PEG-400 Mediated an Efficient Green Synthesis of Isoxazolyl Indole-3-Carboxylic Acid Esters via Nentizescu Condensation Reaction and Their Anti-Inflammatory and Analgesic Activity

摘要

abstract_textpPolyethylene glycol-400 (PEG-400) has been discovered as an efficient and eco-friendly reaction medium for the synthesis of new isoxazolyl indole-3-carboxylic acid esters 11 from 4-amino3-methyl-5-styrylisoxazoles 7. Compounds 7 on treatment with beta-keto ester 8 afforded the corresponding isoxazolylamino-2butenoates 9 at ambient temperature in PEG-400. The Nentizescu condensation of compounds 9 with 1,4-benzoquinone 10 to give the title compounds isoxazolyl indole-3craboxylic acid esters 11 under PEG-400. Structures of compounds 9 and 11 were established on the basis of IR, (HNMR)-H-1, (CNMR)-C-13 and HRMS analysis. All the final compounds 11a-s were evaluated for their anti-inflammatory and analgesic activities. Among the compounds tested, the compounds 11b, 11g, 11n, 11 o, 11p and 11 s exhibited significant anti-inflammatory and potent analgesic activities as that of standard drugs. The advantages of this protocol are: operational simplicity, environmental safety, broad substrate scope, excellent functional group tolerance, and good yields. The PEG-400 can be recovered and reused./p/abstract_text