TABLE 2.

Yield, TON, TOF, melting points, and references for the prepared 14H-dibenzoxanthene derivatives.

	R1	R2	Yield (%) b	TON c	TOF d (Sec−1)	m.p.	Ref.
2a	H	C2H5	53	5.3	2/9 × 10−2	128–130	Karimi-Jaberi and Keshavarzi (2010)
2b	H	n-C3H7	62	6.2	3/4 × 10−2	151–152	Kumar et al. (2010)
2c	H	i-C3H7	59	5.9	3/3 × 10−2	151–152	Kumar et al. (2010)
2d	H	C5H11	64	6.4	3/6 × 10−2	97–98	Wang et al. (2014)
2e	H	C6H5	60	6.0	3/3 × 10−2	191–192	Kumar et al. (2010)
2f	H	3-Me-C6H4	55	5.5	3/1 × 10−2	204–206	Ghasemnejad-Bosra and Forouzani, (2011)
2g	H	4-Me-C6H4	59	5.9	3/3 × 10−2	234–237	Kumar et al. (2010)
2h	H	4-Cl-C6H4	65	6.5	3/6 × 10−2	291–292	Kumar et al. (2010)
2i	H	4-OMe-C6H4	57	5.7	3/2 × 10−2	212–214	Kumar et al. (2010)
2j	H	4-NO2-C6H4	76	7.6	4/2 × 10−2	328–329	Wang et al. (2014)
2k	H	3,4-di-OMe-C6H4	48	4.8	2/7 × 10−2	195–196	Bhattacharya et al. (2009)
2l	H	2-Furyl	58	5.8	3/2 × 10−2	198–200	Shirini and Khaligh, (2012)
2m	H	2-Thiophenyl	61	6.1	3/4 × 10−2	179–181	Osyanin et al. (2015)
2n	H	2-Naphtyl	72	7.2	4/0 × 10−2	195–198	Shirini and Khaligh, (2012)
2o	Br	C2H5	50	5.0	2/8 × 10−2	134–136	Vaughan and Jha, (2009)
2p	Br	n-C3H7	55	5.5	3/1 × 10−2	152–155	Wang et al. (2014)
2q	Br	i-C3H7	61	6.1	3/4 × 10−2	180–183	Vaughan and Jha, (2009)
2r	Br	C5H11	58	5.8	3/2 × 10−2	oil	Wang et al. (2014)
2s	Br	C6H5	62	6.2	3/4 × 10−2	245–248	Wang et al. (2014)
2t	Br	3-Me-C6H4	57	5.7	3/2 × 10−2	181–183	Pawar et al. (2014)
2u	Br	4-Me-C6H4	59	5.9	3/3 × 10−2	250–251	Wang et al. (2014)
2v	Br	4-Cl-C6H4	57	5.7	3/2 × 10−2	290–292	Wang et al. (2014)
2w	Br	4-OMe-C6H4	55	5.5	3/1 × 10−2	255–260	Pawar et al. (2014)
2x	Br	4-NO2-C6H4	75	7.5	4/2 × 10−2	304–306	Wang et al. (2014)
2y	Br	3,4-di-OMe-C6H4	51	5.1	2/8 × 10−2	184–186	Pawar et al. (2014)

^a The reaction conditions for the model reaction (1 mmol benzaldehyde and 2 mmol β-naphthol): 10 mol% catalyst, 10 ml ethanol, reflux, 3 h

^b Isolated yield

^c Turnover number = the moles of desired product/the moles of catalyst

^d Turnover frequency = TON/the reaction time (in seconds)