We performed a comparative theoretical study of the relaxation mechanisms of the excited states of uracil and 4-pyrimidinone with the CASSCF, CASPT2, and CC2 ab initio methods. The calculated vertical excitation energies agree with the experimental UV absorption maxima of the two compounds. Three low-lying conical intersections between the S(0) and S(1) states (one for uracil, two for 4-pyrimid...

A ferrocene-functionalised ureidopyrimidinone has been synthesised that can signal the solvent-induced tautomerism of the dimeric 4[1H]-pyrimidinone form to the monomeric 6[1H]-pyrimidinone form.

Herein, we studied the formation of thiones via C=O group conversion into C=S functional group-based tricyclic pyrimidinone systems using Lawesson’s reagent and phosphorus pentasulfide as thionation agents. Naturally occurring alkaloids deoxyvasicinone mackinazolinone were selected templates for modification furo[2,3-d]pyrimidinone pyrrolo[2,3-d]pyrimidinone scaffold. Research work was performe...

In the title compound, C(19)H(19)N(3)OS(2), the thio-pyran ring adopts a twist-chair conformation and the pyrimidinone unit is essentially planar, with a mean deviation of 0.0497 Å. The thio-phene ring is essentially planar with a maximum deviation of 0.024 (2) Å, while the pyrrolidine ring exhibits an envelope conformation. The pyrimidinone and thio-phene rings are almost coplanar, forming a d...

In the title compound, C(20)H(15)N(3)O(2)·CH(3)OH, the quinazolin-one ring system is approximately planar, the dihedral angle between the pyrimidinone ring and the adjacent benzene ring being 1.73 (6)°. The pyrimidinone ring makes dihedral angles of 77.58 (6) and 29.62 (6)°, respectively, with the hy-droxy-phenyl and phenyl rings. In the crystal, the components are connected by O-H⋯O and C-H⋯O ...

Since increasing evidence indicates that combination modality of cancer treatment is preferable, and a series of 5-halo-6-phenyl pyrimidinones has been found to induce interferon production and to stimulate a variety of immune responses, several were tested alone or in combination with cyclophosphamide (CY) against B16 melanoma and P388 leukemia. Thus far, 2-amino5-bromo-6-(3-fluorophenyl)-4(3H...

In the title mol-ecule, C(16)H(14)ClN(3)O(2), the dihedral angle between the chloro-phenyl and pyrimidinone rings is 14.8 (1)°, while the dihedral angle between the fused benzene ring and the pyrimidinone ring is 3.8 (1)°. In the crystal structure, intra-molecular N-H⋯O hydrogen bonds, together with inter-molecular O-H⋯O hydrogen-bonding inter-actions, are present.

pyrano [2,3-d] pyrimidinone derivatives have received considerable interest from the pharmaceutical industry due to their wide range of interesting biological and therapeutic properties. nano al2o3 was found to be a highly efficient solid acid catalyst for the preparation of pyrano [2,3-d] pyrimidinone derivatives from the reaction of barbituric acid, aryl aldehyde and malononitrile. al2o3 nano...

In the title mol-ecule, C(16)H(15)FN(4)O, the dihedral angle between the fluoro-substituted benzene ring and the pyrimidinone ring is 52.34 (7)°, while the dihedral angle between the fused benzene ring and the pyrimidinone ring is 3.30 (6)°. An intra-molecular N-H⋯N hydrogen bond may, in part, influence the conformation of the mol-ecule. In the crystal structure, inter-molecular N-H⋯N hydrogen ...

Aberrant cytosine methylation in promoter regions leads to gene silencing associated with cancer progression. A number of DNA methyltransferase inhibitors are known to reactivate silenced genes; including 5-azacytidine and 2-(1H)-pyrimidinone riboside (zebularine). Zebularine is a more stable, less cytotoxic inhibitor compared to 5-azacytidine. To determine the mechanistic basis for this differ...