SOLID PHASE SYNTHESIS OF N-SUBSTITUTED-4- (TRIFLUOROMETHYL)-C-PHENYL ISOXAZOLIDINE, ISOXAZOLINE DERIVATIVES AND THEIR FURTHER APPLICATIONS IN PEPTIDE SYNTHESIS
N-Substituted-4-(Trifluoromethyl)-C-Phenyl nitrones have been employed for the synthesis of some newtrifluoromethyl cycloadducts via (3 + 2) cycloaddition reactions using a mechanochemical procedure (ball-milling). This solvent-free procedure in the presence of sodium bicarbonate showed a remarkably faster reaction rate, better yields, as well as easier workup procedure for the isolation of trifluoronitrones and trifluoro cycloadducts comparedto microwave-induced cycloaddition procedures. A few trifluoro-cycloadducts (4,5-dicarboxylic acid substitutedisoxazolines) have also been successfully employed in the synthesis of new trifluoro di-peptides. This proceduremay open a new avenue for the synthesis of dipeptides with excellent yield. We found from the preliminary studiesfew trifluoro-cycloadducts and di-peptides are capable of exhibiting anticancer activities. Though nitrones areusually unstable and utilised in in situ reactions, N-Substituted-4-(Trifluoromethyl)-C-Phenyl nitrones reportedhereare stable and characterizable.
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