Magnetic core–shell Carrageenan moss/Fe3O4: a polysaccharide-based metallic nanoparticles for synthesis of pyrimidinone derivatives via Biginelli reaction

Table 2 Synthesis of pyrimidine derivatives under optimum reaction conditions*

Entry	R¹	X	R²	Product	Time (min)	Yield (%)	Mp (°C)
Entry	R¹	X	R²	Product	Time (min)	Yield (%)	Observed	Reported [Refs]
1	4-Cl	O	Et		60	95	210–212	213–214 [14]
2	4-Me	O	Et		90	73	213–215	214–217 [15]
3	4-OMe	O	Et		90	87	200–202	202–203 [16]
4	2-NO₂	O	Et		60	85	220–221	220 [17]
5	3-NO₂	O	Et		45	76	214–216	217 [18]
6	H	O	Me		60	87	210–212	207–210 [19]
7	4-Cl	O	Me		60	85	205–207	204–206 [20]
8	4-OMe	O	Me		45	93	190–192	191–193 [19]
9	4-Cl	S	Me		60	90	154–155	153–156[21]
10	H	S	Me		60	90	225–227	226–228 [22]
11	4-Cl	S	Et		45	93	190–192	188–190 [21]
12	4-OMe	S	Et		60	88	152–154	151–153 [22]
13	3-NO₂	S	Et		60	90	205–207	202–204 [23]