Carboxylic acids, functional derivatives sulfonamides

The Kenner sulfonamide-based SC linker 1.27 was supported on PS resin (84) allowing the attachment of carboxylic acids or amino acids to the sulfonamide function. After synthetic elaboration, treatment with diazomethane produces the A-methylacylsulfonamide, which can be cleaved with nucleophiles such as 0.5 N NHs-dioxane or hydrazine-MeOH, 0.5 N NaOH, releasing amides, hydrazides, or carboxylic acids, respectively. A modification using iodoacetonitrile produces the more labile A-cyanomethyl derivative, which can be cleaved completely with stoichiometric amounts of amines to release the corresponding amides into solution. 

The carboxylic function of active compounds has been changed to direct derivatives such as hydroxamic acids R— CO—NH—OH, acyl-cyanamides R—CO—NH—CN and acyl-sulfonamides R—CO—NH—SO2—R to planar acidic heterocycles such as tetrazoles, hydroxy-isoxazoles, etc., or even to non-planar sulfur- or phosphorus-derived acidic functions (Table 13.8). 

Acidity of Amides, Imides, and Sulfonamides Characteristic Reactions Reaction with Water Hydrolysis Reaction with Alcohols Reactions with Ammonia and Amines Reaction of Acid Chiorides with Salts of Carboxylic Acids Interconversion of Functional Derivatives Reactions with Organometallic Compounds 18.10 Reduction... 

Serum albumin, in addition to its important osmotic function, shows specific powers of reversible combination with a large variety of molecules. These include the anions and cations of many acid and basic dyes the anions of fatty acids and alkyl sulfonic acids, of many aromatic carboxylic acids and acetylated amino acids sulfonamide derivatives many types of naphthoquinone derivatives and a variety of other compounds. All these substances show a very strong preferential tendency to combine with albumin, rather than with the other proteins of... 

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