Resin-Bound Thiophenol Esters with n-Butylamine

1 Cleavage of Resin-Bound Thiophenol Esters with n-Butylamine 

The reactivity of seven resin-bound thiophenol esters toward n.-butylamine (41) varied depending on their structures. The reaction of aromatic thiophenol esters (resins (34-36) took about 24 h to complete as indicated by the complete disappearance of carbonyl band in single bead FTIR spectra. On the other hand, the same reaction with alkyl thiophenol esters (resins 38-40) went to completion in less than 8 hours. The reaction with benzimidazolecarboxylic thiophenol ester (resin (37) was the fastest, finished in 3 h. 

When n-butylamine was used for cleavage, the rate of the alkyl thiophenol esters were approximately 13 times faster than that of the aromatic thiophenol esters. The rate of benzimidazolecarboxylic thiophenol esters was 45 times faster than that of aromatic thiophenol esters and 3 times faster than that of the alkyl thiophenol esters. 

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