Research Article
CES as an Efficient Natural Catalyst for Synthesis of Schiff Bases under Solvent-Free Conditions: An Innovative Green Approach
Table 1
Physical characterization of Schiff bases.
| Entry | Substrates | Yield% | m.p. °C Found (reported) | | |
| 1 | 4-OH | 4-CH3 | 89 | 212–214 | 2 | 4-OCH3 | 4-CH3 | 90 | 93–95 | 3 | 4-NO2 | 4-CH3 | 98 | 121–125 (128–130) [42] | 4 | 4-N(CH3)2 | 4-CH3 | 90 | 90–94 | 5 | 2-OH,3-OCH3 | 4-CH3 | 94 | 210–212 | 6 | 4-OH | 4-OCH3 | 92 | 215–220 | 7 | 4-OCH3 | 4-OCH3 | 88 | 142–145 | 8 | 4-NO2 | 4-OCH3 | 98 | 68–72 | 9 | 4-N(CH3)2 | 4-OCH3 | 89 | 132–135 | 10 | 2-OH,3-OCH3 | 4-OCH3 | 96 | 110–112 | 11 | 4-OH | 4-Br | 81 | 188-189 | 12 | 4-OCH3 | 4-Br | 80 | 116–118 | 13 | 4-NO2 | 4-Br | 91 | 172–175 (176–178) [42] | 14 | 4-N(CH3)2 | 4-Br | 86 | 189–192 | 15 | 2-OH,3-OCH3 | 4-Br | 86 | 118-119 | 16 | 4-OH | 4-Cl | 83 | 230–232 | 17 | 4-OCH3 | 4-Cl | 80 | 90–94 (92) [42] | 18 | 4-NO2 | 4-Cl | 86 | 110–117 | 19 | 4-N(CH3)2 | 4-Cl | 81 | 178–182 | 20 | 2-OH,3-OCH3 | 4-Cl | 82 | 108–110 | 21 | 4-OH | 4-NO2 | 65 | 160–162 | 22 | 4-OCH3 | 4-NO2 | 59 | 69–71 | 23 | 4-NO2 | 4-NO2 | 81 | 112–116 | 24 | 4-N(CH3)2 | 4-NO2 | 84 | 178–182 | 25 | 2-OH,3-OCH3 | 4-NO2 | 40 | 146–149 |
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