The aryl substituents at positions 4 and 6 do not exert observable electronic effects on the ring-chain tautomeric ratios of 2,4- or 2,6-diarylsubstituted-tetrahydro-1,3-oxazines. On the other hand, the electronic effect of the 2-aryl substituent is marked: in all eight series studied, the equilibria can be described by the equation log K = ϱ σ+ +log K0, where ϱ+ is the Hammett-Brown constant of the
在4和6位上的芳基取代基对2,4-或2,6-二芳基取代的-四氢-1,3-恶嗪的环链互变异构比没有可观察到的电子效应。另一方面,2-芳基取代基的电子效应是明显的:在所有研究的八个系列中,平衡均可以用等式log K = ϱσ + + log K 0来描述,其中ϱ +是哈米特-布朗= 2-芳基取代基的常数,ϱ是环系统的恒定特征(= 0.75±0.05)。
[EN] NOVEL PROCESS FOR THE PREPARATION OF 4-ARYL-3-HYDROXYMETHYL-1-METHYLPIPERIDINES.<br/>[FR] NOUVEAU PROCEDE DE PREPARATION DE 4-ARYL-3-HYDROXYMETHYL-1-METHYLPIPERIDINES
申请人:NATCO PHARMA LTD
公开号:WO2004043921A1
公开(公告)日:2004-05-27
A novel, improved, and general process for the preparation of 4-aryl-3-hydroxymethyl-1-methylpiperidines is disclosed in the present invention. 4-(4-Fluorophenyl)-3-hydroxymethyl-1-methylpiperidine is a well-known intermediate in making the anti-depressant drug, paroxetine ((-)-trans-4-p-fluorophenyl-3-(3',4'-methylenedioxy-phenoxymethyl)piperidine). Novel N-methyl-N-[3-(4-substitutedphenyl (F, Me, OMe))-3-hydroxy]propylamines are prepared from the Mannich salts such as 3-dimethylamino- or 3-(N-methyl-N-benzylamino)-4'-substituted (F, Me, OMe) propiophenone hydrochlorides by conventional methods. The N-methyl-N-[3-(4-substitutedphenyl (H, F, Me, OMe))-3-hydroxy]propylamines thus obtained are reacted with ethyl or methyl acrylate to get the corresponding Michael addition products. The hydroxy group present in the Michael addition products is converted into a facile leaving group and treated with a strong base to get 4-aryl-N-methylpiperidine-3-carboxylates via the intramolecular cyclization in good yields. Reduction of the ester group present in these piperidine-3-carboxylates gave the title compounds as crystalline solids. Present process is easily adaptable for commercial preparation of the paroxetine intermediate (4-(4-fluorophenyl)-3-hydroxymethyl-1-methylpiperidine).
A highly enantioselective approach towards optically active γ-amino alcohols by tin-catalyzed kinetic resolution of 1,3-amino alcohols
作者:Jian Song、Wen-Hua Zheng
DOI:10.1039/d2cc01963a
日期:——
A highlyenantioselective kinetic resolution of racemic 1,3-amino alcohols via O-Acylation was achieved using a chiral organotin as the catalyst. Alkyl- and aryl-substituted 1,3-amino alcohols were resolved with excellent efficiencies to afford the recovered 1,3-amino alcohols and acylative products with high enantioselectivities, with s factors up to >600. Notably, the chiral organotin catalyst was
Regioselectively Functionalized Pyridines from Sustainable Resources
作者:Stefan Michlik、Rhett Kempe
DOI:10.1002/anie.201301919
日期:2013.6.10
Ir‐catalyzed dehydrogenative condensation of alcohols and 1,3‐amino alcohol was used to construct pyridine derivatives regioselectively. This method provides access to unsymmetrically substituted pyridines and tolerates a wide variety of functional groups. Three equivalents of H2 are generated per pyridine unit formed and the alcohol substrates become completely deoxygenated.