5884-67-3Relevant articles and documents
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
supporting information, 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.
Synthesis of (+)-O-methylthalibrine by employing a stereocontrolled Bischler-Napieralski reaction and an electrochemically generated diaryl ether
Kawabata, Yuki,Naito, Yu,Saitoh, Tsuyoshi,Kawa, Kohei,Fuchigami, Toshio,Nishiyama, Shigeru
, p. 99 - 104 (2014/01/06)
An efficient electrochemical four-step route was developed for the preparation of diaryl ether derivatives by using halogenation and dehalogenation processes in addition to electrochemical phenolic oxidation and reduction reactions. The synthesis of (+)-O
Total synthesis of (±)-armepavines and (±)-nuciferines from (2-nitroethenyl)benzene derivatives
Chang, Chia-Fu,Huang, Chu-Yun,Huang, Yu-Chao,Lin, Kuan-Yu,Lee, Yean-Jang,Wang, Chau-Jong
experimental part, p. 3452 - 3466 (2011/02/22)
A concise route to armepavine 1 and nuciferine 2 and 3, which can be isolated from the leaves of Nelumbo nucifera (Nymphaceae), has been achieved in which the longest linear sequence is only six steps from commercially available benzaldehyde in 28%, 21%, and 20% overall yield, respectively. The key transformations in the synthesis are the radical cyclization of aryl bromide with Bu3SnH and the Pictet-Spengler reaction of N-substituted amine with aldehyde. Copyright Taylor & Francis Group, LLC.
