Green catalytic synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes using recyclable mesoporous zirconia modified with tungstophosphoric acid

Figures & data

short-legendScheme 1. Synthesis of aryl-14H-dibenzo[a,j]xanthenes with ZrTPA60BT100 as catalyst.

Table 1. Reaction between 2-naphthol and benzaldehyde under different conditions.

Entry	Catalizador	Temperature (°C)	Time (h)	Yield^a (%)
1	Without catalyst	80	1.5	–
2		100	1.5	–
3		120	1.5	15
4		130	1.5	32
5		130	5	30
6	TPA bulk^b	80	5	–
7		100	1	Traces
8		100	3	10
9		130	1	90
10	ZrTPA60BT100 ^c	80	5	–
11		100	3	10
12		120	2	82
13		130	1	99
14		130^d	1	98
15		130^d	1	98
16		130^d	1	96
^aThe yields refer to the isolated product.
^bTPA bulk=50 mg.
^cZrTPA60BT100=84 mg.
^dFirst, second, and third reuse.

Table 2. Synthesis of aryl-14H-dibenzo[a,j]xanthenes with ZrTPA60B_T100 as catalyst.^a

Entry	Aromatic aldehyde	Time (h)	Yield^b (%)
1	Benzaldehyde	1	99
2	4-Methylbenzaldehyde	1	94
3	4-Methoxybenzaldehyde	1	93
4	4-Florobenzaldehyde	2	98
5	4-Chlorobenzaldehyde	2	96
6	4-Bromobenzaldehyde	2	93
7	2-Chlorobenzaldehyde	2	89
8	2,4,6-Trimethoxybenzaldehyde	5	60
9	2-Naphthaldehyde	3	78
10	1-Naphthaldehyde	3	81
^aReaction conditions: aldehyde, 1.2 mmol; 2-naphthol, 2 mmol; catalyst: ZrTPA60BT100, 85 mg, 130 °C.
^bThe yields refer to the isolated product.