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Indian Journal of Chemistry -Section B (IJC-B) >
IJC-B Vol.47B [2008] >
IJC-B Vol.47B(02) [February 2008] >
| Title: | p-TsOH Catalyzed regioselective synthesis of 8,8'-methylene-bis-4- oxo-dihydrochromeno [4,3-c]pyrazoles |
| Authors: | Reddy, Ch Sanjeeva
Nagaraj, A |
| Keywords: | p-TsOH, regioselective synthesis
8,8'-methylene-bis-4-oxo-1,4-dihydrochromeno[4,3-c]pyrazoles
8,8-methylene-bis-2,4-dihydrochromeno[4,3-c]pyrazoles |
| Issue Date: | Feb-2008 |
| Publisher: | CSIR |
| Abstract: | The ethyl-5-[3-(ethoxycarbonyl)-4-hydroxybenzyl]- 2-hydroxybenzoate 3 is prepared by the usual esterification of 5-(3-carboxy-4-hydroxybenzyl)-2-hydroxy benzoic acid 2. Compound 3 on reacting with ethyl acetoacetate yields 3-acetyl-6-[(3-acetyl-4-hydroxy-2-oxo-2H-6- chromenyl)methyl]-4-hydroxy-2H-2-chromenone 4. The regioselective conversion, by cyclizing the hydrazone 5 of compound 4 to either 8,8'-methylene-bis-4-oxo-1,4-dihydrochromeno [4,3-c]pyrazoles 6 with p-toluene sulfonic acid in refluxing xylene or 8,8'-methylene-bis-4-oxo-2,4-dihydro chromeno[4,3-c]pyrazoles 7 with corresponding hydrazine hydrochloride in refluxing acetic acid is described. |
| Page(s): | 319-324 |
| ISSN: | 0376-4699 |
| Source: | IJC-B Vol.47B(02) [February 2008]
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