Heteroaromatization of N-(p-toulyl)thioura to synthesize new pyrimidines

Thiourea 1, benzaldehyde, and ethyl cyanoacetate underwent cyclocondensation, selectively yielding pyrimidinethione 7. Reaction of thiourea 1 with malonamide and benzaldehyde yielded pyrimidine derivative 9. Reaction of thiourea 1 with ethyl acetoacetate afforded dipyrimidopyridine 12. Reaction of thiourea 1, ethyl acetoacetate, and aromatic aldehydes produced an isomeric pyrimidine mixture (14a/14b), while aza-Michael addition of thiourea 1 to benzalacetophenone 15 afforded pyrimidinthione 16. Cyclocondensation of thiourea 1 with benzalbarbituric acid 17 yielded the fused pyrimidopyrimidine system 19—reaction of thiourea 1 with cyclic α,β-unsaturated substrate 20, directly furnishing pyrimidine 22. Cycloaddition between 1 and benzylidene malononitrile gave pyrimidine derivative 24. Cyclocondensation of compound 1 with acetylacetone and benzaldehyde yielded pyrimidine derivative 25, which subsequently underwent condensation with benzaldehyde to afford cinnamoyl pyrimidine 27. Condensation of dimedone 28, benzaldehyde, and thiourea 1 generated pyrimidine 30. Cycloaddition of Compound 1 with maleic anhydride yielded thiazole derivative 35. KEY WORDS: Synthesis (chemical), Thiourea, Michael addition, Biginelli condition, Pyrimidine Bull. Chem. Soc. Ethiop. 2026, 40(5), 1021-1031 DOI: https://dx.doi.org/10.4314/bcse.v40i5.6