Eutectic Salt Catalyzed Environmentally Benign and Highly Efficient Biginelli Reaction

Table 1

(SnCl₂)₂ChCl catalyzed green synthesis of dihydropyrimidinons.

Entry	Aldehyde (1)	Ketoester (2)	Yields (3) (%)	Mp (°C) found	Mp (°C) reported
1; 2; 3; 4; 5		2a; 2b; 2c; 2d; 2e	95; 95; 95; 84; 80	230–233; 207–209; 233; 179–182; 288–290	233–236 [23]; 206-207 [24]; 232–235 [29]; 180 [30]; 287–290 [31]
6; 7; 8; 9		2a; 2b; 2c; 2e	95; 94; 92; 90	202–205; 214–216; 232–234; Decom.	204-205 [32]; 213–215 [24]; 230–232 [33]; >300 [47]
10; 11; 12		2a; 2b; 2c	90; 92; 74	219; 221–224; 236–239	218–220 [34]; 220–222 [35]; 235–238 [8]
13; 14; 15		2a; 2b; 2c	85; 88; 80	166–168; 206–209; 180–182	166–168 [23]; 206-207 [36]; 178–180 [24]
16; 17		2a; 2b	80; 75	226–228; 160–162	225–227 [37]; 158–160 [38]
18; 19		2a; 2b	78; 82	238–240; 210–214	235–237 [24]; 208–211 [24]
20; 21		2a; 2b	90; 88	230–232; 188–190	229–231 [39, 40]; 185-186 [41]
22; 23		2a; 2f	68; 60	280–282; 226–229	279-280 [31]; 225-226 [42]
24; 25		2a; 2b	80; 74	204–206; 206–209	202–204 [43]; 206–208 [44]
26; 27		2a; 2b	84; 88	260–262; 250–252	255–257 [45]; 248–250 [46]
28		2b	80	224–227	226–228 [42]
29		2b	62	170	170-171 [42]