**10. Benzo[5,6]chromeno[2,3-d]pyrimidines**

Novel 2-thioxo-benzo[5,6]chromeno[2,3-d]pyrimidin-4-one derivatives were synthesized in aqueous media using cetylpyridinium chloride (CPC) as micellar catalyst in three-component one-pot reaction involving thiobarbituric acids, aromatic aldehydes and β-napthol [84]. The synthesized compounds were found to show antioxidant and cytotoxic activities (**Figure 12**).

**Figure 12.** *Synthesis of 2-thioxo-benzo[5,6]chromeno[2,3-d]pyrimidin-4-one derivatives.*

*Construction of Biologically Active Five- and Six-Membered Fused Ring Pyrimidine Derivatives… DOI: http://dx.doi.org/10.5772/intechopen.108842*
