Entry Catalyst Amount of catalyst (mol%) Temp. (°C) Time (h) Yield (%)a Ref. 1 p-TSA 10 125 4 89 9c 2 Sulfamic acid 10 125 8 93 17 3 Poly(4-vinylpyridinium) hydrogen sulfate 2 100 55 min 94 22a 4 Succinimide-N-sulfonic acid 5.6 80 35 min 94 22c 5 Sulfuric acid 10 mg 110-115b 1.5 91 31 6 Cellulose sulfuric acid 80 mg 110-115 1.5 81 31 7 Montmorillonitr K10 300 mg 120 3 75 32 8 Amberlyst-15 10 mg 125 2 94 33 9 Silica sulfuric acid 80 mg 110-115 1.5 89 34 10 Dowex-50W 100 mg 100 1.5 78 35 11 NSPVPHS 10 mg 60 15 min 94 This work 12 NSPVPHS 10 mg Utrasonic method  at r.t. 5 min 95 This work a Isolated yields b Solvent: acetic acid

Table 5: Comparison of our results with the results obtained by other groups in the synthesis of 14-(phenyl)-14H-dibenzo[a,j] xanthene.