Barbiturates are hypnotic agents. Veronal is derivative of barbituric acid. It can be synthesis by following sequence, then structure of veronal $(P)$ is :
$CH_2(CO_2 Et)_2 $ $\xrightarrow[Et-I]{EtO^{\circleddash}} \,\,\xrightarrow[Et-I]{EtO^{\circleddash}}
\,\,\overset{Urea}{\rightarrow} $ $(P)$