Halogenated reagents and triphenylphosphine for the syntheses of amides, esters and sulfonamides

Abstract

The utilization of Cl[subscript 3]CCONH[subscript 2] and PPh[subscript 3] could be applied to prepare nine benzamides whose structures are related to DEET. This reagent could also be successfully utilized to synthesize esters. Examining the scope of the reaction revealed that this reagent was suitable for primary and secondary alcohols while tertiary alcohol did not proceed well. However, tertiary carboxylic acid could transform efficiently to ester. The mechanistic studies supported by IR, [superscript 1]H- AND [superscript 13]C-NMR spectral data clearly exhibited that these reactions occur via acid chlorides. The new methodology for the preparation of sulfonamides using halogenated reagents and PPh[subscript 3] was in addition disclosed. The effects of type of halogenated reagents, amount of reagents, type of bases and solvent system were investigated to optimize reaction conditions. Cl[subscript 3]CCN in combination with PPh[subscript 3] approved to be a highly reactive reagent for conversion of sulfonic acids to the corresponding sulfonyl chlorides in refluxing CH[subscript 2]Cl[subscript 2] within 1 hour. Upon treating with amines, the corresponding benzenesulfonamides were achieved in good to excellent yields. This reaction worked well for all amines selected: primary aliphatic, secondary aliphatic and aromatic amines