Benzoic Acid-Derived Loop Diuretics

The loop diuretics furosemide (Fig. 4.12,2), bumetanide (Fig. 4.12,3), and piretanide include a benzoic acid residue, which suggests a favored negative ionization of these drugs by deprotonation of the carboxyl function. The product ion mass spectrum of m/z 363 of bumetanide (3-butylamino-4-phenoxy-5-sulfamoylbenzoic acid, Fig. 4.13b), contains 

Substance Class Representative Compound MoIWt (Da) Precursor Ion m/z) Product Ions m/z)  

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