Asymmetric Synthesis of Arylpropionic Acids and Aryloxy Acids by Using Lactamides as Chiral Auxiliaries

Abstract

Two different dynamic kinetic resolution methods have been applied for the asymmetric synthesis of pharmaceutical arylpropionic acids and aryloxy acids by using amides of (S)-lactic acid as chiral auxiliaries. For arylpropionic acids the esterification mediated by dicyclohexylcarbodiimide (DCC) and 4-(dimethylamino)pyridine (DMAP) proceeds with good

Syntheses and cytotoxicity of phosphatidylcholines containing ibuprofen or naproxen moieties

“…Additionally, the structures of 9 and 10 were confirmed by the shift in the methine proton H-2 signals from δ = 3.92 ( 7 ) to δ = 5.19 ( 9 ) and from δ = 3.91 ( 8 ) to δ = 5.19 ( 10 ), respectively. Moreover, phosphatidylcholines 9 and 10 were obtained as mixtures of diastereomers, which was a result of the enolization of the carboester group with contribution of H-2′ from the ibuprofen or naproxen moiety under mildly alkaline conditions 29 . However, in acidic solutions, NSAIDs are reportedly highly stable and do not undergo racemization 30 .…”

Influence of benzylamine on the resolution of ibuprofen with (+)‐(R)‐phenylethylamine via supercritical fluid extraction

“…[9][10][11] Several new approaches adopting the use of ionic liquids also can be found in the literature. [12][13][14] Since the introduction of supercritical fluid extraction (SFE) as an alternative green technology for optical isomer separation, 15 numerous trials have been made in the search for different resolution systems.…”

Nonenzymatic Dynamic Kinetic Resolution of α‐(Arylthio)‐ and α‐(Alkylthio)alkanoic Acids

“…Methods based on the asymmetric generation of the stereogenic center in a-(arylthio)-and a-(alkylthio)alkanoic acids and their derivatives are restricted in their scope. [13] In the course of our recent studies [7c] on KR of asubstituted alkanoic acids catalyzed by homobenzotetramisole ((S)-HBTM, 7; Figure 1), [14a] we observed that the unreacted a-(phenylthio)propanoic acid was recovered with an unexpectedly low ee value when the reaction was carried out at room temperature (Scheme 3). Compared to classical resolution [4,5] and kinetic resolution (KR), [6,7] dynamic kinetic resolution (DKR), [8] which converts both enantiomers of the starting material into one enantiomer of the product, is especially attractive.…”

“…To the best of our knowledge, enantioselective, nonenzymatic DKR has so far been achieved for only two types of activated carboxylic acid derivatives: azlactones 1 [10] and cyclic carboxyanhydrides 2 [11,12] (Scheme 2). [13] In the course of our recent studies [7c] on KR of asubstituted alkanoic acids catalyzed by homobenzotetramisole ((S)-HBTM, 7; Figure 1), [14a] we observed that the unreacted a-(phenylthio)propanoic acid was recovered with an unexpectedly low ee value when the reaction was carried out at room temperature (Scheme 3). We realized that this result must be due to in situ racemization of the less-reactive enantiomer of the substrate.…”