Synthèse du mèthyl-1 diformyl-2,3 pyrrole,de la méthyl-1 pyrrolo[2,3-d] pyridazine et de la méthyl-1 oxo-6 (6h)cycloheptatrieno[b] pyrrole

This communication describes the synthesis of l-methyl-2,3-diformylpyrrole. This new compound is used to prepare a new heterocycle, l-methylcyclohepta[b]pyrrol-6-one and thus allows a new synthesis of l-methylpyrrolo[2,3-d]pyridazine.     

Synthèse dc la pyrido[2,3-f] phtalazine et des diformyl-6,7; -4,6; -4,7; -2,4 quinoleines

This article describes the synthesis of a new heterocycle, pyrido[2,3,f]phtalazine and three new diformylquinolincs.     

Synthèse des pyrido[2,3-d] el [3,2-d] -s-triazolo[3,4-f] pyrimidines el de (pyrazolyl-1')-4 pyrido[2,3-d] et [3,2-d] pyrimidines

The synthesis of two new heterocycles is described: pyrido-[2,3-d]-.s-triazolo[ 3,4-f] pyrimidine and pyrido[3,2-d]-.s-triayzolo-[3,4-f] pyrimidine. 4-[I'-Pyrazolyl]pyrido[2,3-d]pyrimidines and 4-[1′-pyrazoly1] pyrido[ 3,2-d] pyrimidine are obtained by the action of 4-hydrazinopyrido[2,3-d]pyrimidine and 4-hydrazinopyrido-[3,2-d]pyrimidine with several β-diketones.     

The developmental pattern of stimulus and response interference in a color-object Stroop task: an ERP study

Background

Several studies have shown that Stroop interference is stronger in children than in adults. However, in a standard Stroop paradigm, stimulus interference and response interference are confounded. The purpose of the present study was to determine whether interference at the stimulus level and the response level are subject to distinct maturational patterns across childhood. Three groups of children (6–7 year-olds, 8–9 year-olds, and 10–12 year-olds) and a group of adults performed a manual Color-Object Stroop designed to disentangle stimulus interference and response interference. This was accomplished by comparing three trial types. In congruent (C) trials there was no interference. In stimulus incongruent (SI) trials there was only stimulus interference. In response incongruent (RI) trials there was stimulus interference and response interference. Stimulus interference and response interference were measured by a comparison of SI with C, and RI with SI trials, respectively. Event-related potentials (ERPs) were measured to study the temporal dynamics of these processes of interference.

Results

There was no behavioral evidence for stimulus interference in any of the groups, but in 6–7 year-old children ERPs in the SI condition in comparison with the C condition showed an occipital P1-reduction (80–140 ms) and a widely distributed amplitude enhancement of a negative component followed by an amplitude reduction of a positive component (400–560 ms). For response interference, all groups showed a comparable reaction time (RT) delay, but children made more errors than adults. ERPs in the RI condition in comparison with the SI condition showed an amplitude reduction of a positive component over lateral parietal (-occipital) sites in 10–12 year-olds and adults (300–540 ms), and a widely distributed amplitude enhancement of a positive component in all age groups (680–960 ms). The size of the enhancement correlated positively with the RT response interference effect.

Conclusion

Although processes of stimulus interference control as measured with the color-object Stroop task seem to reach mature levels relatively early in childhood (6–7 years), development of response interference control appears to continue into late adolescence as 10–12 year-olds were still more susceptible to errors of response interference than adults.     

Transition Metal Ion-binding Properties of a 14-Membered N2O2S2- Macrobicyclic Ligand

The selective liquid–liquid extraction of various transition metal cations from the aqueous phase to the organic phase was carried out using a 14-membered N₂O₂S₂-macrobicycle. Metal picrates such as Pb²⁺, Co²⁺, Zn²⁺, Ni²⁺,Cu²⁺ and Cd²⁺ were used in this extraction studies. It was found that the ligand showed moderate selectivity towards Pb²⁺ only among the other metals. The extraction constant (log K _ex) was determined to be 13.8 for Pb²⁺ complex.     

Identification of minor C18 triene and conjugated diene isomers in hydrogenated soybean oil and margarine by GC-MI-FT-IR spectroscopy

Vegetable oils are partially hydrogenated in order to produce palatable products of suitable plasticity. The constituents of these new dietary products are complex mixtures of fatty acid isomers with different nutritional properties. A rapid method is described for separating and identifying fatty acid methyl ester (FAME) isomers of linolenic (octadecatrienoic, 18:3) acid and of conjugated octadecadienoic (18:2) acid, minor species found in hydrogenated soybean oil and margarine, by capillary gas chromatography-matrix isolation-Fourier transform-infrared (GC-MI-FT-IR) spectroscopy. FAMEs of 18:3 acid isomers in margarine, soybean oil hydrogenated in our laboratory, and isomerized linolenic acid were identified by this method, and MI-FT-IR spectra of FAME geometric isomers of octadecatrienoic and conjugated octadecadienoic acids are reported for the first time. Five major C18 triene GC peaks are found in chromatograms of isomerized methyl linolenate, representing species with tri-cis and tri-trans configurations and three species with cis-trans mixed configurations. FAME isomers with these configurations are also found for a hydrogenated soybean oil having an iodine value of 111. Methyl linolenate (tri-cis) is no longer found when soybean oil is further hydrogenated to an iodine value of 96. IR spectra characteristic of a tri-trans isomer are obtained for two test samples with iodine values of 111 and 96. Besides methyl linolenate, only isomers with a mono-trans di-cis configuration are found for the margarine analyzed. Conjugated cis-trans and trans-trans 18:2 FAME isomers are also found in all the hydrogenated soybean oil and margarine analyzed.     

Rapid determination of total trans fat content--an attenuated total reflection infrared spectroscopy international collaborative study

Interest in trans fat labeling has prompted efforts to develop new, more efficient methods for rapidly and accurately determining trans fat content of foods. A novel and rapid (5 min) attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopic procedure was recently developed and applied to food products. This procedure was voted official method AOCS Cd 14d-99 by the American Oil Chemists' Society in 1999 after testing in a 12 laboratory international collaborative study. The results of the study are described in this paper. Analytical ATR-FTIR results exhibited high accuracy in the range 5-40% trans; results tended to have <2% high bias relative to the gravimetrically determined values. The precision of this internal reflection method was found to be superior to the precision of transmission infrared official methods. It is recommended that the applicability of the ATR-FTIR method be limited to trans levels of >5% (as percent of total fat).