In the first paper'of this series a number of derivatives of cyclobutane-1, 5-spiro-pyrimidine were described. They may be regarded as variously substituted barbituric acids in which the 5-carbon atom enters into a 4-membered hydrocarbon ring. The method of preparation consists in condensing an a, a-dibromo-paraffin with ethyl malonate with formation of a cycloparaffin-1, l-dicarboxylic ester; the second ring is closed by condensation of the two ...
![2,4-diaza-spiro[5.5]undecane-1,3,5-trione Structure](https://image.chemsrc.com/caspic/387/52-44-8.png)
