The reaction of 2-aminobenzothiazole, 4-nitrobenzaldehyde, and ethyl acetoacetate in the presence of Fe₃O₄@nano-cellulose/Cu(ii) under various conditions^a.

Entry	Solvent	Catalyst (g)	Condition	Time (h)	Yieldb (%)
1	—	—	80 °C	7 h	30
2	—	CuCl2	80 °C	3h	69
3	—	Fe3O4	70 °C	3h	37
4	—	Fe3O4@nano-cellulose	80 °C	4 h	41
5	C2H5OH	—	R. T	7 h	—
6	C2H5OH	Catalyst (0.04)c	R. T	3 h	35
7	C2H5OH	Catalyst (0.04)c	Reflux	3 h	57
8	H2O	Catalyst (0.04)c	Reflux	3 h	42
9	CH3OH	Catalyst (0.04)c	Reflux	3 h	51
10	—	Catalyst (0.04)c	R. T	3 h	43
11	—	Catalyst (0.04)c	70 °C	1 h	85
12	—	Catalyst (0.05)c	80 °C	0.5	93
13	—	Catalyst (0.04)c	80 °C	0.5	97
14	—	Catalyst (0.03)c	80 °C	0.5	97
15	—	Catalyst (0.02)c	80 °C	0.5	84
16	—	Catalyst (0.03), 2thrunc	80 °C	0.5	93
17	—	Catalyst (0.03), 3rdrunc	80 °C	0.5	88
18	—	Catalyst (0.03), 4thrunc	80 °C	0.5	83

^aThe amount ratio of 2-aminobenzothiazole (mmol), 4-nitrobenzaldehyde (mmol) and ethyl acetoacetate (mmol) are equal to 1 : 1 : 1.

^bIsolated yield.

^cFe₃O₄@ nano-cellulose/Cu(ii).