- Willgerodt-kindler's microwave-enhanced synthesis of thioamide derivatives
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The Willgerodt-Kindler reaction was applied to a series of aromatic aldehydes and ketones. The reactions were performed in a dipolar aprotic solvent (mainly DMF) in the presence of a base catalyst (4-methylmorpholine) and utilized microwave (mw) irradiation. The pulsed mw technique rather than the continuous irradiation was preferred because it limited side reactions and hydrogen sulfide production. While not always superior to the thermal activation of the reaction, the procedure involving repetitive short pulses of microwave irradiation was found to be faster and result in consistently cleaner products. The technique can be easily applied in a fast parallel synthesis process.
- Poupaert, Jacques H.,Duarte, Sandro,Colacino, Evelina,Depreux, Patrick,McCurdy, Christopher R.,Lambert, Didier L.
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p. 1959 - 1973
(2007/10/03)
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- Selective κ-opioid agonists: Synthesis and structure-activity relationships of piperidines incorporating an oxo-containing acyl group
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This study describes the synthesis and the structure-activity relationships (SARs) of the (S)-(-)-enantiomers of a novel class of 2- (aminomethyl)piperidine derivatives, using κ-opioid binding affinity and antinociceptive potency as the indices of biological activity. Compounds incorporating the 1-tetralon-6-ylacetyl residue (30 and 34-45) demonstrated an in vivo antinociceptive activity greater than predicted on the basis of their κ-binding affinities. In particular, (2S)-2-[(dimethylamino)methyl]- 1-[(5,6,7,8-tetrahydro-5-oxo-2-naphthyl)acetyl]piperidine (34) was found to have a potency similar to spiradoline in animal models of antinociception after subcutaneous administration, with ED50s of 0.47 and 0.73 μmol/kg in the mouse and in the rat abdominal constriction tests, respectively. Further in vivo studies in mice and/or rats revealed that compound 34, compared to other selective κ-agonists, has a reduced propensity to cause a number of κ-related side effects, including locomotor impairment/sedation and diuresis, at antinociceptive doses. For example, it has an ED50 of 26.5 μmol/kg sc in the rat rotarod model, exhibiting a ratio of locomotor impairment/sedation vs analgesia of 36. Possible reasons for this differential activity and its clinical consequence are discussed.
- Giardina,Clarke,Dondio,Petrone,Sbacchi,Vecchietti
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p. 3482 - 3491
(2007/10/02)
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