One-pot multicomponent synthesis of polyhydroquinolines under catalyst and solvent-free conditions

Figures & data

short-legendScheme 1. Synthesis of polyhydroquinolines.

Table 1. Synthesis of polyhydroquinoline derivatives.

					MP (°C)
Entry	Aldehyde	Product	Time (min)	Yield^a (%)	Found	Reported
1		4a	3	88	201–203	202–204 (9)
2		4b	3	82	260–262	261–262 (9)
3		4c	4	82	259–261	258–260 (8)
4		4d	3	85	247–249	247–248 (8)
5		4e	6	81	207–209	207–208 (8)
6		4f	5	81	236–238	238–240 (8)
7		4g	6	78	221–223	220–222 (8)
8		4h	4	80	250–252	252–253 (9)
9		4i	3	86	185–187	185–186 (9)
10		4j	6	81	200–202	202–204 (9)
11		4k	5	84	241–243	243–244 (8)
12		4l	3	84	215–217	–
13^b		4m	3	83	251–252	–
^aIsolated yields.
^bThe reaction was conducted with 4-chlorobenzaldehyde, dimedone, methylacetoacetate and ammonium acetate.

Table 2. Comparison of the present protocol with recently reported methods.

Entry	Aldehyde	Present method		Reported method (12)		Reported method (13)
		Time	Yield (%)^a	Time	Yield (%)^b	Time	Yield (%)^c
1		3 min	88	1 min	95	1 min	95
2		3 min	84	–	–	–	–
3		3 min	85	2 min	90	2 min	97
^aPresent reaction conditions: 90°C, 240 W MW (without any solvent and catalyst).
^bReported reaction conditions: Ni nanoparticle (10 mol%), 540 W MW.
^cReported reaction conditions: Glycine (10 mol%) in acetonitrile solvent, 80°C, 180 W MW.