Microbiological transformations—XII: Microbiological reduction of racemic 1-(2',2',3'-trimethyl-cyclopent-3'-en-1'-yl)propan-2-one and 1-(2',2',3'-trimethyl-cyclopent-3'-en-1'-yl)butan-2-one by rhodotorula mucilaginosa

The microbiological reduction of (±)-l-(2',2',3'-trimethylcyclopent-3'-en-l'-yl)-propan-2-one (4) and (±)-1-(2',2',3'-trimethylcyclopent-3'-en-l'-yl)-butan-2-one (5) by Rhodotorula mucilaginosa was investigated. Both enantiomers of 4 are reduced stereospecifically to corresponding alcohols; (+)-(2S, l'R)-(2',2',3'-trimethylcyclopent-3'-en-l'-yl)-propan-2-ol (6) and (-)-(2S,l'S)-(2',2',3'-trimethylcyclopent-3'-en-l'-yl)-propan-2-ol (7). p ]The substrate selectivity in the reduction of 5 was observed: R enantiomer of 5 yields stereospecifically (+)-(2S,1'R)-(2',2',3'-trimethylcyclopent-3'-en-l'-yl)-butan-2-ol (8) while S(-)5 remains unchanged.     

Isolation of the muricins : Evidence of a chemical adaptation against fouling in the marine octocoral Muricea fruticosa (gorgonacea)

Chemical comparisons of the closely-related Pacific gorgonians Muricea californica and M. fruticosa have shown that the much less fouled M. fruticosa contains four new esterified aminogalactose saponins assigned as the muricins-1 through -4 (1–4). The structures of these new saponins were defined by chemical degradation yielding the aglycone pregna-5,20-dien-3β-ol, and by extensive ¹H and ¹³C NMR investigations. Muricins-2, -3 and -4 were found to possess 2-acetamidogalactopyranose components with unprecedented n-butyrate ester functionalities in the C-4', C-6' and the C-4' and C-6' positions, respectively. At approximately natural concentrations, the muricins were found to inhibit growth of the marine diatom Phaeodactylum tricornutum. The muricins did not, however, possess the ichthyotoxic, cytotoxic, or antimicrobial effects reported for numerous marine-derived saponins. The potential role of these compounds in contributing to the reduced fouling of M. frulicosa is discussed.     

Biosynthesis of verrucarins and roridins. 3. Incorporation of 3R)-(5-14C)-and at C(2)stereospecific tritiated mevalonate into verrucarol]

Separate experiments, involving incorporation of either (3R)-[5-¹⁴C]-mevalonate or each enantiomer of [2-³H]-mevalonate into verrucartin A and roridin A, indicate that hydroxylation at C(4) of the tricothecane skeleton, to yield verrucarol (4), proceeds with an overall retention of configuration; they confirm that C(8) and not C(10) is derived specifically from C(2) or mevalonate.     

Triterpene glycosides of Thalictrum squarrosum. III. Structures of squarrogenins 1 and 2

Two genins — squarrogenin 1 and squarrogenin 2 — have been isolated from nodding meadow rue by the hydrolysis of squarrosides A1 and A2. The compounds are epimeric at C-21 and have the following structures: 1 — (21R, 22S, 23R)-21-methoxy-21,23-epoxycycloart-24-ene-3,22-30-triol, C₃₁H₅₀O₅, mp 169–171°C (hexane-acetone), [] ₅₄₆ ²⁰ –11.06° (c 4.52; pyridine); and 2 — (21S, 22S, 23R)-21-methoxy-21,23-epoxycycloart-24-ene-3,22,30-triol, C₃₁H₅₀O₅, mp 190–193°C (hexane-acetone), [] ₅₄₆ ²⁰ +106.6° (c 0.3; pyridine). The results of¹H and¹³C NMR spectroscopy and of mass spectrometry for the new compounds are given.Irkutsk Institute of Organic Chemistry, Siberian Division of the USSR Academy of Sciences. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 510–516, July–August, 1989.     

Structural study of tropane-3-spiro-4'-imidazol-5'-one

Tropane-3-spiro-4'-imidazol-5'-one has been synthesized and its crystal and molecular structures determined by X-ray diffraction, IR, Raman, ¹H-NMR and ¹³C-NMR methods. The tautomeric equilibrium between this structure and the corresponding conjugated form in different solvents is also studied from IR and UV data. The imidazoline ring, the spiranic C(3, 4'), the N(8) and the methyl C(9) atoms are situated in a plane. The piperidine ring adopts a distorted chair conformation in the crystalline form and in solution. The flattening of the C(1), C(2), C(3, 4'), C(4), C(5) part of the chair and the opposite puckering are noticeably large. In order to complete the results, some spectroscopic measurements have also been made for the tropane-3-spiro-4'-imidazol-5'-one hydrochloride.     

Carbon-13 NMR signals of some natural coumarins and their derivatives

The ¹³C NMR spectra of the natural coumarins ostruthin, osthol, aegelinol (enantiomer of decursinol), luvangetin, seselin, anomalin, oxypeucedanin (and its enantiomer prangolarin) and oxypeucedanin hydrate and some of their derivatives have been studied. Self-consistent resonance assignments have been made following chemical shift theory and using simple models. Carbon-hydrogen coupling constants of some compounds are also reported. The alkoxy group/s at C-5 and/or C-8 in linear furocoumarins, as well as in linear pyranocoumarins, have unusually small shielding effects on the ortho- and para-carbons. This study also indicates that the C-4a and C-8 resonance assignments of osthol, made earlier, should be reversed.     

A Validated LC Method for Separation and Quantification of Voriconazole and Its Enantiomer

A simple liquid chromatographic method was developed for the separation and quantification of voriconazole and its enantiomer in drug substance. The separation was achieved on Chiral cel-OD (250 mm × 4.6 mm × 10 μm) using mobile phase consisting of n-hexane and ethanol in the ratio 9:1 (v/v) with a flow rate of 1.0 mL min⁻¹, at 27 °C column temperature and detection at 254 nm with an injection volume of 20 μL. Ethanol was used as diluent. The method is capable of detecting the (2S, 3R) enantiomer down to 0.0075% and can quantify down to 0.021% with respect to sample concentration. The method is rapid and the resolution achieved was about 3.0. This method can be employed for the quantification of (2S, 3R) enantiomer in voriconazole drug substance.     

5'-Substituted 2,2'-anhydrouridines

3',5'-Di-O-acetyl-2'-halogenouridines (1a, 1c and 1d) can be partially deacetylated at C-5' by transesterification with methanol-HCl, providing the 3'-O-acetyl derivatives 2a–2c. These can be converted into the 5'-O-mesyl derivatives 3a–3c, and latter into the 5'-chloro compounds 3d-3f. All 5'-substituted 2'-halogeno compounds give the corresponding 2,2'-anhydrouridine derivatives 4a–4c on treatment with NaOMe. Structures were proved by IR and ¹H-NMR.     

Study on the CID Fragmentation Pathways of Deprotonated 4’-Monophosphoryl Lipid A

Lipid A, the membrane-bound phosphoglycolipid component of bacteria, is held responsible for the clinical syndrome of gram-negative sepsis. In this study, the fragmentation behavior of a set of synthetic lipid A derivatives was studied by electrospray ionization multistage mass spectrometry (ESI-MSⁿ), in conjunction with tandem mass spectrometry (MS/MS), using low-energy collision-induced dissociation (CID). Genealogical insight about the fragmentation pathways of the deprotonated 4’-monophosphoryl lipid A structural analogs led to proposals of a number of alternative dissociation routes that have not been reported previously. Each of the fragment ions was interpreted using various possible mechanisms, consistent with the principles of reactions described in organic chemistry. Specifically, the hypothesized mechanisms are: (i) cleavage of the C-3 primary fatty acid leaves behind an epoxide group attached to the reducing sugar; (ii) cleavage of the C-3’ primary fatty acid (as an acid) generates a cyclic phosphate connected to the nonreducing sugar; (iii) cleavage of the C-2’ secondary fatty acid occurs both in acid and ketene forms; iv) the C-2 and C-2’ primary fatty acids are eliminated as an amide and ketene, respectively; (v) the ^0,2A₂ cross-ring fragment contains a four-membered ring (oxetanose); (vi) the ^0,4A₂ ion is consecutively formed from the ^0,2A₂ ion by retro-aldol, retro-cycloaddition, and transesterification; and (vii) formations of H₂PO₄⁻ and PO₃⁻ are associated with the formation of sugar epoxide. An understanding of the relation between ^0,2A₂ and ^0,4A₂-type sugar fragments and the different cleavage mechanisms of the two ester-linked primary fatty acids is invaluable for distinguishing lipid A isomers with different locations of a single ester-linked fatty acid (i.e., at C-3 or C-3’). Thus, in addition to a better comprehension of lipid A fragmentation processes in mass spectrometers, our observations can be applied for a more precise elucidation of naturally occurring lipid A structures.     

Insect pheromones and their analogs

A four-stage asymmetric synthesis of (+)-disparlure [(7R,8S)-(+)-cis-methyl-7,8-epoxyoctadecane (V)] has been effected from 8-methylnon-2Z-en-l-ol (I), obtained by the carboalumination of acetylene with tris(5-methylhexyl)aluminum using the Sharpless reaction. The asymmetric epoxidation of (I), (Ar, mol. sieve A, (+)-DET, (iOPr)₄Ti, t-BuOOH, –15°C, 20 h; H₂O, 1 h, NaOH, –7°C, 30 min) gave 8-methyl-2S,3R-epoxynonan-l-ol (II), which was oxidized (kieselguhr-CrO₃-Py, 0°C, 2 h; 25°C, 2 h) to 8-methyl-2S,3R-epoxynonan-l-al (III). The coupling of (III) with n-C₈H₁₇CH=PPh₃ (–78°C, 1 h; 25°C, 15 h) gave 2-methyl-7R,8S-epoxyoctadec-9Z-ene (IV), the hydrogenation (H₂/5% Pd-C, 25°C, 5 days) of which led to (V) in admixture with an isomerization product. Compound (V) was isolated by HPLC. Substance, yield, [] _D ²⁵ : (II), 73, –2.75°; (III), 80, [80.8°; (IV), 50, +37.25°; (V), 50, +0.8°. The IR and PMR spectra of (II–IV), the¹³C NMR spectra of (II) and (III), and the mass spectrum of (IV) are given.Institute of Chemistry, Bashkir Scientific Center, Urals Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 715–718, September–October, 1989.     

Conformational Behaviour of Substituted 2-Methoxy-2-Oxo-1,2-Oxaphospholan-3-Ols

Abstract

Conformational behaviour of about 30 2-methoxy-2-oxo-1,2- oxaphospho l an-3-0 1 s containing various substituents was examined by ¹H and ¹³C NMR. Vicinal coupling constants J(HCCH), J(HCCP), J(HCOP), J(CCOP) and J(CCCP) were employed in this study. Conformation of the 1,2-oxaphospholane ring is governed almost exclusively by substituents at C-3, C-4 and C-5, as we l l as by their orientation. The configuration of the P atom has little or no influence on conformation of the ring in diastsreomeric pairs. Strong preference of phenyl, methyl and substituted methyl groups to occupy the equatorial or pseudoequatoria l positions was observed for all but one compounds studied. In the cis-fused bicyclic syst ems conformat ionally rigid 6-membered rings forced the 1,2-oxaphospholane rings to adopt an enve l ope-l ike (E₄) conformation. No influence of the p=o……HO-C-3 hydrogen bond on conformation of the 1,2-oxaphospholane ring was found. Preferred conformations for (2R, 3R, 4R)-3-(hydroxymethyI)-2-methoxy-2-oxo-1,2-oxaphospho lane-3,4-diol and its triacetate are shown below.     

New aryl ethynylene substituted silicon-centered molecules

The reactions of substituted dichlorosilane monomers,Cl₂SiRR′, with two equivalents of lithium aryl acetylide(1), LiC ≡ C-4-C₆H₄-Ph, afford RR′Si(C ≡ C-4-C₆H₄-Ph)₂ (6: R,R′ =CH₃; 7: R = CH₃, R′ = CH=CH₂; 8: R,R′ = Ph). An isomeric mixture of meso, (R,R)- and (S,S)-Bis[2-(N,N-dimethylaminomethyl)ferrocenyl]dichlorosilane (5) was used as starting chlorosilyl compound for reaction with LiC ≡ C-4-C₆H₄-Ph to give (FcN)₂Si(C ≡ C-4-C₆H₄-Ph)₂ (9). A detailedcharacterization of 6, 7, 8 and 9 has been carried out by ¹H-NMR, ¹³C-NMR, ²⁹Si-NMR, IR and UV-VIS spectroscopy. The crystal structure of 9 has been determined by X-ray diffraction analysis.     

Configurationally and conformationally homogeneous cyclic n-aryl sulfimides—IV : Synthesis,configuration and stereochemistry of the rearrangement of 1,3-di-thiane-1-N-p-chlorophenylimides

1,3-Dithiane-1-N-p-chlorophenylimides (1,4-9) were prepared and their configuration and conformation was determined by ¹H and ¹³C NMR. The compounds were rearranged to the corresponding 2-(2'-amino-5'-chlorophenyl)-1, 3-dithianes (1U,4U,9U). The rearrangement reactions took place with ?95% stereospecifity. The mechanism of the reaction was investigated with the aid of analogs specifically deuterated at C-2.     

Dihydroisocoumarins and Dihydroisoflavones from the Rhizomes of Dioscorea collettii with Cytotoxic Activity and Structural Revision of 2,2′-Oxybis(1,4-di-tert-butylbenzene)

The investigation of the constituents of the rhizomes of Dioscorea collettii afforded one new dihydroisocoumarin, named (−)-montroumarin (1a), along with five known compounds—montroumarin (1b), 1,1′-oxybis(2,4-di-tert-butylbenzene) (2), (3R)-3′-O-methylviolanone (3a), (3S)-3′-O-methylviolanone (3b), and (RS)-sativanone (4). Their structures were elucidated using extensive spectroscopic methods. To the best of our knowledge, compound 1a is a new enantiomer of compound 1b. The NMR data of compound 2 had been reported but its structure was erroneous. The structure of compound 2 was revised on the basis of a reinterpretation of its NMR data (1D and 2D) and the assignment of the ¹H and ¹³C NMR data was given rightly for the first time. Compounds 3a–4, three dihydroisoflavones, were reported from the Dioscoreaceae family for the first time. The cytotoxic activities of all the compounds were tested against the NCI-H460 cell line. Two dihydroisocoumarins, compounds 1a and 1b, displayed moderate cytotoxic activities, while the other compounds showed no cytotoxicity.     

Antibiofilm and Anti-Quorum Sensing Potential of Cycloartane-Type Triterpene Acids from Cameroonian Grassland Propolis: Phenolic Profile and Antioxidant Activity of Crude Extract

Propolis is very popular for its beneficial health properties, such as antimicrobial activity and antioxidant effects. It is one of the most long-serving traditional medicines to mankind due to its interesting chemical diversity and therapeutic properties. The detailed chemical information of propolis samples is very necessary to guarantee its safety and for it to be accepted into health care systems. The phenolic profile of the hydroethanolic extract was determined using HPLC-DAD, and the antioxidant was evaluated using five complementary methods. Triterpenoids were isolated using column chromatography and characterized using ¹H NMR and ¹³C NMR. The effects of the extract and the isolated compounds on quorum sensing mediated processes and biofilm formation in bacteria were evaluated. Protocatechic acid (40.76 ± 0.82 µg/g), 4-hydroxybenzoic acid (24.04 ± 0.21 µg/g), vanillic acid (29.90 ± 1.05 µg/g), quercetin (43.53 ± 1.10 µg/g), and luteolin (4.44 ± 0.48 µg/g) were identified and quantified. The extract showed good antioxidant activity in the DPPH^•, ABTS^•+, CUPRAC, and metal chelating assays, and this antioxidant effect was confirmed by cyclic voltammetry. 27-Hydroxymangiferonic acid (1), Ambolic acid (2), and Mangiferonic acid (3) were isolated from anti-quorum sensing activity at MIC, and it was indicated that the most active sample was the extract with inhibition diameter zone of 18.0 ± 1.0 mm, while compounds 1, 2, and 3 had inhibition zones of 12.0 ± 0.5 mm, 9.0 ± 1.0 mm, and 12.3 ± 1.0 mm, respectively. The samples inhibited the P. aeruginosa PA01 swarming motility at the three tested concentrations (50, 75, and 100 μg/mL) in a dose-dependent manner. The propolis extract was able to inhibit biofilm formation by S. aureus, E. coli, P. aeruginosa, C. albicans, and C. tropicalis at MIC concentration. Compound 1 proved biofilm inhibition on S. aureus, L. monocytogenes, E. faecalis, E. coli, and C. tropicalis at MIC and MIC/2; compound 2 inhibited the formation of biofilm at MIC on S. aureus, E. faecalis, E. coli, S. typhi, C. albicans, and C. tropicalis; and compound 3 inhibited biofilm formation on E. faecalis, E. coli, C. albicans, and C. tropicalis and further biofilm inhibition on E. coli at MIC/4 and MIC/8. The studied propolis sample showed important amounts of cycloartane-type triterpene acids, and this indicates that there can be significant intra-regional variation probably due to specific flora within the vicinity. The results indicate that propolis and its compounds can reduce virulence factors of pathogenic bacteria.     

A study of the binding of manganese (II) with the sodium salts of nucleosides in aqueous solutions by the13C NMR method

The binding of manganese(II) with nucleosides — adenosine (A), guanosine (G), cytidine (C), and uridine (U) — in an alkaline D₂O solution has been investigated by the¹³C NMR method. It has been established that the structure of the paramagnetic Mn(II)—nucleoside complexes differs substantially in neutral and in alkaline media. The broadening of the resonance lines (C-2, C-3 > C-1, C-4 > C-5) shows the localization of the Mn(II) in the C-2 and C-3 hydroxyls of the ribose in an alkaline medium. It has been shown for the case of U that the degree of complex-formation depends on the pH of the solution. It is assumed that the nucleoside forms intramolecular complexes (I) with Mn(OH)₂.All-Union Scientific-Research Institute of Applied Biochemistry, Olaine. Institute of Organic Synthesis, Academy of Sciences of the Latvian SSR, Riga. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 565–570, July–August, 1979.     

NMR studies of 4(3H)-quinazolinones and 4(3H)-quinazolinethiones

Summary Unambiguous¹H and¹³C NMR assignments for 4(3H)-quinazolinones1–6 and their corresponding 4-thiones7–12 have been made. This resulted in the revision of the previous assignments for the two benzenoid carbons (C-5 and C-8) of quinazolinones1,2,4, and5. Thionation of the nucleophilic amides1–6 has been found to cause a distinct change in the¹³C chemical shift of particularly C-4, but also of those of C-4a, C-5, and C-8a. One-bond and several long range heteronuclear coupling constants for the compounds have also been measured.

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Kernresonanzspektroskopie von 4(3H)-Chinazolinonen und 4(3H)-Chinazolinthionen

Zusammenfassung Die¹H- und¹³C-NMR-Spektren der 4(3H)-Chinazolinone1–6 und ihrer entsprechenden 4-Thione7–12 wurden zugeordnet. Dabei zeigte sich, daß eine frühere Zuordnung der beiden benzoiden Kohlenstoffe (C-5 und C-8) der Chinazolinone1,2,4 und5 falsch war. Ersatz des Sauerstoffs durch Schwefel in den nukleophilen Amiden1–6 führt insbesondere für C-4, aber auch für C-4a, C-5 und C-8a zu einer deutlichen Änderung der chemischen Verschiebung. Heteronukleare Kopplungskonstanten über eine und über mehrere Bindungen wurden bestimmt.

     

An investigation of mononuclear and binuclear palladium(II) complexes of egta (egta = glycine,N,N′-(1,2-ethanediylbis(oxy-2,1-ethanediyl)bis[N-carboxymethyl]) by 1H-, 13C- and 15N-n.m.r. methods

1:1 and 2:1 palladium(II) complexes of egta^4– (egta^4– = glycine, N,N-(1,2-ethanediylbis)(oxy-2,1-ethanediyl)bis[N-carboxymethyl]) were prepared by 1:1 and 2:1 addition of K₂PdCl₄ to K₄egta, and examined by ¹H-, ¹³C- and ¹⁵N-n.m.r. methods. The 1:1 complex, [Pd(egta)]^2– in solution, utilizes a square-planar coordination comprised of two nitrogen and two glycinato carboxylate donors of egta^4–, leaving two glycinato carboxylates pendant. The complex has a cis-(R,S) stereochemistry which places both pendant carboxylates below the PdN₂O₂ square plane and the tether backbone of egta^4– in the up, up sense above the same plane. The cis-(R,S) assignment was assisted by computer simulations of the ¹³C-n.m.r. spectrum for four possible isomers. Only cis-(R,S) and trans-(R,R) calculated ¹³C-spectra were compatible with the observed ¹³C-n.m.r. pattern. The HH NOESY spectrum of [Pd(egta)]^2– detects long range coupling of the backbone –OCH₂CH₂O– linkage with both coordinated and pendant glycinato CH₂ moieties. The cis-(R,S) isomer's tortional movements allow such contacts whereas a trans-(R,R) isomer does not. The 2:1 complex, [Pd₂(egta)(H₂O)₂] in solution has an extended-chain structure with each palladium(II) center coordinated in the mer-iminodiacetate-like coordination with two bound glycinato-functionalities.     

Metallacycle Expansion <Emphasis Type="Italic">via</Emphasis> butadiyne/octadiyne Insertion into a Four-membered Ruthenium Organometallic

The reaction of 1,4-diphenylbutadiyne and 1,7-octadiyne with Ru(RL¹)(PPh₃)₂(CO)Cl (1) has respectively generated the inserted product [Ru(RL²XY)(PPh₃)₂(CO)Cl] (X=Ph, Y=-C≡C-Ph), (2) and [Ru(RL²Z)- (PPh₃)₂(CO)Cl]₂(CH₂)₄ (Z=H), (3) in excellent yield (RL¹ is C₆H₂O-2-CHNHC₆H₄R(p)-3-Me-5, RL² is C₆H₂(C=C-1)-O-2-CHNHC₆H₄R(p)-3-Me-5 and R is Me, OMe or Cl). In the conversions (1) (2)/(3) the Ru(C,O) chelate ring expands from four-membered to six-membered, and the structure determination of [2(Cl) · H₂O] authenticates the insertion process. The (σ-styryl)phenolato chelate ring, along with the benzene ring and the aldimine function (C₆H₄Cl and Me excluded), constitutes a good plane (mean deviation, 0.06 Å). The aryl rings at C9 and N1 make dihedral angles of 77° and 27° respectively with the above plane. Characteristic spectral data (u.v.–vis, i.r. and ¹H-n.m.r.) of the complexes are reported. A notable feature is that an allowed band appears near 620 nm due to the t (azomethine) charge transfer transition which is diagnostic of the coordinated iminium-phenolato function present in (2) and (3). In ¹H-n.m.r. the N⁺–H signals in (2) and (3) (near 12.5 ppm) are split into a doublet due to trans coupling with the azomethine proton. The C=N stretching frequency is relatively high (near 1630 cm⁻¹) and this is consistent with the protonation of nitrogen. In CH₂Cl₂ solution (2) and (3) display one and two quasireversible Ru^III/Ru^II cyclic voltammetric responses with E_1/2 near 0.4 V and 0.4 V, 0.7 V versus s.c.e. due to the presence of one and two Ru^II centers, respectively. The conversions (1)(2)/(3) are accompanied by the cleavage of the Ru-O bond by MeOH. Then alkyne π-anchoring and activation is believed to occur via displacement of MeOH. Subsequent (2+2) addition between Ru-C and C=C(alkyne), and regeneration of the Ru-O(phenolato) bond, completes the two carbon metallacycle expansions, furnishing (2) and (3).     

A Validated Chiral HPLC Method for the Determination of Enantiomeric Purity of R-β-amino-β-(4-methoxyphenyl) Propionic Acid

A normal phase chiral LC method for chiral purity evaluation of β-amino-β-(4-methoxyphenyl) propionic acid was developed on donor–acceptor (pirkle) column. The chiral stationary phase used was a 250 × 4.6 mm (R, R) Whelk-01 with 5 μm particle size, which was accompanied with a 1 cm long guard column. The “hybrid” pi-electron donor–acceptor based stationary phase (R, R) Whelk-01 was found to be enantiomeric selective for (R) and (S) enantiomers of β-amino-β-(4-methoxyphenyl) propionic acid with a resolution >2.5. The concentration of 2-propanol and TFA in the mobile phase plays an important role on the chrmatographic efficiency and resolution between the enantiomers. The limit of detection and limit of quantification of (S) enantiomer was 0.3 and 1.0 μg mL^-1 for 20 μL injection volume. The percentage RSD of the peak area of six replicate injections of (S) enantiomer at LOQ concentration was 4.5. The percentage recovery of (S) enantiomer from (R) enantiomer samples ranged from 92 to 100. The test solution was observed to be stable up to 24 h after the preparation. The developed method was also checked by different analysts and on different lots of columns, reagents and it was proved to be rugged. The developed normal phase chiral LC method can be used for the determination of the enantiomeric purity of R-β-amino-β-(4-methoxyphenyl) propionic acid.