Table 2.

Synthesis of compounds 4^a

Entry	1	R	Time (h)	Yield (%)b
1	1a	Ph	6	4a (68)
2	1b	3-NO2C6H4	7	4b (65)
3	1c	3,4-(MeO)2C6H3	6.5	4c(72)
4	1d	3-MeC6H4	7	4d (52)
5	1e	4-MeC6H4	6	4e (73)
6	1f	3,4-(Me)2C6H3	7.5	4f (55)
7	1g	4-ClC6H4	5	4g (74)
8	1h	4-BrC6H4	5.5	4h (71)
9	1i	3-MeOC6H4	6	4i (64)
10	1j	4-NO2C6H4	5.5	4j (71)

^aThe reactions were carried out with 1 (1 mmol), pyridine(0.1 mL), acetic anhydride (1 mL) under reflux at 85 °C.

^bAll the yields were isolated yields.