Photochemical Cleavage of Benzylic C–N Bond To Release Amines

The 3-(diethylamino)­benzyl (DEABn) group has been studied for releasing primary, secondary, and tertiary amines by direct photochemical breaking of the benzylic C–N bond. While photochemical release of primary and secondary amines provides high yields in methanol, release of tertiary amines in MeCN/water can improve yields and reduce the undesired dealkylation side reaction

Structurally Simple Benzylidene-Type Photolabile Diol Protecting Groups

Two structurally simple photolabile protecting groups for releasing 1,2- and 1,3-diols have been developed. The diols can be protected in high yields and released from their corresponding acetals with high chemical efficiency

Photochemical Formation and Cleavage of C–N Bond

A new photochemical method of C–N bond formation has been developed. A properly substituted trityl alcohol can cleave the benzylic C–O bond and replace it with a C–N bond which is stable under the irradiation conditions. The C–N bond can then be photochemically cleaved with the same light source when the nitrogen is protonated

Synthesis and Evaluation of QS-21-Based Immunoadjuvants with a Terminal-Functionalized Side Chain Incorporated in the West Wing Trisaccharide

Three QS-21-based vaccine adjuvant candidates with a terminal-functionalized side chain incorporated in the west wing trisaccharide have been synthesized. The terminal polar functional group serves to increase the solubility of these analogues in water. Two of the synthetic analogues have been shown to have adjuvant activity comparable to that of GPI-0100. The stand-alone adjuvant activity of the new synthetic analogues again confirmed that it is a feasible way to develop new saponin-based vaccine adjuvants through derivatizing at the west wing branched trisaccharide domain. Inclusion of an additional polar functional group such as a carboxyl group (as in <b>3x</b>) or a monosaccharide (as in <b>4x</b> and <b>5x</b>) is sufficient to increase the water solubility of the corresponding synthetic analogues to a level comparable to that of GPI-0100 and suitable for immunological studies and clinical application. The structure of the incorporated side chain has a significant impact on the adjuvant activity in terms of the magnitude and nature of the host’s responses