Structural Investigation of Two 4-AryIhexahydro-1H,3H-pyrido[1,2-c]pyrimidine-1,3-diones

Abstract

4-A rylhexahydro-l//,3//-pyrido[l,2-c]pyrim idine-l,3-dione Derivatives, Hydrogen Bonds, Dimers The X-ray crystal structure determination o f 4-(4'-fluorophenyl)hexahydro-l//,3//-pyrido[l,2-c]pyrim idine-l,3-dione (5) and 4-(4'-chlorophenyl)hexahydro-l//,3//-pyrido [1,2-c]pyrimidine-l,3-dione (8) is reported. The crystal structures show the formation o f centrosym metric dimers via intermolecular N-H -O hydrogen bonds. The saturated ring adopts a slightly distorted sofa conformation both in 5 and in 8. In either compound the planar phenyl ring is twisted with respect to the pyrimidine-1,3-dione fragment.