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 |
|
|
