591-81-1

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Platinum(II) ion, in the presence of platinum(IV), is found to catalyse the hydroxylation of unactivated C-H bonds of aliphatic carboxylic acids in water with the following order of reactivity: α-C-H δ-C-H ca. ε-C-H.

A nicotinamide adenine dinucleotide (NADH)-dependent redox-neutral convergent cascade composed of a recently discovered type II flavin-containing monooxygenase (FMO?E) and horse liver alcohol dehydrogenase (HLADH) has been established. Two model reaction cascades were analyzed for the synthesis of γ-butyrolactone and chiral bicyclic lactones. In the former cascade, all substrates were converted into one single product γ-butyrolactone with high atom efficiency. More than 130 mM γ-butyrolactone were obtained when applying 100 mM cyclobutanone and 50 mM 1,4-butanediol in this cascade. In the second cascade where bicyclo[4.2.0]octan-7-one and cis-1,2-cyclohexanedimethanol were coupled, the ketone substrate was converted to the corresponding normal lactone with an ee value of 89–74% (3aS, 7aS) by FMO?E alone and the abnormal lactone with an ee value of >99% (3aR, 7aS) was formed by both HLADH and FMO?E. (Figure presented.).

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The invention belongs to the technical field of drug small molecules, and particularly discloses a brand-new di-(benzimidazole)-1, 2, 3-triazole derivative as well as preparation and application of the brand-new di-(benzimidazole)-1, 2, 3-triazole derivative. The research finds that the brand new compound has an excellent drug effect and low toxic and side effects on the aspect of inflammatory dermatosis, and has a good application prospect in the aspect of drug development of the inflammatory dermatosis.

The practical application of Shilov-type Pt catalysis to the selective hydroxylation of terminal aliphatic C?H bonds remains a formidable challenge, due to difficulties in replacing PtIV with a more economically viable oxidant, particularly O2. We report the potential of employing FeCl2 as a suitable redox mediator to overcome the kinetic hurdles related to the direct use of O2 in the Pt reoxidation. For the selective conversion of butyric acid to γ-hydroxybutyric acid (GHB), a significantly enhanced catalyst activity and stability (turnover numbers (TON)>30) were achieved under 20 bar O2 in comparison to current state-of-the-art systems (TON0 was prevented by the addition of monodentate pyridine derivatives, such as 2-fluoropyridine, but also by introducing varying partial pressures of N2 in the gaseous atmosphere. Finally, stability tests revealed the involvement of PtII and FeCl2 in catalyzing the non-selective overoxidation of GHB. Accordingly, in situ esterification with boric acid proved to be a suitable strategy to maintain enhanced selectivities at much higher conversions (TON>60). Altogether, a useful catalytic system for the selective hydroxylation of primary aliphatic C?H bonds with O2 is presented.

Carboxylic acid reductases (CARs) catalyze the reduction of a broad range of carboxylic acids into aldehydes, which can serve as common biosynthetic precursors to many industrial chemicals. This work presents the systematic biochemical characterization of five carboxylic acid reductases from different microorganisms, including two known and three new ones, by using a panel of short-chain dicarboxylic acids and hydroxy acids, which are common cellular metabolites. All enzymes displayed broad substrate specificities. Higher catalytic efficiencies were observed when the carbon chain length, either of the dicarboxylates or of the terminal hydroxy acids, was increased from C2 to C6. In addition, when substrates of the same carbon chain length are compared, carboxylic acid reductases favor hydroxy acids over dicarboxylates as their substrates. Whole-cell bioconversions of eleven carboxylic acid substrates into the corresponding alcohols were investigated by coupling the CAR activity with that of an aldehyde reductase in Escherichia coli hosts. Alcohol products were obtained in yields ranging from 0.5 % to 71 %. The de novo stereospecific biosynthesis of propane-1,2-diol enantiomer was successfully demonstrated with use of CARs as the key pathway enzymes. E. coli strains accumulated 7.0 mm (R)-1,2-PDO (1.0 % yield) or 9.6 mm (S)-1,2-PDO (1.4 % yield) from glucose. This study consolidates carboxylic acid reductases as promising enzymes for sustainable synthesis of industrial chemicals.

Fe2O3/Al-MCM-41 nanocomposite catalysts were designed and fabricated to upgrade microalgae hydrothermal liquefaction (HTL)-derived biocrude and its model compounds (palmitic acid and glutamic acid) in the absence of hydrogen. The Fe

Titania-supported monometallic and bimetallic Cu-Co catalysts were prepared using (co)impregnation and studied for the hydrogenation of γ-butyrolactone (GBL) to 1,4-butanediol (BDO) at temperatures from 100 to 180 °C and a hydrogen pressure of 3.4 MPa. The highest catalytic activity occurred at a Cu:Co atomic ratio of 1:9 (Cu0.1Co0.9/TiO2), and a 95% yield of BDO was obtained. Characterization results showed mainly small nanoparticles (average size 2.6 nm) for pure Cu/TiO2, large particles (～19.8 nm) for pure Co/TiO2, and a bimodal particle size distribution of both small (～2.3 nm) and large (～16.5 nm) particles for the bimetallic catalyst with a Cu:Co ratio of 1:1. The addition of ～10 mol % Cu to Co/TiO2 increased the reducibility of the Co and resulted in the formation of core-shell CuCo bimetallic nanoparticles with a Co-rich core and Cu-rich shell. GBL hydrogenation in liquid ethanol and water produced an ester (ethyl 4-hydroxybutanoate) and a carboxylic acid (4-hydroxybutanoic acid) as the major products, respectively. GBL hydrogenation in 1,4-dioxane likely went through a 2-hydroxytetrahydrofuran (2-HTHF) intermediate. The 2-HTHF underwent facile ring-opening tautomerization to 4-hydroxybutanal (4-HB), followed by rapid hydrogenation to BDO at a reaction rate up to 700 times faster than GBL hydrogenation. The Cu0.1Co0.9/TiO2 catalyst maintained the BDO selectivity and about 80% of initial activity for GBL hydrogenation after 150 h time on stream in a continuous flow reactor.

PROBLEM TO BE SOLVED: To provide a reaction catalyst having a high reaction selectivity and being recyclable in a peroxidation reaction using a carbonyl compound, and to provide a method for highly efficiently producing, for example, ester, lactone and formyloxy compounds or derivatives thereof by subjecting a carbonyl compound to a peroxidation reaction using the reaction catalyst.SOLUTION: A specific tin-containing catalyst can be used for a peroxidation reaction of a carbonyl compound, and a recyclable specific tin-containing catalyst is reusable for the reaction. A method for producing an oxide carries out a peroxidation reaction of a carbonyl compound in the presence of the tin-containing catalyst or the tin-containing recyclable catalyst.

Amino acids have huge potential as platform chemicals in the biobased industry. Pd-catalyzed decarboxylation is a very promising route for the valorization of these natural compounds derived from protein waste or fermentation. We report that the highly abundant and nonessential amino acid L-proline is very reactive in the Pd-catalyzed decarboxylation. Full conversions are obtained with Pd/C and different Pd/MeOx catalysts; this allowed the identification of the different side reactions and the mapping of the reaction network. Due to the high reactivity of pyrrolidine, the selectivity for pyrrolidine was initially low. By carefully modifying Pd/ZrO2 with Pb in a controlled mannervia two incipient wetness impregnation stepsthe selectivity increased remarkably. Finally, a thorough investigation of the reaction parameters resulted in an increased activity of this modified catalyst and an even further enhanced selectivity under a low H2 pressure of 4 bar at 235 °C in water. This results in a very selective and sustainable production route for the highly interesting pyrrolidine.

Natural martite microparticles (NMMs) were prepared with a high energy planetary ball mill to form a nanocatalyst for a Fenton-like process. Martite nanoparticles (MNs) of different scales are formed when the milling time ranges from 1 to 5 h at the milling speed of 300 rpm. The catalytic performances of MNs are higher than the NMMs for the degradation of acid blue 5 (AB5) in a heterogeneous Fenton-like process. The NMMs and the MNs were characterized by SEM, EDX, BET, XRD and FT-IR analyses. The size distribution of the 5 h milled martite nanoparticles (MN3) is in the range of 20 nm to 100 nm, and these have the highest surface area (19.23 m2 g-1). The influence of the main operational parameters, including initial pH, MN3 dosage, H2O2 and initial dye concentration, were investigated on the AB5 degradation. The treatment process obeys pseudo first order kinetics and some of the degradation intermediates were recognized by the GC-MS method. The environmentally-friendly production of the MNs, low amount of leached iron and repeated catalyst usage are the significant advantages of this research. Finally, an artificial neural network (ANN) is expanded to estimate the degradation efficiency of AB5 on the basis of the experimental results, which indicates the appropriate performance (R2 = 0.955).

This study discussed the catalytic cracking process of cellulose in ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([bmim]OTF) under 180 °C, 240 °C and 340 °C, found that [bmim]OTF is an effective catalyst which can effectively reduce the pyrolysis temperature(nearly 200 °C) of the cellulose. FRIR, XRD and SEM were used to analyze the structure characterization of fiber before and after the cracking; GC-MS was used for liquid phase products analysis; GC was used to analyze gas phase products. The results showed that the cellulose pyrolysis in [bmim]OTf mainly generated CO2, CO and H2, also generated 2-furfuryl alcohol, 2,5-dimethyl-1,5-diallyl-3-alcohol, 1,4-butyrolactone, 5-methyl furfural, 4-hydroxy butyric acid, vinyl propionate, 1-acetoxyl group-2-butanone, furan formate tetrahydrofuran methyl ester liquid product, and thus simulated the evolution mechanism of cellulose pyrolysis products based on the basic model of cellulose monomer.

This document describes biochemical pathways for producing 4-hydroxybutyrate, 4-aminobutyrate, putrescine or 1,4-butanediol by forming one or two terminal functional groups, comprised of amine or hydroxyl group, in a C5 backbone substrate such as 2-oxoglutarate or L-glutamate.

The invention provides non-naturally occurring microbial organisms comprising a 1,4-butanediol (BDO) pathway comprising at least one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO. The invention additionally provides methods of using such microbial organisms to produce BDO.

A method of producing lactone by converting an aqueous solution including hydroxycarboxylic acid or dicarboxylic acid to lactone under an acid condition and in the presence of a water immiscible solvent.

Highly dispersed palladium nanoclusters incorporated on amino-functionalized silica sphere surfaces (Pd/SiO2-NH2) were fabricated by a simple one-pot synthesis utilizing 3-(2-aminoethylamino)propyltrimethoxysilane (AAPTS) as coordinating agent. Uniform palladium nanoclusters with an average size of 1.1 nm can be obtained during the co-condensation of tetraethyl orthosilicate and AAPTS owing to the strong interaction between palladium species and amino groups in AAPTS. The palladium particle size can be controlled by addition of AAPTS and plays a significant role in the catalytic performance. The Pd/SiO2-NH2 catalyst exhibits high catalytic activity for succinic acid hydrogenation with 100% conversion and 94% selectivity towards γ-butyrolactone using 1,4-dioxane as solvent at 240°C and 60 bar for 4 h. Moreover, the Pd/SiO2-NH2 catalyst is robust and readily reusable without loss of its catalytic activity.

In order to recycle nitrogen from nitrogen-rich waste streams, particularly protein waste, we studied the decarboxylation of pyroglutamic acid and glutamic acid in a one-pot reaction to bio-based 2-pyrrolidone. After the screening of a wide range of supported Pd and Pt catalysts, 5 wt% Pd/Al2O3 displayed the highest yield (70%) and selectivity (81%) for the decarboxylation of pyroglutamic acid in water at 250°C and under an inert atmosphere. Side products originate from consecutive reactions of 2-pyrrolidone; different reaction pathways are proposed to explain the presence of degradation products like propionic acid, γ-hydroxybutyric acid, γ-butyrolactone and methylamine. An extensive study of the reaction parameters was performed to check their influence on selectivity and conversion. This heterogeneous catalytic system was successfully extended to the conversion of glutamic acid.

An inexpensive protocol for the conversion of -C6H4R into -COOH groups using Co(ii)-Oxone mixture as the catalytic system is described. A series of substrates containing substituted and non-substituted phenyl groups could be selectively converted into carboxylic acids. Initial mechanistic data have been provided.

The oxidation of four butanediols under base-free conditions has been investigated using a set of Au, Pd and Pt catalysts prepared using sol-immobilization. The supported nanoparticles are found to be active with bimetallic alloys having much higher activity when compared with the monometallic counterparts. In general the AuPt catalysts are the most active and in all cases the corresponding C4 oxidation products were observed with high selectivity; sequential reaction of these products leads to the formation of acetic acid as an undesired by-product.

The oxidation of four butanediols under base-free conditions has been investigated using a set of Au, Pd and Pt catalysts prepared using sol-immobilization. The supported nanoparticles are found to be active with bimetallic alloys having much higher activity when compared with the monometallic counterparts. In general the AuPt catalysts are the most active and in all cases the corresponding C4 oxidation products were observed with high selectivity; sequential reaction of these products leads to the formation of acetic acid as an undesired by-product.

The first fluorescent sensor (GHB Orange) for date rape drug GHB was developed. It exhibits the fluorescence quenching property for GHB and allows its detection in various drinks. The interaction mechanism was elucidated as intramolecular charge transfer induced by a hydrogen bond. This discovery will help in solving the drug facilitated sexual assault problems.

A multistep enzyme catalysis was successfully implemented to produce long-chain α,ω-dicarboxylic and ω-hydroxycarboxylic acids from renewable fatty acids and plant oils. Sebacic acid as well as ω-hydroxynonanoic acid and ω-hydroxytridec-11-enoic acid were produced from oleic and ricinoleic acid. Copyright

Picking up the thread: The macrocycle bis-p-xylyl[26]crown-6 is capable of forming pseudorotaxane-like structures with single, nonconjugated urea or amide moieties when assisted by templating Na+ ions (see example). By using this approach, rotaxanes were synthesized with glycine residues or the repeating unit of nylon-6,6 as key components in the threadlike units. Copyright

A facile biomimetic method for rapid oxidation of alcohols to carbonyl compounds using dioxygen as the primary oxidant catalyzed by metallodeuteroporphyrin dimethyl ester [M(DPDME)] in acetonitrile as the reaction solvent and isobutylaldehyde as cocatalyst has been investigated. Among the M(DPDME) catalysts, where M = Fe(III), Co(II), Mn(III), Ni(II), Cu(II), and Zn(II), cobalt porphyrin was found to be the most active and effective catalyst. The catalytic system was widely used in the oxidation of various alcohols and especially exhibited excellent activity for oxidation of aromatic alcohols under mild conditions. Moreover, M(DPDME) was prepared from an improved facile method by chemical modification of natural hemin and an alternative mechanism for the aerobic oxidation of alcohols has been proposed and discussed.

The conversion of 1,4-butanediol (1,4-BD) to gamma-hydroxybutyric acid (GHB), a drug of abuse, is most probably catalyzed by alcohol dehydrogenase, and potentially by aldehyde dehydrogenase. The purpose of this study was to investigate the degradation of 1,4-BD in cytosolic supernatant of human liver in vitro, and to verify involvement of the suggested enzymes by means of gas chromatography-mass spectrometry. The coingestion of 1,4-BD and ethanol (EtOH) might cause complex pharmacokinetic interactions in humans. Therefore, the effect of EtOH on 1,4-BD metabolism by human liver was examined in vitro. Additionally, the influence of acetaldehyde (AL), which might inhibit the second step of 1,4-BD degradation, was investigated. In case of a 1,4-BD intoxication, the alcohol dehydrogenase inhibitor fomepizole (4-methylpyrazole, FOM) has been discussed as an antidote preventing the formation of the central nervous system depressing GHB. Besides FOM, we tested pyrazole, disulfiram, and cimetidine as possible inhibitors of the formation of GHB from 1,4-BD catalyzed by human liver enzymes in vitro. The conversion of 1,4-BD to GHB was inhibited competitively by EtOH with an apparent K i of 0.56 mM. Therefore, the coingestion of 1,4-BD and EtOH might increase the concentrations and the effects of 1,4-BD itself. By contrast AL accelerated the formation of GHB. All antidotes showed the ability to inhibit the formation of GHB. In comparison FOM showed the highest inhibitory effectiveness. Furthermore, the results confirm strong involvement of ADH in 1,4-BD metabolism by human liver.

Voltage-dependent potassium channels (Kv) are involved in various cellular signalling processes by governing the membrane potential of excitable cells. The cytosolic face of these α subunit-containing channels is associated with β subunits that can modulate channel responses. Surprisingly, the β subunit of the mammalian Kv1 channels, Kvβ2, has a high level of sequence homology with the aldo-keto reductase (AKR) superfamily of proteins. Recent studies have shown that Kvβ2 can catalyze the reduction of aldehydes and, most significantly, that channel function is modulated when Kvβ2-bound NADPH is concomitantly oxidized. As a result, the redox chemistry of this subunit is crucial to understanding its role in K+ channel modulation. The present study has extended knowledge of the substrate profile of this subunit using a single turnover fluorimetric assay. Kvβ2 was found to catalyse the reduction of aromatic aldehyde substrates such as 2, 3 and 4-nitrobenzaldehydes, 4-hydroxybenzaldehyde, pyridine 2-aldehyde and benzaldehyde. The presence of an electron withdrawing group at the position para to the aldehyde in aromatic compounds facilitated reduction. Aliphatic aldehydes proved to be poor substrates. We devised a simple HPLC-based assay to identify Kvβ2 reaction products. Using this assay we showed, for the first time, that Kvβ2 can catalyze a slow aldehyde dismutation reaction using 4-nitrobenzaldehyde as substrate and have identified the products of this reaction. The ability of Kvβ2 to carry out both an aldehyde reduction and a dismutation reaction is discussed in the light of current thinking on the role of redox chemistry in channel modulation.

N-Methylpyrrolidone (NMP) is an industrial solvent that is currently based on fossil resources. In order to prepare it in a biobased way, the possibility to synthesize NMP from γ-aminobutyric acid (GABA) was investigated, since GABA can be obtained from glutamic acid, an amino acid that is present in many plant proteins. Cyclization of GABA to 2-pyrrolidone and subsequent methylation of 2-pyrrolidone to NMP was achieved in a one-pot procedure, using methanol as the methylating agent and a halogen salt (i.e. ammonium bromide) as a catalyst. A selectivity above 90% was achieved, as well as a high conversion. Methylation of 2-pyrrolidone could also be done with dimethyl carbonate, but then the selectivity for NMP was less (67%).

This invention relates to a process for catalytically hydrogenating a hydrogenatable precursor in contact with a hydrogen-containing gas and a hydrogenation catalyst comprising one or more active hydrogenation catalyst components on a support comprising titanium dioxide in the rutile crystalline phase to produce 1,4-butanediol and, optionally, gamma-butyrolactone and/or tetrahydrofuran.

The preparation of the title compounds was achieved via the 'azirine/oxazolone method' starting from the corresponding γ-hydroxy acids. Upon subjecting the γ-hydroxy-N-[1-(dimethylcarbamoyl)-ethyl] butanamides 4 to the so-called 'direct amide cyclization' (DAC) conditions, chlorinated acids 11 or imino lactones 12 were obtained as the sole products instead of the expected cyclodepsipeptides A or their cyclodimers (Scheme 4). Variation of the substituents in 4 did not affect the outcome of the reaction and a mechanism for the formation of both products from the intermediate oxazolone 13 has been proposed. Under the acidic conditions of the DAC, the imino lactones are formed as their HCl salts 12, which, in polar solvents or on silica gel, reacted further to give the chlorinated acids 11. Stabilization of the imino lactones was achieved by increasing the substitution in the five-membered ring, and their structure, in the form of the hydrochlorides, was established independently by X-ray crystallography (Fig. 4). A derivative 15 of the imino lactone 12a was prepared by the reaction with the 2H-azirin-3-amine 10a; its structure was also established by an X-ray crystal-structure determination (Fig. 3). Furthermore, the structures of the ω-chloro acids 11a and 11b were determined by X-ray crystallography (Fig. 2).

(Chemical Equation Presented) The behavior of lactones in their hydrolysis reactions is a good indicator of their reactivity as electrophilic molecules. The hydrolysis of four- to six-membered lactones was investigated in neutral (water) and slightly acid media and in water/dioxane media. The following conclusions were drawn: (i) The reactivity of β-propiolactone in neutral water is more than four times greater than that of β-butyrolactone, due to the flow of charge caused by the latter's methyl substituent. Reactivity is enthalpy-controlled. (ii) The reactivity of β-lactones diminishes in water/dioxane media when the percentage of dioxane increases. The increase in the dioxane percentage relaxing the intermolecular hydrogen bonds in the ordered structure of the water reduces ΔH# and simultaneously increases the -ΔS# value. (iii) An inverse solvent kinetic isotope effect in the acid-catalyzed hydrolysis of γ-butyrolactone and δ-valerolactone was observed, this being indicative of acyl cleavage. (iv) The ΔH# and ΔS# values permit discrimination between alkyl and acyl cleavage, (v) A correlation was found between the chemical reactivity of lactones and their carcinogenic activity. (vi) The results suggest that orally ingested γ-butyrolactone remains largely in its nonhydrolyzed form in the stomach before passing into the blood. (vii) The concentration equilibrium constant of GHB formation at human body temperature is Keq (37°C) = 0.40. (viii) Study of GHB formation shows that, contrary to earlier results, this is an endothermic process, with ΔrH= 3.6 kJ mol-1.

4-Hydroxybutyryl-CoA dehydratase from Clostridium aminobutyricum catalyses the reversible dehydration of its substrate 4-hydroxybutyryl-CoA (4-HB-CoA) to crotonyl CoA. The enzyme contains one [4Fe-4S]2+ cluster and one flavin adenine dinucleotide (FAD) molecule per homotetramer. Incubation of the enzyme with its substrate under equilibrium conditions followed by freezing at 77 K induced the EPR-spectrum of a neutral flavin semiquinone (g = 2.005, linewidth 2.1 mT), while at 10 K additional signals were detected. In an attempt to characterize these signals, 4-HB-CoA molecules specifically labeled with 13C have been synthesized. This was achieved via 13C- labeled γ-butyrolactones, which were obtained from 13C-labeled bromoacetic acids by efficient synthetic routes. Incubation of the 13C-labeled 4-hydroxybutyrate-CoA molecules with 4-hydroxybutyryl-CoA dehydratase did not lead to marked broadening of the signals.

A novel L-pantolactone hydrolase, Lph, from Agrobacterium tumefaciens Lu681 was characterized, which stereospecifically hydrolyses L-pantolactone to L-pantoic acid yielding D-pantolactone with > 95% enantiomeric excess. The enzyme was found to be a 30 kDa-Zn2+-hydrolase with a Km for L-pantolactone of 7 mM and a Vmax of 30 U/mg. The corresponding lph gene was identified as an 807 bp ORF and cloned into E. coli. It was overexpressed under control of Ptac and Prha yielding enzyme activities of up to 600 U/g dry weight. Resolution of D,L-pantolactone in repeated batches with isolated Lph and enzyme recovery by membrane filtration gave D-pantolactone with 50% yield and 90-95% ee over 6 days. Covalent immobilization to EupergitC led to a stable biocatalyst easy to handle in a repeated batch production of D-pantolactone. Further improvements in the activity of Lph were achieved by directed evolution of the enzyme. Activities of mutants F62S, K197D and F100L were increased 2.3, 1.7, and 1.5 fold, respectively.

In a mixture of trifluoroacetic acid and water, the combination of metallic palladium and copper chloride catalyzes the hydroxylation of remote primary C-H bonds of a variety of acids, alcohols, and aliphatic halides, in the presence of carbon monoxide and dioxygen. Experiments suggest that the principal role of metallic palladium is to generate hydrogen peroxide in situ and that the species responsible for the remote hydroxylation of the substrate by hydrogen peroxide is copper chloride. The unusual preference for the catalytic hydroxylation of primary C-H bonds was also found in an experiment involving competition between ethane and either cumene or p- isopropylbenzoic acid: even though the solution concentration of ethane was significantly lower than the competing substrate, the vast majority of the oxidation product (ethanol) was derived from ethane. In the reactions studied, acetic acid and formic acid were formed through C-C cleavage steps. An examination of the site of C-C cleavage in propionic acid indicated that both C-C bonds were being broken.

Allocyathin B2 has been synthesized using aldol reactions for construction of rings A and B, introduction of the side chain for ring B, cyclization of the acetyl group into a lactone, and construction of the seven-membered diene aldehyde during the last step.

Dermatosis is treated by a method comprising topically applying an effective amount of an ester of L-carnitine or an acyl L-carnitine with a hydroxy carboxylic acid selected from the group consisting of α-hydroxybutyric acid, α-hydroxyisocaproic acid, α-hydroxyisovaleric acid, malic acid and tartronic acid, to a patient in need thereof.

Compounds of formula (I): STR1 [wherein: X represents an unsubstituted or substituted indolyl, indolinyl, azaindolyl, azaindolinyl, imidazopyridyl or imidazopyrimidinyl group; Y represents an oxygen or sulfur atom; Z represents a 2,4-dioxothiazolidin-5-ylidenylmethyl, 2,4-dioxothiazolidin-5-ylmethyl, 2,4-dioxooxazolidin-5-ylmethyl, 3,5-dioxooxadiazolidin-2-ylmethyl or N-hydroxyureidomethyl group; R represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a hydroxy group, a nitro group, an aralkyl group or a unsubstituted or substituted amino group; and m is an integer of from 1 to 5] have hypoglycemic and anti-diabetic activities.

The use is disclosed of esters of L-carnitine and acyl L-carnitines with hydroxyacids for producing pharmaceutical compositions suitable to be topically applied for treating dermatoses such as ichthyosis and psoriasis.

The enthalpies of hydrolysis of the monocyclic lactones from γ-butyrolactone to tridecanolactone were determined calorimetrically, and the acyclic ethyl having the number of atoms were studied in the fashion. The enthalpies of reduction of the lactones to the corresponding α,ω-alkanediols with lithium triethylborohydride also were determined. The enthalpies of formation of the lactones and the ethyl esters were derived from these data. They were converted to values for the gas phase by measuring the enthalpies of vaporization of ethyl esters and of lactones. In the of γ-butyrolactone and δ-valerolactone, the enthalpies of formation were in good accord with the previously reported values determined via combustion calorimetry. The strain energies of the lactones were obtained via isodesmic reactions. Valerolactone had a strain energy of 11 kcal/mol, and the largest strain energy was found with octanolactone (13 kcal/mol). The conformations of γ-butyrolactone and δ-valerolactone were studied via MP2/6-31G* geometry optimizations, and the conformations of the other lactones were studied with use of the molecular mechanics program MM3. The energies of the lactones estimated via molecular mechanics were compared with the experimental results.

The action of sodium nitrite on various amino-acids was re-examined in conditions approximating to a biological medium. 13C-NMR provides evidence of the existence of intramolecular ring closures and the formation of 5-membered rings with ornithine, citrulline and arginine.The reaction of cystine shows the opening of the sulphur bridges, whereas cysteine leads to the formation of carboxy-thiiran and 3-sulpho-lactic acid.The hydrolysis of the amide bonds of asparagine and glutamine is complete whereas the peptides studied - carnosine and aspartam - do not undergo hydrolysis of the peptide linkage.However, the first deamination of glutathion (γ-Glu-Cys-Gly) induces the peptide link to be broken and a cyclization with the formation of lactone to occur.A second deamination takes place on the cysteinyl residue released and allows the formation of a thiiran by intramolecular cyclization with the thiol group.The formation of thiiran was also observed with oxidized glutathion which has an S-S bridge.Finally, the formation of nitrosamines was detected by 15N-NMR during the reaction of sodium nitrite with two commercial products available to the general public.

Polypeptides and derivatives thereof containing nor-statine and nor-cyclostatine are useful for inhibiting the angiotensinogen-cleaving action of the enzyme renin.

An improved procedure for the employment of NaBH4 in the reduction of ester function is described.