13509-34-7Relevant articles and documents
Short Total Synthesis of [15N5]-Cylindrospermopsins from 15NH4Cl Enables Precise Quantification of Freshwater Cyanobacterial Contamination
Mailyan, Artur K.,Chen, Joanna L.,Li, Weiwei,Keller, Arturo A.,Sternisha, Shawn M.,Miller, Brian G.,Zakarian, Armen
supporting information, p. 6027 - 6032 (2018/05/05)
Fresh water cyanobacterial algal blooms represent a major health risk because these organisms produce cylindrospermopsin, a toxic, structurally complex, zwitterionic uracil-guanidine alkaloid recognized by the EPA as a dangerous drinking water contaminant. At present, the ability to detect and quantify the presence of cylindrospermospin in water samples is severely hampered by the lack of an isotopically labeled standard for analytical mass spectrometry. Herein, we present a concise, scaled total synthesis of 15N cylindrospermosin from 15N ammonium chloride, which leverages a unique stereoselective intramolecular double conjugate addition step to assemble the tricyclic guanidine core. In addition to providing the first pure isotopically labeled probe for precise quantification of this potent biotoxin in fresh water sources, our results demonstrate how unique constraints associated with isotope incorporation compel novel solutions to synthesis design.
An Unconventional Mechanistic Insight into SCF3 Formation from Difluorocarbene: Preparation of 18F-Labeled α-SCF3 Carbonyl Compounds
Zheng, Jian,Cheng, Ran,Lin, Jin-Hong,Yu, Dong-Hai,Ma, Longle,Jia, Lina,Zhang, Lan,Wang, Lu,Xiao, Ji-Chang,Liang, Steven H.
, p. 3196 - 3200 (2017/03/17)
Trifluoromethylthiolation by sulfuration of difluorocarbene with elemental sulfur is described for the first time, which overrides long-standing trifluoromethyl anion-based theory. Mechanistic elucidation reveals an unprecedented chemical process for the
Kinetic and theoretical study on nucleofugality in the phenolysis of 3-nitrophenyl and 4-nitrophenyl 4-cyanophenyl thionocarbonates
Castro, Enrique A.,Ca?ete, Alvaro,Campodónico, Paola R.,Cepeda, Marjorie,Pavez, Paulina,Contreras, Renato,Santos, José G.
, p. 130 - 135 (2013/07/11)
The phenolysis of 3-nitrophenyl 4-cyanophenyl thionocarbonate (1) and 4-nitrophenyl 4-cyanophenyl thionocarbonate (2) are subjected to a kinetic investigation in order to evaluate the nucleofugality of the corresponding leaving groups. For the reaction of 2 only 4-nitrophenoxide is obtained as leaving group. For the reaction of 1 the nucleofugality ratio 3-nitrophenoxide/4-cyanophenoxide is 1/3 from the corresponding T- intermediate. Theoretical calculations confirm the experimental results. From these results it can be concluded that the non-leaving group affects the nucleofugality ratio.
