Synthesis of N-alkyloamino- or arylo-imide derivatives of succinic acid

10 new imide derivatives of phenylsuccinic acid possessing alkyloamine, alkyloaryl or aryl groups at nitrogen atom were obtained.     

Selective leaching kinetics and upgrading of low-grade calcareous phosphate rock in succinic acid

Selective leaching kinetics of calcareous phosphate rock in succinic acid solution was investigated. Using a known particle size range of the sample, liquid/solid ratio and acid concentration, the influence of various reaction temperatures was studied in order to elucidate the kinetics of calcareous material in the rock. The leaching rate increased with increasing temperature. A kinetic model was suggested to describe the selective leaching process of calcareous material analyzing the kinetic data. The selective leaching curves were evaluated in order to check the validity of shrinking core models for liquid–solid systems. The experimental data were tested by graphical and statistical methods and it was found that the leaching of calcareous material in the rock was controlled by chemical reaction, i.e., 1 − (1 − x)^1/3 = 1.47 × 10⁶e^−64.92/RTt. The apparent activation energy of the leaching process was found as 64.92 kJ mol⁻¹ over the reaction temperature range from 313 to 353 K.     

The effect of the bacterial product, succinic acid, on neutrophil bactericidal activity

Patients with paroxysmal atrial fibrillation (AF) have greater overall P wave magnitude than control subjects, but the temporal localization of the increased energy is unknown. P wave spectral turbulence has not been investigated in such patients, and the optimum methodology for studying P wave signals has not been defined. This study, therefore, applied both spectrotemporal and spectral turbulence analyses to the signal-averaged P waves of patients with paroxysmal AF and to representative control subjects. Group A, 58 persons without cardiopulmonary disease (24 patients with paroxysmal AF, 34 control subjects), and group B, 57 with such disease (31 patients with paroxysmal AF, 26 control subjects), were studied. Spectral analysis was performed on a windowed 64-ms data segment that was advanced through the P wave in 2-ms steps. Spectral turbulence was measured from differentiated 24-ms data segments, by either cross-correlation between adjacent spectra, or differentiation of adjacent spectral coefficients over time (SV, spectral velocity). Patients had greater maximum P wave energy than control subjects, between 80-150 Hz for group A (means, 0.9 vs 0.7 microV2 x s), and 20-150 Hz for group B (means, 22.4 vs 16.3 microV2 x s). Spectral velocity was greater in patients with paroxysmal AF than in control subjects in both groups (group A: Peak SV, 11.6 vs 7.4 microV2 and group B: Peak SV, 12.0 vs 7.6 microV2). Increased energy and SV were reported in the central P wave. Spectrotemporal analysis suggested abnormal atrial activation in the central P wave associated with paroxysmal AF. A localized abnormality in atrial electrophysiology may cause the electrogenesis of the arrhythmia.     

Effects of dietary supplementation with n-3 fatty acid ethyl esters on coccidiosis in chickens

The ethyl esters of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids were added to a broiler starter diet singly or in combination [as bulk purified ethyl ester concentrate from menhaden oil (n3FAC)] in quantities similar to those found in a diet supplemented with 5% menhaden oil (MO). Diets were fed to chickens from 1 d of age through 3 wk of age. At 2 wk of age, the chickens were infected with Eimeria tenella, Eimeria acervulina, or Eimeria maxima. At 6 d postinfection (PI), the effects of the diets were assessed on weight gains, plasma carotenoids, gross lesion scores, and histological parasite scores in gut cross sections, or oocyst output. Significant ameliorating effects of diet on lesion scores and parasite scores were only seen in E. tenella infections and were only produced by the n3FAC and MO supplements. These two supplements, which contained higher molar concentrations of double bonds than the other supplements, also significantly reduced plasma carotenoids in uninfected chickens, indicating that they promoted a state of oxidative stress. These results are consistent with previous reports on the interaction of coccidiosis with dietary n-3 fatty acids and strengthen the hypotheses that dietary-induced oxidative stress is an effective deterrent against cecal coccidiosis in chickens.     

Preparation of optically active succinic acid derivatives. III. Regioselective condensation reactions of optically active 2-substituted succinic acids with diimidazolide

We investigated the large scale synthesis of monocalcium bis [(2S)-2-benzyl-3-(cis-hexahydroisoindolin-2-ylcarbonyl) propionate] dihydrate (KAD-1229), which has a potent hypoglycemic effect, in a single reaction vessel. (2S)-2-Benzyl-3-(cis-hexahydroisoindolin-2-ylcarbonyl) propionic acid (7) was directly obtainable from (S)-2-benzylsuccinic acid (2) and cis-hexahydroisoindoline (4), without the isolation of intermediates by the method using thionyldiimidazole (9) and/or diimidazolide of the acid 2. Sequential reaction of imidazole with thionyl chloride, 2, and 4, followed by acid catalyzed hydrolysis gave amidecarboxylic acid 7 in 86% overall yield. The acid 7 was treated with 2 N NaOH, followed by the treatment with calcium chloride to give KAD-1229 in 91% yield.     

Mass spectra of acetylenic fatty acid methyl esters and derivatives

A series of isomeric methyl octadecynoates was analyzed by mass spectrometry; each isomer gave a unique spectrum. The characteristic ions were those resulting from a McLafferty rearrangement of the allenic sites or of the already-rearranged allenic sites. The acetylenic esters were also subjected to oxymercuration whereupon a carbonyl group was formed at either of the original actylenic carbon atoms providing two oxostearates. Further reaction with NaBH4 formed hydroxy esters which, after silylation, gave diagnostic mass spectra indicative of the triple bond location. Applied to esters with both double and triple bonds, this procedure permitted differentiation between the two types of unsaturation. Methoxyl groups marked the original double bond locations and hydroxyls did so for triple bonds.     

Urinary organic acid screening by solid-phase microextraction of the methyl esters

According to ICSD criteria, sleep paralysis (SP) occurs at least once in a lifetime in 40-50% of normal subjects. Variation in the reported incidence could be attributed to the difference in the expression in survey or an influence of cultural background. Some factors assumed to affect the appearance of SP include psychological, biological, developmental, and genetic influences. Sleep onset REM period (SOREMP) is one of the factors which is 'assumed to be related to SP in normal subjects' as well as narcoleptic patients. We conducted an experiment for eliciting SOREMP and SP. Our result indicated a relationship between SOREMP and SP. Polysomnograms during SP were characterized by REM/W stage dissociated states. Other factors which may influence the occurrence of SP are also discussed.     

Antiviral activity of cholesteryl esters of cinnamic acid derivatives

Cholesteryl 3",4"-dimethoxycinnamate (7) and a new synthesized o-coumaroyl ester of 3 beta-(2'-hydroxyethoxy)-cholest-5-en (13) exhibited a marked activity against poliovirus type 1 (Mahoney). Compound 7 showed an approximately 20-fold greater selectivity in its antiviral activity than compound 13. These compounds were selected from thirteen steryl esters of cinnamic acid derivatives through an in vitro antiviral screening against viruses belonging to taxonomic groups with causative agents of important human infectious diseases to which chemotherapy is indicated, i.e. Picornaviridae, Orthomyxoviridae, Paramyxoviridae and Herpesviridae.     

Kinetic resolution of amino acid esters catalyzed by lipases

Racemic amino acids were resolved by lipase via hydrolysis of their esters. Lipases (Pseudomonas lipase from Amano PS, Rhizopus lipase from Serva, and porcine pancrease lipase from Sigma) could selectively hydrolyze the L-amino acid esters in aqueous solution with high reactivities and selectivities. The effect of the structural changes in the ester moiety on the stereoselectivity of the lipases was also investigated using D,L-homophenylalanine as a model. Procedures were developed for the resolution of natural and unnatural amino acids.     

Biodegradation of phthalic acid esters in river water and activated sludge

Infants born in New England with congenital heart defects were examined for association with time of year or population density. Moderate seasonal peaks in births were noted for complex ventricular septal defect, malposition defects, and transposition of the great arteries. Positive associations with population density were found for pulmonary atresia with ventricular septal defect, ventricular septal defect with secondary anomalies, and tricuspid atresia.     

D-lactate production and [14C]succinic acid uptake by adherent and nonadherent Escherichia coli

Escherichia coli isolates of different adherence phenotypes produced different amounts of D-lactate. Alterations of culture conditions did not influence the amount of D-lactate produced. The observed pH decreases in tissue culture medium corresponded with increases in D-lactate concentration. Very little [14C]succinic acid was incorporated into cells during the in vitro incubation of adherent and nonadherent E. coli with HeLa cells, but the amounts of tracer removed from the culture medium by adherent and nonadherent strains differed. The results are further evidence of a difference in the metabolic behavior of adherent and nonadherent E. coli.     

The ecotoxicity and the biodegradability of lactic acid, alkyl lactate esters and lactate salts

The ecotoxicity of lactic acid, its alkyl esters and selected metal salts was studied experimentally with the micro alga Selenastrum capricornutum, the crustacean Daphnia magna and the fish species Brachydanio rerio and Pimephales promelas. In addition, the biodegradation of lactate esters was also studied. The aim of the study was to provide predicted environmental data for additional alkyl homologues and metal salts. The ecotoxicity data are evaluated by means of Structure Activity Relations (SAR), using literature data on a non-polar narcotic mechanism of toxicity as a baseline for comparison. Lactate salts were evaluated by comparison to the toxicity of the metal ion. For the fish and D. magna, it was evident that methyl, ethyl, propyl and to a lesser extent butyl lactate were slightly more toxic in comparison to baseline non-polar narcotic toxicity data. The toxicity tests carried out with lactate-salts demonstrated clearly that the toxicity in standard tests is only determined by the associated cation and not by the lactate part. Lactic acid and its alkyl esters were degraded for more than 60% in the ready biodegradability tests and from the data presented, it is evident that the majority of alkyl lactates are readily biodegradable. The results presented in this study indicate that alkyl lactate esters show some differences in their ecotoxicity when compared to non polar narcotic compounds in but that these differences are generally small. When aquatic toxicity is considered together with their rapid tendency to biodegrade, it is concluded that lactate esters show generally favourable environmental characteristics.     

The catalytic action of cupric and ferric ions in nitric acid leaching of Ni3S2

The kinetics of dissolution of synthetic Ni₃S₂ in nitric acid solution containing ⩽ 2.0 M HNO₃ in the presence of cupric and ferric ions was investigated. The effects of stirring, particle size, temperature and concentration of cupric and ferric ions were examined. Solid residues at various levels of nickel extraction were examined by SEM, X-ray diffraction, electron microprobe and chemical analysis. The constant dissolution rate of Ni₃S₂ was attributed to the electrochemical reaction occurring on the surface of flat-plate type Ni₃S₂ particles. The reaction kinetics were found to be independent of both cupric and ferric ion concentrations up to 1 mM. Cupric ion did not act as a catalyst at temperatures below 60°C. At 80°C cupric and ferric ions show the same catalytic activity. The activation energy in the presence of ferric ions was 103.6 ± 4.2 kJ/mol. A mechanism for Ni₃S₂ dissolution in the presence of cupric and ferric ions is proposed.     

Gas chromatography of dimethylalkylsilyl ether derivatives of bile acid methyl esters

The gas chromatographic separation of the DMAS ether derivatives of ten bile acid methyl esters, namely DMES, DMnPS and DMiPS ethers, have been studied by use of an open tubular glass capillary column, coated with SE-30. The DMAS ether derivatives were eluted in sequence according to the number of hydroxyl groups except of 12-KCDCA, and separated. This contrasts with the poorly resolved gas chromatographic peaks produced by the TMS ether derivatives. The DMES ether derivatives were resolved and baseline separation in 30 min, but those of HCA and 12-KCDCA had similar methylene unit values.     

A dual mechanism for the anticonvulsant action of aminooxyacetic acid

The intramuscular injection of aminooxyacetic acid (AOAA) into mice elevated the concentration of gamma-aminobutyric acid (GABA) in the brain, inhibited glutamic acid decarboxylase activity and delayed the onset of isonicotinic acid hydrazide induced seizures. Analyses of these results and of those obtained previously by the authors and other workers indicated that the anticonvulsant action of AOAA involved two mechanisms. One, involving GABA metabolism, was most effective 6 h after AOAA administration, and the other, not involving GABA, was maximally effective 1.5 h after AOAA injection and was completely absent after 6 h. Depending on the convulsant agent under study, the mechanism of the anticonvulsant action of AOAA was purely of the GABA type, purely of the non-GABA type or a combination of both types.