Sulfonylhydrazide resin

In 2001, Sarko and coworkers disclosed the synthesis of an 800-membered solution-phase library of substituted prolines based on multicomponent chemistry (Scheme 6.187) [349]. The process involved microwave irradiation of an a-amino ester with 1.1 equivalents of an aldehyde in 1,2-dichloroethane or N,N-dimethyl-formamide at 180 °C for 2 min. After cooling, 0.8 equivalents of a maleimide dipo-larophile was added to the solution of the imine, and the mixture was subjected to microwave irradiation at 180 °C for a further 5 min. This produced the desired products in good yields and purities, as determined by HPLC, after scavenging excess aldehyde with polymer-supported sulfonylhydrazide resin. Analysis of each compound by LC-MS verified its purity and identity, thus indicating that a high quality library had been produced. 

To capture electrophilic substrates such as acid halides, aldehydes, alkyl halides, isocyanates, and isothiocyanates, a variety of nucleophilic resins are commonly used. Some commercially available and representative examples are tris-(2-aminoethyl)amine (9), thiophenol (10), sulfonylhydrazide (11), triphenylphosphine (12), and methylthiourea (13) polymer resins (Fig. 6). 

Alkene Reduction. Sulfonylhydrazides deconpose into di-imide and sulfonic acid when heated. For this reason, they have heen utilized in the reduction of unsaturated compounds. When 2,4,6-triisopropylbenzenesulfonylhydrazide (TPSH) is used, the diimide can be generated at room temperature in the presence of base to reduce mono- or disubstituted double bonds selectively in the presence of trisuhstituted alkenes (eq 15). This reduction method tolerates sensitive groups such as esters, ketones, or organocohalt complexes and has heen applied in the preparation of polymers and in the synthesis of natural products (eq 16). This reagent was not effective in the reduction of resin-hound cyclic peptides. ... 

Toluenesulfonamide Resin n Resins made by the interaction of toluene sulfonamide and formaldehyde. p-Toluenesulfonylhydrazide n A blowing agent similar to benzene-sulfonylhydrazide, but having higher melting and decomposition temperatures. 

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