The Synthesis of 2,4-Diketo-5-phenyl-δ5-7-oxa-1,3-diazabicyclo[4.4.0]decane and 2,4-Diketo-3-phenyl-δ5-7-oxa-1,5-diazabicyclo[4.4.0]decane

In an attempt to secure 5-phenyl bioyclo barbiturates, N-(haloalkyl)-5-phenylbarbituric acids were prepared and converted to their corresponding thallous salts. Nitrourea and alkanolamines were allowed to react to produce N-(hydroxyalkyl)ureas, which were converted to the corresponding N-(hydroxyalkyl)-5-phenylbarbituric acids and via these alcohols to the halides. When cyclization of the thallous salts of the N-(halopropyl)-5-phenylbarbituric acids was attempted in benzene-water, no intramolecular C-alkylation occurred and the only product isolated was 2,4-diketo-3-phenyl-δ5-7-oxa-1,5-diazabicyclo[4.4.0]decane. Utilizing anhydrous benzene as the solvent for the cyclization reaction, the product obtained was 2,4-diketo-5-phenyl-δ5-7-oxa-1,3-diazabicyclo-[4.4.0] decane.