Table 1.

Optimized reaction condition between benzosuberone 1 and arylhydrazonal 2a.

Entry	Solvent	Temp (°C)	Time	Yield (%)
1	DMF	Reflux	12 h	–
2	1,4-dioxane	Reflux	12 h	–
3	CH3CN	Reflux	12 h	–
4	EtOH	Reflux	12 h	–
5	propanol	Reflux	12 h	–
6	AcOH	Reflux	4 h	41a
7	AcOH	MW (sealed tube) (120 °C, 250 W)	25 min	63b
8	AcOH	MW (sealed tube) (130 or 150 °C, 250 W)	30 min	69b
9	AcOH	Q-tube (150 °C)	30 min	85c
10	AcOH	Q-tube (155 °C)	30 min	91c
11	AcOH	Q-tube (160 °C)	30 min	95c
12	AcOH	Q-tube (165 °C)	30 min	98c
13	AcOH	Q-tube (170 °C)	30 min	98c

Reaction conditions: ^aA mixture of benzosuberone (1) (5 mmol), 3-oxoarylhydrazonal 2a (5 mmol) and ammonium acetate (10 mmol) in acetic acid (10 ml) was refluxed under normal pressure for 4 h.

^bA mixture of benzosuberone (1) (2 mmol), 3-oxoarylhydrazonal 2a (2 mmol) and ammonium acetate (4 mmol) in acetic acid (5 ml) was introduced to the microwave tube (10 ml) and irradiated by MW (250 W) at the reported temperature and time.

^cA mixture of benzosuberone (1) (5 mmol), 3-oxoarylhydrazonal 2a (5 mmol) and ammonium acetate (10 mmol) in acetic acid (10 ml) was introduced to the Q-tube (35 ml) and heated in an oil bath at the reported temperatures for 30 min.