Microwave assisted solid phase catalyst-free Biginelli synthesis of 3,4-dihydropyrimidin-2(1H)-one and 3,4-dihydropyrimidin-2(1H)-thione: A green approach, characterization and molecular crystal structures

ABSTRACT

Solid phase catalyst-free Biginelli synthesis of novel 5-carbethoxy-4-(3-bromo-4-hydroxy-5-methoxyphenyl)-6-methyl-3,4-dihydropyrimidin-2(1H)-one (C₁₅H₁₇BrN₂O₅) and 5-carbethoxy-4-(3-bromo-4-hydroxy-5-methoxyphenyl)-6-methyl-3,4-dihydropyrimidin-2(1H)-thione (C₁₅H₁₇BrN₂O₄S) has been carried out under microwave irradiation at 400W. The structures of both compounds were confirmed by ¹H NMR, ¹³C NMR, Mass, FT-IR, Elemental analysis, and single crystal X-ray diffraction method. The single crystals of both compounds were obtained by crystallization in 0.35 × 0.30 × 0.25 mm dimension for (C₁₅H₁₇BrN₂O₅) and 0.35 × 0.32 × 0.30 mm dimension for (C₁₅H₁₇BrN₂O₄S). Both compounds, (C₁₅H₁₇BrN₂O₅) and (C₁₅H₁₇BrN₂O₄S) crystallizes in the monoclinic P2₁/c space group and shows four and two intermolecular hydrogen bonds, respectively.

KEYWORDS:

• 3,4-Dihydropyrimidin-2(1H)-one
• 3,4-Dihydropyrimidin-2(1H)-thione; Microwave irradiation
• solid phase catalyst-free biginelli synthesis
• single crystal structure