• Photosensitive protecting reagent for alcohols, acids, phenols etc., cf 4,5-Dimethoxy-2-nitrobenzyl alcohol, L00719. Bis(2-nitrobenzyl) acetals of carbonyl compounds, prepared by acetalization in the presence of 2,2-dimethoxypropane, are cleaved photochemically: J. Chem. Soc., Chem. Commun., 1828 (1985). For reviews of photoremovable groups in organic synthesis, see: Synthesis, 1 (1980); Org. Photochem., 9, 225 (1987).