485-14-3Relevant academic research and scientific papers
FeCl3/SiO2 Reacts as Oxidant or Lewis Acid with Phenol Ethers
Jempty, Thomas C.,Gogins, Kitty A. Z.,Mazur, Yehuda,Miller, Larry L.
, p. 4545 - 4551 (1981)
Adsorption of FeCl3*6H2O onto silica gel produces a supported reagent FeCl3/SiO2.This reagent is insoluble in CH2Cl2 and is used in that solvent for reaction with phenol ethers.Dimethoxy aromatics are coupled to produce biaryls in high yield.Seven examples including both inter- and intramolecular couplings are reported.The effect of various support materials is explored.An electron-transfer mechanism is proposed.Disiloxy aromatics are oxidized to quinones.Ten examples of substituted 1,4-bis(trimethylsiloxy)- or 1,4-bis(tert-butyldimethylsilyloxy)benzene oxidations are reported.In one example the reaction is catalytic in FeCl3, being driven by oxygen.Benzyloxy aromatics are cleaved to phenols.In this reaction FeCl3 acts on a Lewis acid.The importance of coadsorbing the reagent and the aromatic ether in the absence of solvent is demonstrated.
The ethoxycarbonyl group as both activating and protective group in N-acyl-Pictet-Spengler reactions using methoxystyrenes. A short approach to racemic 1-benzyltetrahydroisoquinoline alkaloids
Bartel, Karin,Bracher, Franz,Geisslinger, Franz,Keller, Marco,Sauvageot-Witzku, Karl,Schaefer, Michael,Urban, Nicole
, p. 2716 - 2725 (2022/01/12)
We present a systematic investigation on an improved variant of the N-acyl-Pictet-Spengler condensation for the synthesis of 1-benzyltetrahydroisoquinolines, based on our recently published synthesis of N-methylcoclaurine, exemplified by the total syntheses of 10 alkaloids in racemic form. Major advantages are a) using ω-methoxystyrenes as convenient alternatives to arylacetaldehydes, and b) using the ethoxycarbonyl residue for both activating the arylethylamine precursors for the cyclization reaction, and, as a significant extension, also as protective group for phenolic residues. After ring closure, the ethoxycarbonyl-protected phenols are deprotected simultaneously with the further processing of the carbamate group, either following route A (lithium alanate reduction) to give N-methylated phenolic products, or following route B (treatment with excess methyllithium) to give the corresponding alkaloids with free N-H function. This dual use of the ethoxycarbonyl group shortens the synthetic routes to hydroxylated 1-benzyltetrahydroisoquinolines significantly. Not surprisingly, these ten alkaloids did not show noteworthy effects on TPC2 cation channels and the tumor cell line VCR-R CEM, and did not exhibit P-glycoprotein blocking activity. But due to their free phenolic groups they can serve as valuable intermediates for novel derivatives addressing all of these targets, based on previous evidence for structure-activity relationships in this chemotype.
Biotransformation of phenolic 1-benzyl-N-methyltetrahydroisoquinolines in plant cell cultures followed by LC/NMR, LC/MS, and LC/CD
Cui, Wenhua,Iwasa, Kinuko,Sugiura, Makiko,Takeuchi, Atsuko,Tode, Chisato,Nishiyama, Yumi,Moriyasu, Masataka,Tokuda, Harukuni,Takeda, Kazuyoshi
, p. 1771 - 1778 (2008/09/21)
(±)-1-Benzyl-N-methyltetrahydroisoquinolines 7-10 and 11-14 with one and two hydroxy groups on the aromatic rings, respectively, were fed individually to cultured cells of Corydalis and Macleaya species, respectively. The structures of the metabolites were determined by using combinatorial techniques, including LC/NMR, LC/MS-MS, and LC/CD. The enantiomeric excesses of the metabolites were derived from LC/CD and LC/MS-MS analyses. In cell cultures of Corydalis and Macleaya species, laudanine (7), with a hydroxy group at C-3′, can form the berberine bridge at C-2′ and C-6′ to produce S- and R-enantiomers of 2,3,9,10- and 2,3,10,11-oxygenated protoberberines (20 and 21), respectively, whereas reticuline (11) and protosinomenine (12), incoporating a hydroxy group at C-3′, form the berberine bridge at C-2′ to furnish the S-enantiomer of 2,3,9,10-oxygenated protoberberines (23 and 21), respectively.
