description and references

A molecular compd of aminopyrine and barbital, prepd by repeated crystn of stoichiometric amounts of the components from a minimum of hot water: Pfeiffer, Z. Physiol. Chem. 146, 98 (1925).

Properties

Silky needles, mp 113-115°. At 115° the melt is turbid, but turns into a clear liquid at 140°. Freely sol in water. The aminopyrine moiety dissolves in benzene, while the barbital moiety precipitates out.