Table 10. Selected optimization condition for xanthene derivatives^a.

Entry	Catalyst (mol%)	Solvent	Temp. (°C)	Timeb (min)	Yieldc (%)
1	1	MeOH	70	60	35
2	1	Water	70	60	20
3	1	ACN	70	60	50
4	1	IPA	70	60	98
5	1	THF	70	60	40
6	1	CH2Cl2	70	60	30
7	1	MeOH	80	80	40
8	1	ACN	80	80	60
9	1	IPA	80	80	98
10	1	THF	80	80	50
11	1	CH2Cl2	80	80	40
12	1	IPA	25	90	—
13	0.5	IPA	70	60	60
14	2	IPA	70	60	85
15	—	IPA	70	180	10

^aReaction condition: benzaldehyde (1 mmol), dimedone (2 mmol).

^bReaction progress monitored by TLC.

^cIsolated yield.