R. Schwyzer, W. Rittel
1961
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0
Influential Citations
102
Citations
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Journal
Helvetica Chimica Acta
Abstract
For the synthesis of β1–19 corticotropin-Glu5-γ-amide1) a derivative of lysine was needed involving a blocking group on Nϵ easily removable by mild acid treatment. Nϵ-t-Butoxycarbonyl-L-lysine was synthesized and found to be a very versatile compound. The Nϵ-t-butoxycarbonyl group is readily removed by trifluoroacetic acid and by aqueous HCI, it is not cleaved by anhydrous or aqueous acetic acid in the experimental conditions described here. This allows its use in conjunction with the N-trityl group which is easily hydrolysed by aqueous acetic acid. Needless to point out, it may also be used along with the carbobenzoxy or p-phenylazocarbobenzoxy groups which may preferentially be removed by catalytic hydrogenation. A number of derivatives and peptides of Nϵ-t-butoxycarbonyl-L-lysine are described, among these are trityl·Lys(BOC)-Lys(BOC)·OH7) and PZ·Lys(BOC)-Pro-Val-Gly·OH, both intermediates in the synthesis of the nonadecapeptide with high corticotropic activity1). The derivatives described here should also be useful for the preparation of ϵ-peptides of lysine.