- Simple and efficient synthesis of racemic substituted mandelic acid esters from nonactivated arenes and ethyl glyoxylate
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Direct synthesis of racemic aromatic α-hydroxyacetic acid esters via Friedel-Crafts reaction of nonactivated, simple arenes with ethyl glyoxylate promoted by SnCl4 or AlCl3 is described. The use of SnCl4 opens a fast access to various alkyl- and aryl-substituted mandelic acids esters at room temperature within two hours in good yield (>80%) and with high regioselectivity. The procedure was successfully employed also for the alkylation of compounds with condensed aromatic rings. Alternative hydroxyalkylations with AlCl3 require longer reaction time and higher temperature to get a good yield.
- Kwiatkowski, Jacek,Majer, Jakub,Kwiatkowski, Piotr,Jurczak, Janusz
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experimental part
p. 3237 - 3244
(2009/05/26)
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- 1-Aryl-3-azabicyclohexanes, a New Series of Nonnarcotic Analgesic Agents
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A series of 1-aryl-3-azabicyclohexanes was synthesized by hydride reduction of 1-arylcyclopropanedicarboximides.Hydroxyphenyl analogues 20, 22, and 24 were prepared by EtSNa-DMF ether cleavage of the corresponding methoxyphenyl analogues 2m, 2n, and 23, respectively, with the secondary amines 20 and 22 going through the N-formyl intermediates 19 and 21.The p-ethoxy analogue 26 was obtained by O-ethylation of 19, followed by base hydrolysis of the amide 25.The greatest analgesic potency in mouse writhing and rat paw-pain assays was observed for para-substituted compounds.Bicifadine, 1-(4-methylphenyl)-3-azabicyclohexane (2b), was the most potent member of the series and is presently undergoing clinical trials in man.Analgesic activity of 2b is limited to the (+) enantiomer 2v, which has the 1R,5S absolute configuration as determined by single-crystal X-ray analysis.The N-methyl analogue (27d) of 2b showed significant analgesic potency, whereas the N-allyl (27a), N-(cyclopropylmethyl) (27b), and N-(n-hexyl) (27c) analogues were inactive.Bicifadine (2b) showed a nonnarcotic profile different from analogous azabicycloalkane and 3-phenylpyrrolidine analgesics.
- Epstein, Joseph W.,Brabander, Herbert J.,Fanshawe, William J.,Hofmann, Corris M.,McKenzie, Thomas C.,et al.
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p. 481 - 490
(2007/10/02)
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