TETRABUTYLAMMONIUM HYDROGEN SULFATE: AN EFFICIENT CATALYST FOR THE SYNTHESIS OF 3,4-DIHYDROPYRIMIDIN-2(1H)-ONES UNDER SOLVENT-FREE CONDITIONS

Abstract

Tetrabutylammonium hydrogen sulfate (TBAHS) as[3pc] a solid protic acid and phase-transfer reagent catalyzed the three-component condensation reactions of aldehydes, 1,3-dicarbonyl compounds, and urea or thiourea under solvent-free conditions leading to 3,4-dihydropyrimidin-2(1H)-ones in high yields at 80°C.

Keywords:

• Biginelli reaction
• condensation reaction
• dihydropyrimidinones
• solvent free
• tetrabutylammonium hydrogen sulfate

Notes

^a Isolated yield.

^b Reddy et al. ⁵

^c Shaabani et al. ¹³

^d Eynde et al. ²⁶

^e Peng and Deng. ¹⁴

^f Singh et al. ²⁷

^a Benzaldehyde (1 mmol), ethyl acetoacetate (1 mmol), urea (1.5 mmol), reaction time 4 h at 80°C.