Preparation of N(π)-alkyl- histamine and histidine derivatives through efficient alkylation followed by deprotection using activated silica gel

Efficient N(π)-alkylation of l-histidine and histamine derivatives through employment of N(τ)-trityl-protection was achieved and regioselective removal of the N(τ)-trityl group in the presence of either Boc- or trityl-protected primary amine was effected based on a mild hydrolysis mediated by activated silica gel with 0.1–0.2% trifluoroacetic acid.