A Green and Efficient Method for the Preparation of 3,4-Dihydropyrimidin-2(1H)-ones Using Quaternary Ammonium-Treated Clay in Water

Table 2

Synthesis of 3,4-dihydropyrimidin-2(1H)-ones catalyzed by CTAB-modified clay.

Entry	R	R1	Time (h)	Yield (%)^a,b
4a	H	CH3	0.5	89
4b	4-NO2	CH3	0.75	91
4c	3-NO2	CH3	1.0	92
4d	4-OH	CH3	0.75	87
4e	2-MeO	CH3	1.0	88
4f	4-Cl	CH3	0.5	85
4g	2-Cl	CH3	1.0	88
4h	4-CH3	CH3	0.5	89
4i	H	EtO	0.75	89
4j	4-F	EtO	0.75	85
4k	4-CH3	EtO	0.5	90
4l	4-MeO	EtO	0.75	87
4m	4-Cl	EtO	0.5	90
4n	2-Cl	EtO	0.75	86
4o	4-NMe2	EtO	0.75	84

aProducts are known and were identified by comparison of their physical and spectral data with those of authentic samples [18–22].
^bIsolated yields.