BHA resin turned out to be not sufficiently acid-labile for obtaining peptide amides with sterically hindered C-termini (e.g. Phe, Leu) applying standard cleavage conditions. Introduction of a 4-methyl substituent sufficiently increased the acid-lability of the peptide-resin linkage. Cleavage can be achieved with HF, trifluoromethanesulfonic acid or tetrafluoroboronic acid/thioanisole in TFA using scavengers such as m-cresol and ethanedithiol. This resin has been employed by Pei et al. in the synthesis of quinolinones from β-lactams, and in the conversion of linear peptide amides to cyclic ureas or thioureas.