Research Article
An Efficient Synthesis of Bis-indolylindane-1,3-diones, Indan-1,3-diones, and Indene-1,3(2H)-denies Using [Hbim]BF4 Ionic Medium
Table 2
Preparation of 5 in ionic liquid [Hbim]BF4.
| Entry | R1 | R2 | R3 | R4 | Product | Time (min) | Yield (%)a | Melting Point | Report, m.p. (°C) | Li. m.p. (°C) [Ref] |
| 1 | H | H | H | H | 5aa | 10 | 93 | 277–279 | 276–278 [9] | 2 | H | H | F | H | 5ab | 12 | 90 | 224–226 | Prepared for the first time | 3 | H | H | Br | H | 5ac | 8 | 92 | 275–277 | 274–276 [9] | 4 | H | CH3 | H | H | 5ad | 7 | 94 | 195–197 | Prepared for the first time | 5 | CH3 | H | H | H | 5ae | 5 | 95 | 183–185 | 182–184 [9] | 6 | H | H | H | CH3 | 5ba | 7 | 93 | 217–219 | 218–220 [9] | 7 | H | H | F | CH3 | 5bb | 7 | 92 | 210–212 | Prepared for the first time | 8 | H | H | Br | CH3 | 5bc | 7 | 95 | 219–221 | Prepared for the first time | 9 | H | CH3 | H | CH3 | 5bd | 5 | 97 | 205–207 | 204–206 [9] | 10 | CH3 | H | H | CH3 | 5be | 3 | 95 | 171–173 | 170–172 [9] | 11 | H | H | H | Cl | 5ca | 10 | 94 | 228–230 | Prepared for the first time | 12 | H | H | F | Cl | 5cb | 15 | 91 | 199–201 | Prepared for the first time | 13 | H | H | Br | Cl | 5cc | 8 | 93 | 223–225 | Prepared for the first time | 14 | H | CH3 | H | Cl | 5cd | 7 | 94 | 253–255 | Prepared for the first time | 15 | CH3 | H | H | Cl | 5ce | 5 | 95 | 185–187 | 186–188 [9] |
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Yield refers to pure products after crystallization.
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