Esters of arylpropionic acids with 1,2:5,6-di-O-isopropylidene- and 1,2-O-isopropylidene-α-D-glucofuranose

Enzymatic resolution of methyl 2-alkyl-2-arylacetates

A novel polar dppf derivative possessing only planar chirality, 1′,2-bis(diphenylphosphino)-ferrocene-1-carboxylic acid (Hdpc), has been synthesised in racemic form and resolved into enantiomers via esters with D-glucose diacetonide ((Rp)- and (Sp)-3). (Rp)-Hdpc was further converted to a series of N-substituted amides that were studied as ligands for Pd-catalysed enantioselective allylic alkylation of racemic (E)-1,3-diphenylprop-2-en-1-yl acetate or ethyl carbonate with malonate esters, showing high activity and good enantioselectivity (er up to 10 : 90). The catalytic results were correlated with the structural data (X-ray diffraction and solution NMR) for (η3-allyl)palladium(II) complex (Rp)-[Pd(η3-1,3-Ph2C3H3){Fe(η5-C5H3-1-(C(O)NHCH2Ph)-2-(PPh2-κP))(η5-C5H4PPh2-κP)}]ClO4 (16) as a model of the plausible reaction intermediate. A further study into the coordination properties of Hdpc led to isolation of chelate complex [PdCl2(Hdpc-κ2P,P′)] (12). The crystal structures of rac-Hdpc, methyl ester of (Rp)-Hdpc, glycoside (Rp)-3, and 12·Me2CO suggested a close structural relationship between dppf and Hdpc.

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Preparation, coordination and catalytic use of planar-chiral monocarboxylated dppf analogues

Several esters of the nonsteroidal antiinflammatory drug Naproxen [2-(6-methoxy-2-naphthyl)propionic acid] were synthesized by standard procedures. Melting points and enthalpies of melting were obtained by differential scanning calorimetry. Solubilities in water were measured using HPLC. The partition coefficients (octanol/water) were calculated according to Rekker and Mannhold and Rm-values were determined by RP-TLC. The two latter parameters were correlated with high significance.

Ester des Naproxens als potentielle Prodrugs zur Hautpenetration, 1. Mitt.: Synthese und physikochemische Eigenschaften

Polarimetric detection in high-performance liquid chromatography (HPLC) might seem like a matter of course, especially in areas such as control of the optical purity of drugs or fingerprinting of herbal extracts. However, there are well founded reasons for the relatively low popularity of polarimetric detection in HPLC. Such reasons include, for example, the insufficient sensitivity of this type of detector when compared with photodiode array detection or evaporative light-scattering detection, or the economic factors. This paper, regarding an example of R(-)-naproxen, discusses physical phenomena (i.e., gelation of organic solvents by small organic molecules, the effect of molecular rotors and oscillatory interconversion of chiral analytes) that might obstruct the quantification of profen drugs (more generally, of chiral low molecular carboxylic acids) with the use of HPLC with polarimetric detection. The discussed (or analogous) phenomena are even more general, which hamper the widespread application of polarimetric detection in HPLC.

/pdf/polarimetric-detection-in-hplc-of-r-naproxen-features-and-tblsniycgy.pdf

Esters of arylpropionic acids with 1,2:5,6-di-O-isopropylidene- and 1,2-O-isopropylidene-α-D-glucofuranose

Citations

Enzymatic resolution of methyl 2-alkyl-2-arylacetates

Preparation, coordination and catalytic use of planar-chiral monocarboxylated dppf analogues

Ester des Naproxens als potentielle Prodrugs zur Hautpenetration, 1. Mitt.: Synthese und physikochemische Eigenschaften

Polarimetric Detection in HPLC of R(–)-Naproxen: Features and Intrinsic Weakness