Table 4.

Three-component synthesis of different 2-amino-5,10-dihydro-5,10-dioxo-4H-benzo[g]chromene-3-carbonitrile (8a–j) via condensation of malononitrile (1), various aldehydes (2) and 2-hydroxy-1,4-naphthoquinone (7) in the presence of CuFe₂O₄@starch at room temperature.

entry	aldehyde	product	time (min)	isolated yields (%)	M.p. (Obsd) (°C)	M.P. (Lit) (°C)
1	4-chlorobenzaldehyde	8a	25	97	245–247	243–244 [11]
2	2-chlorobenzaldehyde	8b	30	90	240–242	238–240 [39]
3	4-nitrobenzaldehyde	8c	28	89	229–232	232–234 [11]
4	2-nitrobenzaldehyde	8d	33	87	246–248	242–244 [39]
5	4-hydroxybenzaldhyde	8e	37	89	263–265	258–260 [11]
6	3,4-dimethoxybenzaldehyde	8f	40	93	275–277	270–272 [39]
7	4-methoxybenzaldehyde	8g	38	87	260–263	257–259 [40]
8	4-methylbenzaldehyde	8h	45	88	259–262	254–257 [40]
9	4-fluorobenzaldehyde	8i	28	91	290–293	286–288 [39]
10	4-bromoenzaldehyde	8j	30	95	242–244	249–251 [11]