A series of fluorophore-labeled S-nitrosothiols were synthesized, and their fluorescence enhancements upon removal of the nitroso (NO) group were evaluated either by transnitrosation or by photolysis. It was shown that, with a suitable alkyl linker, the fluorescence intensity of dansyl-labeled S-nitrosothiols could be enhanced up to 30-fold. The observed fluorescence enhancement was attributed to the intramolecular energy transfer from fluorophore to the SNO moiety. Ab initio density functional theory (DFT) calculations indicated that the "overlap" between the SNO moiety and the dansyl ring is favored because of their stabilizing interaction, which was in turn affected by both the length of the alkyl linker and the rigidity of the sulfonamide unit. In addition, one of the dansyl-labeled S-nitrosothiols was used to explore the kinetics of S-nitrosothiol/thiol transnitrosation and was evaluated as a fluorescence probe of S-nitrosothiol-bound NO transfer in human umbilical vein endothelial cells.
A series of fluorophore-labeled S-nitrosothiols were synthesized, and their fluorescence enhancements upon removal of the nitroso (NO) group were evaluated either by transnitrosation or by photolysis. It was shown that, with a suitable alkyl linker, the fluorescence intensity of dansyl-labeled S-nitrosothiols could be enhanced up to 30-fold. The observed fluorescence enhancement was attributed to the intramolecular energy transfer from fluorophore to the SNO moiety. Ab initio density functional theory (DFT) calculations indicated that the "overlap" between the SNO moiety and the dansyl ring is favored because of their stabilizing interaction, which was in turn affected by both the length of the alkyl linker and the rigidity of the sulfonamide unit. In addition, one of the dansyl-labeled S-nitrosothiols was used to explore the kinetics of S-nitrosothiol/thiol transnitrosation and was evaluated as a fluorescence probe of S-nitrosothiol-bound NO transfer in human umbilical vein endothelial cells.
Sulfur participation in solvolysis involving four-membered ring intermediates
作者:Ernest L. Eliel、William H. Pearson、Linda M. Jewell、Anthony G. Abatjoglou、William R. Kenan
DOI:10.1016/s0040-4039(01)85465-4
日期:1980.1
Neighboring group participation via four-membered ring intermediates resulting in complete rearrangement occurs in the methanolysis of R1R2C(SCH2C6H5)CH2CH(R3)OTs when R1=R2=R3=Me and when R1=R2=Me, R3=H. No rearrangement is found for R1=R2=R3=H or R1=R2=H, R3=Me. The case of R1=Me, R2=R3=H is intermediate.
当R 1 = R 2 = R 3 = Me时,在R 1 R 2 C(SCH 2 C 6 H 5)CH 2 CH(R 3)OTs的甲醇分解中,经由四元环中间体的相邻基团参与导致完全重排。当R 1= R 2= Me时,R 3= H。对于R 1= R 2= R 3= H或R 1= R 2= H,R 3= Me ,没有发现重排。R 1 = Me,R 2的情况= R 3 = H是中间的。
Neighboring group participation by sulfur involving four-membered-ring intermediates (RS-4)
作者:Ernest L. Eliel、David E. Knox
DOI:10.1021/ja00296a019
日期:1985.5
On etudie les produits de methanolyse et de trifluoroethanolyse ainsi que les vitesses de methanolyse d'un certain nombre de p-toluenesulfonates d'alkylthio-3 et d'arylthio-3 propyle substitues sur la chaine
On etudi les produits demethylyse et de trifluoroethanolyse ainsi que les vitesses demethylyse d'un some nombre de p-甲苯磺酸 d'alkylthio-3 et de d'arylthio-3 propyle substitues