MFe₂O₄@PDA@BuSO₃H (0.05 g) as catalyzed multi-component domino reactions for the one-pot efficient synthesis of benzopyrazine derivatives containing 2-aminoimidazole.

Entry	R1	R2	Ar	Compound	Time (h)	Mp (°C)	Yield %
1	Br	H	Phenyl	5a	3	251–253	87
2	H	Br	Phenyl	5b	3	252–254	85
3	Br	H	p-F-phenyl	5c	2	250–253	90
4	H	Br	p-F-phenyl	5d	3	254–257	89
5	Br	H	p-Br-phenyl	5e	2	255–258	90
6	H	Br	p-Br-phenyl	5f	3	257–259	89
7	Br	H	2-Naphtyl	5g	3	274–276	88
8	H	Br	2-Naphtyl	5h	2	273–276	87
9	Br	H	p-OMe-phenyl	5i	3	243–246	89
10	H	Br	p-OMe-phenyl	5j	2	241–243	88
11	Br	H	p-Cl-phenyl	5k	2	238–240	89
12	H	Br	p-Cl-phenyl	5l	2	238–240	87
13	Br	H	p-biphenyl	5m	2	257–260	85
14	H	Br	p-biphenyl	5n	2	258–260	84
15	Br	H	p-Me	5o	3	247–249	84
16	H	Br	p-Me	5p	3	230–232	82