Design and application of a new julolidine-based photolabile protecting group

Photolabile protecting groups (PPGs) are invaluable tools for protecting a variety of functionalities and serve as alternatives to protecting groups that need chemical cleavage. PPGs are mainly classified into 3 categories namely, 2-nitrobenzyl type PPGs, coumarin-based PPGs, and benzyl type PPGs which have been designed by Wang and co-workers based on the meta effect and computational study observations. This work describes the design and synthesis of a julolidine-based benzyl type PPG 4 and the analysis of its reaction intermediates. The julolidine PPG 4 is applied for the protection of alcohols as carbonates, amines as carbamates, carboxylic acids as esters, and hydroxamic acid. Analysis of the photolyzed samples by HPLC has also been conducted.