Spatio-temporal release of biologically relevant small molecules provides exquisite control over the activation of receptors and signaling pathways. This can be accomplished via a photochemical reaction that releases the desired small molecule in response to irradiation with light. A series of biologically-relevant signaling molecules (serotonin, octopamine, capsaicin, N-vanillyl-nonanoylamide, estradiol, and tyrosine) that contain a phenol moiety were conjugated to the 8-bromo-7-hydroxyquinolinyl (BHQ) or 8-cyano-7-hydroxyquinolinyl (CyHQ) photoremovable protecting groups (PPGs). The CyHQ caged compounds proved sensitive toward 1PE and 2PE processes with quantum efficiencies of 0.2–0.4 upon irradiation at 365 nm and two-photon action cross sections of 0.15–0.31 GM when irradiated at 740 nm. All but one BHQ caged compound, BHQ-estradiol, were found to be sensitive to photolysis through 1PE and 2PE with quantum efficiencies of 0.30–0.40 and two photon cross sections of 0.40–0.60 GM. Instead of releasing estradiol, BHQ-estradiol underwent debromination.
生物学相关的小分子在时间和空间上的释放,为受体激活和信号通路的控制提供了精妙的方法。这可以通过光
化学反应来实现,即在光照下释放所需的小分子。一系列含有
酚基团的
生物学相关信号分子(包括
血清素、
章鱼胺、
辣椒素、N-荞麦基-壬酰胺、
雌二醇和
酪氨酸)被连接到
8-溴-7-羟基喹啉(BHQ)或8-
氰基-
7-羟基喹啉(CyHQ)这两种可光移除的保护基团(P
PGs)上。CyHQ笼状化合物在365 nm单光子激发和740 nm双光子激发下显示出敏感性,量子产率为0.2–0.4,双光子作用截面为0.15–0.31 GM。所有BHQ笼状化合物中,除了BHQ-
雌二醇,都对光解敏感,单光子和双光子激发的量子产率为0.30–0.40,双光子截面为0.40–0.60 GM。然而,BHQ-
雌二醇并未释放
雌二醇,而是发生了脱
溴反应。