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Showing papers on "Carboxylic acid published in 1996"


Journal ArticleDOI
TL;DR: In this paper, a synthesis of low molecular weight carboxylic acids in tropospheric aqueous and gaseous phases and in aerosol particles for different environments is presented.

696 citations


Journal ArticleDOI
TL;DR: The reactivity and packing density of the MUA-NHSS esters are investigated in detail by reacting these intermediates with ammonia (NH3), and nearly all of theMUA molecules (∼80%) are converted to amides.
Abstract: A monolayer of poly(l-lysine) (PL) is attached covalently via amide bonds to an alkanethiol self-assembled monolayer (SAM) on a gold surface. The amide bond is formed in two steps: the terminal carboxylic acid groups of an 11-mercaptoundecanoic acid (MUA) SAM are first activated to the N-hydroxysulfosuccinimide (NHSS) ester, followed by reaction of this MUA-NHSS ester monolayer with the amino groups of PL to create multiple amide bond linkages to the surface. The reactivity and packing density of the MUA-NHSS esters are investigated in detail by reacting these intermediates with ammonia (NH3). In the NH3 experiments, approximately 50% of the carboxylic acids in the MUA monolayer are converted to amides during the first cycle of this two-step surface reaction. This reaction yield of 50% is limited by the steric packing of the NHSS ester intermediate. However, after three cycles of MUA activation to the NHSS ester and reaction with NH3, nearly all of the MUA molecules (∼80%) are converted to amides. Polari...

308 citations


Patent
25 Jan 1996
TL;DR: In this article, a method for manufacturing cobalt complexes having the formula: [Co(NH3)5M]Ty, wherein M ligands are selected from substituted and unsubstituted C1-C30 carboxylic acids having the formulas: RC(O)O-
Abstract: A method for manufacturing cobalt complexes having the formula: [Co(NH3)5M]Ty, wherein M ligands are selected from substituted and unsubstituted C1-C30 carboxylic acids having the formulas: RC(O)O-; said method comprising reacting cobalt (II) complexes having the formula [Co(H2O)6] Ty (e.g., T is chloride) with concentrated ammonium hydroxide/ammonium chloride, followed by an oxidizing agent (e.g., peroxide), followed by carboxylic acid anhydride of the formula RC(O)O(O)CR.

274 citations


Journal ArticleDOI
TL;DR: In this paper, surface-catalyzed CrVI reduction has been demonstrated with α-hydroxyl carboxylic acids (glycolic acid, lactic acid, mandelic acid and tartaric acid) and their esters (methyl glycolate, methyl lactate, and methyl mandelate).
Abstract: CrVI reduction by low molecular weight organic compounds with various functional groups was examined in the presence and absence of oxide surfaces. Surface-catalyzed CrVI reduction has been demonstrated with α-hydroxyl carboxylic acids (glycolic acid, lactic acid, mandelic acid, and tartaric acid) and their esters (methyl glycolate, methyl lactate, and methyl mandelate), with α-carbonyl carboxylic acids (glyoxylic acid and pyruvic acid), with oxalic acid, and with substituted phenols (salicylic acid, 4-methoxyphenol, and resorcinol). Both goethite (α-FeOOH) and aluminum oxide (γ-Al2O3) exert an appreciable catalytic effect, although somewhat less than that observed with titanium dioxide. This study indicates that surface-catalyzed CrVI reduction may occur in soils, sediments, aquifers, and other aquatic environments rich in mineral surfaces.

272 citations


Journal ArticleDOI
TL;DR: In this article, the synthesis of β-cyclodextrin derivatives with carboxylic acid functionality of phenylalanine and the side chain thiol group of cysteine is described.
Abstract: The syntheses of the heptaamino acid-substituted β-cyclodextrins per-6-[(phenylalanyl)amino]-β-cyclodextrin (6), per-6-cysteinyl-β-cyclodextrin (7), as well as the per-2,3-dimethyl-per-6-cysteinyl-β-cyclodextrin (12) are described. The amino acids were coupled to the primary face of the β-cyclodextrin torus using the backbone carboxylic acid functionality of phenylalanine and the side chain thiol group of cysteine. In the case of the heptacysteinyl derivatives, polyzwitterionic compounds were obtained and shown to be highly water soluble.

255 citations


Journal ArticleDOI
TL;DR: The methanol extract from the whole plant of Geum japonicum was found to inhibit the human immunodeficiency virus (HIV-1) protease through bioassay-directed fractionation of the extract, and a new triterpene acid showed potent inhibitory activity against HIV-1 protease.
Abstract: The methanol extract from the whole plant of Geum japonicum was found to inhibit the human immunodeficiency virus (HIV-1) protease. Through bioassay-directed fractionation of the extract, a new triterpene acid along with five known triterpene acids, ursolic acid, epipomolic acid, maslinic acid, euscaphic acid, and tormentic acid, were isolated. The structure of the new compound was determined by spectral means including 1H-1H COSY, HMQC, HMBC, and NOE experiments to be 2 alpha, 19 alpha-dihydroxy-3-oxo-12-ursen-28-oic acid (1). Of these compounds, 1, ursolic acid, and maslinic acid showed potent inhibitory activity against HIV-1 protease.

219 citations


Journal ArticleDOI
TL;DR: The crystal structure of the xanthine oxidase-related molybdenum-iron protein aldehyde oxido-reductase from the sulfate reducing anaerobic Gram-negative bacterium Desulfovibrio gigas (Mop) was analyzed in its desulfo-, sulfo-, oxidized, reduced, and alcohol-bound forms at 1.8-A resolution as mentioned in this paper.
Abstract: The crystal structure of the xanthine oxidase-related molybdenum-iron protein aldehyde oxido-reductase from the sulfate reducing anaerobic Gram-negative bacterium Desulfovibrio gigas (Mop) was analyzed in its desulfo-, sulfo-, oxidized, reduced, and alcohol-bound forms at 1.8-A resolution. In the sulfo-form the molybdenum molybdopterin cytosine dinucleotide cofactor has a dithiolene-bound fac-[Mo, = O, = S, ---(OH2)] substructure. Bound inhibitory isopropanol in the inner compartment of the substrate binding tunnel is a model for the Michaelis complex of the reaction with aldehydes (H-C = O,-R). The reaction is proposed to proceed by transfer of the molybdenum-bound water molecule as OH- after proton transfer to Glu-869 to the carbonyl carbon of the substrate in concert with hydride transfer to the sulfido group to generate [MoIV, = O, -SH, ---(O-C = O, -R)). Dissociation of the carboxylic acid product may be facilitated by transient binding of Glu-869 to the molybdenum. The metal-bound water is replenished from a chain of internal water molecules. A second alcohol binding site in the spacious outer compartment may cause the strong substrate inhibition observed. This compartment is the putative binding site of large inhibitors of xanthine oxidase.

212 citations


Journal ArticleDOI
TL;DR: In this article, Fourier transform infrared spectroscopy was used to identify five-membered cyclic an hydride intermediates formed under the curing conditions of polycarboxylic acids.
Abstract: Multifunctional polycarboxylic acids have been used as nonformaldehyde cross linking agents for cotton fabrics to replace the traditional N-methylol reagents. Ester ification of cotton cellulose by seventeen aliphatic and aromatic polycarboxylic acids is studied using Fourier transform infrared spectroscopy. Five-membered cyclic an hydride intermediates formed under the curing conditions are identified on cotton fabrics treated with these acids. Only those polycarboxylic acids that form cyclic an hydride intermediates esterify cotton cellulose. Formation of the cyclic anhydride intermediates and esterification of cotton cellulose take place in the same curing tem perature regions. The infrared spectroscopy data also indicate that the second carboxyl group in a bifunctional carboxylic acid is not able to esterify cotton cellulose effectively. Therefore, we can conclude that a polycarboxylic acid esterifies cotton cellulose through the formation of a cyclic anhydride intermediate. The infrared spectroscopy ...

181 citations


Journal ArticleDOI
TL;DR: In this article, cellulose esters with linear aliphatic acyl substituents ranging in size from C12 (lauric acid) to Eicosanoic acid were prepared in homogeneous solution (DMAc/LiCl) using a novel synthetic method based on the use of a mixed p-toluenesulfonic/carboxylic acid anhydride.
Abstract: Cellulose esters with linear aliphatic acyl substituents ranging in size from C12 (lauric acid) to C20 (eicosanoic acid) were prepared in homogeneous solution (DMAc/LiCl) using a novel synthetic method based on the use of a mixed p-toluenesulfonic/carboxylic acid anhydride. The resulting waxy cellulose esters had a high degree of substitution (DS), between 2.8 and 2.9, and showed little degradation. Thermal analysis of these cellulose derivatives by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) revealed a series of transitions that represented motion by both ester substituents and cellulosic main chain. Broad crystallization and melting transitions attributed to side-chain crystallinity were observed in the range between −19 and +55°C; these side-chain Tm and Tc transition temperatures increased by 10°C per carbon atom of the ester substituent. The Tg of these derivatives increased linearly with increasing substituent size from 94°C for C12 (cellulose laurate) to 134°C for C20 (cellulose eicosanoate). Evidence of “main-chain” crystallization was not observed for these samples, except in the case of peracetylated C12 and C14 esters, which had Tm values of 96°C and 107°C, respectively. © 1996 John Wiley & Sons, Inc.

171 citations


Journal ArticleDOI
TL;DR: Heparin was almost not released from the immobilized surfaces in the physiological solution for 100 h, indicating good stability of immobilized heparin, showing increased hydrophilicity of the modified surfaces.

168 citations


Journal ArticleDOI
TL;DR: In this paper, a complete kinetic equation for describing the reaction catalyzed by Amberlyst 15 was developed, which can be used in the simulation and design of the catalytic distillation column for removing acetic acid from wastewater.
Abstract: Computer simulation showed that catalytic distillation is an attractive process for the removal of dilute acetic acid from wastewater. Selection of catalysts and kinetic data have been obtained for the design of the catalytic distillation column. Kinetic measurements were conducted in a batch reactor. Methanol was added to the dilute acetic acid solutions and reacted with the acid in water to form methyl acetate and water. The reaction can be catalyzed by solid acid catalysts. It was found that Amberlyst 15 was an effective catalyst for this reaction. The effects of stirrer speed, reaction temperature, reactant concentration and catalyst loading on reaction rate were investigated. A complete kinetic equation for describing the reaction catalyzed by Amberlyst 15 was developed. This equation can be used in the simulation and design of the catalytic distillation column for removing acetic acid from wastewater.

Journal ArticleDOI
TL;DR: In this article, rain and snow samples collected at nine southern California sites and time series rain samples obtained during 13 rain events were studied for their content of polar organic compounds, including C1-C9 monocar-ylic acids, C2-C10 α, ω-dicar-nodes, C1−C2 aldehydes and C2−C3 α-diciarbonyls.

01 Jan 1996
TL;DR: In this paper, the reaction of semicrystalline poly(ethylene terephthalate) (PET) film with ester-selective reagents at the film−solution interface can be controlled to produce modified film samples containing a thin (less than ∼ 40 A) surface layer of the reagent-induced functionality.
Abstract: Reactions of semicrystalline poly(ethylene terephthalate) (PET) film with ester-selective reagents at the film−solution interface can be controlled to produce modified film samples containing a thin (less than ∼ 40 A) surface layer of the reagent-induced functionality. Hydrolysis of PET yields a surface mixture of alcohol and carboxylic acid groups. Reduction with lithium aluminum hydride and transesterification with ethylene glycol (glycolysis) both produce surfaces with alcohol functionality (PET−OHR and PET−OHG, respectively). Each of these modification reactions involves chain cleavage and can lead to significant sample degradation (reactive dissolution); for each modification reaction, conditions were optimized to maximize conversion and minimize degradation. The reactivity of surface alcohols (PET−OH) was assessed for samples prepared by both reduction and glycolysis, and a comparative analysis was made: the presence of benzylic alcohols in reduced samples and their absence in glycolyzed samples as...

Patent
02 Feb 1996
TL;DR: An additive composition comprising an ashless dispersant comprising an acylated nitrogen compound; and a carboxylic acid, or an ester of the carboxyl acid and an alcohol wherein the acid has from 2 to 50 carbon atoms and the alcohol has one or more carbon atoms provides an improvement in the lubricity of fuel oils and exhibits improved solubility in the fuel oil.
Abstract: An additive composition comprising: (a) an ashless dispersant comprising an acylated nitrogen compound; and (b) a carboxylic acid, or an ester of the carboxylic acid and an alcohol wherein the acid has from 2 to 50 carbon atoms and the alcohol has one or more carbon atoms provides an improvement in the lubricity of fuel oils and exhibits improved solubility in the fuel oil.

Journal ArticleDOI
07 Feb 1996-Langmuir
TL;DR: In this paper, the existence of photo-Kolbe reaction was confirmed by means of in situ measurements with flow electron spin resonance for deuterated acetic acid, and two reaction paths were deduced for methyl radical formation.
Abstract: The existence of methyl radicals in the photo-Kolbe reaction was confirmed by means of in situ measurements with flow electron spin resonance for deuterated acetic acid. From the dependence of the flow rate, two reaction paths were deduced for methyl radical formation. These were assigned to those caused by trapped holes and •OH radicals. It is suggested that the former path is dominant when platinum has not been loaded onto TiO2 powder.

Journal ArticleDOI
TL;DR: In this article, light-induced reactions of Si surfaces with carboxylic acids to generate Si ester-modified surfaces are studied, where the reaction proceeds by photoelectrochemical oxidation of porous or (100)-oriented single-crystal n-type Si in formic, acetic, or trifluoroacetic acid electrolyte solutions.
Abstract: Light-induced reactions of Si surfaces with carboxylic acids to generate Si ester-modified surfaces are studied. The reaction proceeds by photoelectrochemical oxidation of porous or (100)-oriented single-crystal n-type Si in formic, acetic, or trifluoroacetic acid electrolyte solutions. The reaction products at the porous Si surface are identified by Fourier-transform infrared (FTIR) spectroscopy. Derivatization with esters reduces the photoluminescence intensity of porous Si. X-ray photoelectron spectroscopy (XPS) of derivatized single-crystal Si is used to confirm the compositional and bonding information and to demonstrate that the same chemistry occurs at a single-crystal Si surface. A mechanism is proposed in which illumination of reverse-biased Si removes electron density from the Si surface, rendering Si−Si bonds susceptible to nucleophilic attack by carboxylic acid. The reaction has a marked dependence on light intensity and the Si surface can be photopatterned by illumination through a mask durin...

Journal ArticleDOI
TL;DR: In this article, a novel molecular recognition process using aromatic and aliphatic amino acids was studied using non-covalent processes such as hydrogen bonding, π−π, and hydrophobic interactions.
Abstract: Molecular recognition, via non-covalent processes such as hydrogen bonding, π−π, and hydrophobic interactions, is an important biological phenomenon for guests, such as drugs, proteins, and other important biological molecules with, for example, host DNA/RNA. We have studied a novel molecular recognition process using guests that encompass aromatic and aliphatic amino acids [l-alanine, l-glutamine (l-Gln), l-histidine, l-isoleucine (l-Ile), l-leucine (l-Leu), l-phenylalanine (l-Phe), l−proline, l-tryptophan (l-Trp), l-valine (l-Val)], substituted aromatic carboxylic acids [o-, m-, p-aminobenzoic acids (G1-3), benzoic acid (G4), phenylacetic acid (G5), p-methoxyphenylacetic acid (G6), o-methyoxybenzoic acid (G9), o-nitrobenzoic acid (G10)], and aliphatic carboxylic acids [cyclohexylacetic acid (G7), 1-adamantanecarboxylic acid (G8)] with supramolecular, bioorganometallic hosts, (η5-pentamethylcyclopentadienyl)rhodium (Cp*Rh)−nucleobase, nucleoside, and nucleotide cyclic trimer complexes, [Cp*Rh(9-methylade...

Journal ArticleDOI
TL;DR: Pseudomonas oleovorans was grown separately on 5-(4'-tolyl)valeric acid, 5-4'-ethylphenyl)-valeric acid and 5-( 4'-biphenyl)valerine acid, and either as the sole carbon source or as a co-efeed with either nonanoic acid or 5-phenylvalerines.
Abstract: Pseudomonas oleovorans was grown separately on 5-(4'-tolyl)valeric acid, 5-(4'-ethylphenyl)-valeric acid, 5-(4'-biphenyl)valeric acid, and 8-(4'-tolyl)octanoic acid either as the sole carbon source or as a coefeed with either nonanoic acid or 5-phenylvaleric acid. For polymer production, 5-(4'-tolyl)valeric acid was the most effective growth substrate of the five. It resulted in the production of poly-3-hydroxy-5-(4'-tolyl)valerate, a crystalline polymer with a glass transition temperature of 18 °C and a melting transition of 95 °C. This poly(3-hydroxyalkanoate) (PHA) is apparently the first example of a crystalline aromatic-containing bacterial PHA. When P. oleovorans was cofed an equimolar mixture of 5-phenylvaleric acid and 5-(4'-tolyl)valeric acid, the polymer produced contained 36 mol % of 3-hydroxy-5-phenylvalerate and 64 mol % of 3-hydroxy-5-(4'-tolyl)valerate, and it did not crystallize.

Journal ArticleDOI
TL;DR: In this article, the reactions of HCOOH and CH3COOH on CeO2(111) and CeO 2(100) were studied using temperature programmed desorption (TPD) and high resolution electron energy loss spectroscopy (HREELS).

Journal ArticleDOI
TL;DR: In this paper, the lipase-catalyzed stereoelective ring-opening polymerization of racemic α-methyl-β-propiolactone (MPL) was investigated.
Abstract: The lipase-catalyzed stereoelective ring-opening polymerization of racemic α-methyl-β-propiolactone (MPL) was investigated. Using the lipase PS-30 from Pseudomonas fluorescens, a direct route to optically active (S)-enriched poly(α-methyl-β-propiolactone), PMPL, was demonstrated. From a comparative study of different organic media, polymerizations conducted in toluene and heptane proceeded more rapidly than those carried out in dioxane. The enantiomeric ratios E in toluene, heptane, and dioxane were 4.1 ± 0.2, 0.9, and 2.0, respectively. Thus, from the point of view of reaction rates and enantioselectivity, toluene was found to be the preferred solvent. PMPL products prepared in toluene by PS-30 catalysis had Mn values from 2600 to 2900 g/mol and [α]25D +12.2° to +19.0° (c 0.9 g/dL, CHCl3). Analysis of the polymer chain end structure by 1H and 13C NMR showed that these products have hydroxyl and carboxylic acid termini. Based on the analysis of chain stereosequence distributions by 13C NMR, it was conclud...

Journal ArticleDOI
TL;DR: The reported series of aromatic coumarinic esters behaves as a new chemical family of selective alpha-chymotrypsin inhibitors.
Abstract: A series of esters and amides of 6-(chloromethyl)-2-oxo-2H-1-benzopyran-3-carboxylic acid were synthesized and evaluated in vitro for their inhibitory activity toward bovine α-chymotrypsin and human leukocyte elastase. Both series behaved as time-dependent inhibitors of α-chymotrypsin, but ester-type coumarins were clearly more efficient than the corresponding amides in inactivating the serine proteinase. The best inactivations were observed with “aromatic” esters, in particular with meta-substituted phenyl esters such as m-chlorophenyl 6-(chloromethyl)-2-oxo-2H-1-benzopyran-3-carboxylate, which appears to be one of the most powerful inactivators of α-chymotrypsin yet reported (kinact/KI = 760 000 M-1 s-1 at pH 7.5 and 25 °C). Usually, the coumarin derivatives failed to inhibit significantly human leukocyte elastase. As a result, the reported series of aromatic coumarinic esters behaves as a new chemical family of selective α-chymotrypsin inhibitors.

Journal ArticleDOI
TL;DR: In this article, the supramolecular structure of both compounds is governed by Au-Au interactions [2a, Au--Au 3.3186(5) A] and hydrogen bonding through the carboxylic acid groups.

Journal ArticleDOI
TL;DR: In this paper, a selective precolumn derivatization reaction was introduced and evaluated in the fluorescence labeling of phenoxy acid herbicides with 7-aminonaphthalene-1,3-disulfonic acid (ANDSA).
Abstract: A novel, selective precolumn derivatization reaction was introduced and evaluated in the fluorescence labeling of phenoxy acid herbicides with 7-aminonaphthalene-1,3-disulfonic acid (ANDSA). The ANDSA-phenoxy acid derivatives were readily detected by capillary electrophoresis/laser-induced fluorescence (CE-LIF) at 0.2 ppb, a concentration at which environmental herbicide samples are expected to occur. The precolumn derivatization was very quantitative (99.7% yield) and produced stable derivatives and no side products. Furthermore, the ANDSA-phenoxy acid herbicide enantiomers exhibited higher chiral resolution than their underivatized counterparts in the presence of cyclodextrin (CD) in the running electrolyte. Several native and modified CDs were investigated in the enantiomeric separation of chiral phenoxy acid herbicides. The best enantioselectivity was achieved when 2,3,6-tri-O-methyl-β-cyclodextrin (TM-β-CD) was used as the chiral selector. To effect the enantiomeric resolution of a large number of AN...

Patent
15 Apr 1996
TL;DR: In this paper, a process for hydrogenating aldehydes, ketone and carboxylic acids using these shaped catalysts is described. But the process is not suitable for hydrogenation of nitro aromatic compounds.
Abstract: Shaped catalyst compositions are disclosed comprising (i) at least one metal selected from the group consisting of copper, manganese, zinc, nickel, cobalt and iron, (ii) calcium silicate and (iii) at least one clay material. Also disclosed are a process for preparing the foregoing shaped compositions and a process for hydrogenating aldehydes, ketone, carboxylic acids, carboxylic acid esters and nitro aromatic compounds using these shaped catalysts.

Journal ArticleDOI
TL;DR: In this paper, a chiral alkanoic acid was prepared with up to 52% excess of the (S) enantiomer by hydrogenating an α,β-unsaturated carboxylic acid with a cinchonidine-Pd/Al2O3 catalyst system.
Abstract: A chiral alkanoic acid was prepared with up to 52% excess of the (S) enantiomer by hydrogenating anα,β-unsaturated carboxylic acid with a cinchonidine-Pd/Al2O3 catalyst system. Favourable conditions are: high surface hydrogen concentration (⩾ 60 bar hydrogen pressure, low catalyst concentration and apolar solvents), near ambient temperature and a cinchonidine/reactantmolar ratio of at least 0.4 mol%. It is proposed that high hydrogen solubility and the presence of 2-methyl-2-pentenoic acid reactant as dimers are advantageous for enantiodifferentiation.

Journal ArticleDOI
TL;DR: In the presence of carboxylic acids, the adduct formed between triphenylphosphine and diisopropyl azodicarboxylate reacts to form mono- and bis-acylated hydrazides and the car boxylic acid anhydrides, with weaker acids reacting much faster than stronger acids.
Abstract: In the presence of carboxylic acids, the adduct formed between triphenylphosphine and diisopropyl azodicarboxylate reacts to form mono- and bis-acylated hydrazides and the carboxylic acid anhydrides. These products are formed via attack of the carboxylate on the triphenylphosphonium group of the adduct, with weaker acids reacting much faster than stronger acids. This provides an explanation for the observation in the literature that acids stronger than acetic acid, such as 4-nitrobenzoic acid and chloroacetic acid, provide better yields in esterification reactions, since reaction of the alcohol with the phosphonium group of the adduct is more rapid than the competing reaction of the carboxylate for the phosphonium group.

Journal ArticleDOI
TL;DR: In this article, Fourier transform infrared (FT-IR) spectroscopy was used to study the kraft paper treated with poly(maleic acid) and 1,2,3,4-butanetetetracarboxylic acid.
Abstract: Polycarboxylic acids have been used as cross-linking agents for cellulose to increase the wet strength of paper. In this research, we applied Fourier transform infrared (FT-IR) spectroscopy to study the kraft paper treated with poly(maleic acid) and 1,2,3,4-butanetetracarboxylic acid. FT-IR spectroscopy is used to measure the carboxyl of a polycarboxylic acid and ester on the treated paper. The ester carbonyl band intensity and the carbonyl band intensity ratio (ester/carboxylate) are used for the evaluation of the effectiveness of a polycarboxylic acid for cross-linking cellulose on the paper. The correlation between the ester carbonyl band intensity and the wet strength improvement of the treated paper reveals that the increase in the paper wet strength by a polycarboxylic acid is the result of ester cross-linking of cellulosic fibers and molecules. We identified a five-membered cyclic anhydride intermediate formed on the paper during the curing processes. The infrared spectroscopy data support the reac...

Journal ArticleDOI
TL;DR: The alpha-benzylaminobenzylphosphonic acid, with an IC50 = 4 nM, exhibited a 3500-fold improvement in potency over the carbon analogue, alpha-phenylethyl, which may be due to a combination of four favorable interactions including those with the phosphate binding region.

Journal ArticleDOI
TL;DR: In this paper, aziridine 2a, prepared from sulfinimine 1 via a Darzens-type condensation, undergoes a highly regio-and stereocontrolled ring-opening to give α-methylphenylalanine and β-phenylserine in high enantiomeric purity.

Journal ArticleDOI
TL;DR: In this paper, a single crystal pulsed neutron diffraction study of benzoic acid has been carried out at four temperatures, 20, 50, 100 and 175 K. This has allowed accurate site occupancies to be obtained for the hydrogen atom disorder in the hydrogen bonded carboxylic acid dimer motif.