Synthese d'lsosélénazoles et de benzisosélénazoles-1,2

A general preparation of the isoselenazole ring by addition of bromine followed by ammonia on cis-β–methylseleno-2-propenal is described. This reaction was successfully applied to 1,2-benz-isoselenazole, a new heterocyclic system.     

Microchemical investigation of medicinal plants. XV

Summary A method is described for the determination of alkaloids in morning glory leaves by means of spectrophotofluorimetry. The total alkaloidal contents found in different batches of leaves ranged from 0.027 to 0.04%.

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Zusammenfassung Ein Verfahren zur Bestimmung der Gesamtalkaloide in den Blättern vonIpomoea violacea wurde angegeben. Spektralfluoreszenzmessungen ergaben für verschiedene Chargen solcher Blätter Gehalte von 0,027 bis 0,04%.

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For part XIV see Mikrochim. Acta [Wien]1976 I, 227.     

Co2(CO)8 Catalyzed reaction of oxetanes with trialkylsilanes

Dicobalt octacarbonyl catalyzed silyl-hydroformylation of oxetanes can be controlled by the choice of trialkylsilane. Triethylsilane gives 1,4-$\text{bis}$-silyl ethers while $\text{t}$-butyl-dimethylsilane yields silyl enol ethers.     

1H-CRAMPS Solid-State NMR and X-Ray Crystal Studies of Inclusion Complexes Formed from 3,3′-bis(9-Hydroxy-9-fluorenyl)-2,2′-binaphthyl Hosts with Acetone

The crystal structures of inclusion compounds of 3,3-bis(9-hydroxy-9-fluorenyl)-2,2-binaphthyl host (1) and its chloro (2) or bromo (3) derivatives substituted in 2,7-positions of the fluorene units with acetone guests (1A–3A) were determined by X-ray studies as well as by ¹H-CRAMPS solid-state NMR. Using this NMR technique allows identification of differently bound guest molecules due to their different chemical shifts caused by the influence of the ring current effects of the host aryl units.     

Rotationally resolved ultraviolet spectra of benzene-noble gas van der Waals clusters

Sub-Doppler electronic spectra with hundreds of resolved rotational lines are now available for benzene-Ar dimers and trimers. From their analysis the structure of these clusters is precisely determined. The analysis of two bands, 6 ₀ ¹ and 16 ₀ ² , of C₆H₆ · Ar is presented in detail. It leads to accurate values of the van der Waals bond length in the electronic ground and excited state. The change in frequency upon clustering is found to be a factor of 17 larger for the overtone of the out-of-plane modev ₁₆ than for the in-plane vibrationv ₁. This can be tentatively explained by an interaction of the low frequency out-of-plane motion of the ring with the van-der-Waals motion of the Ar atom.     

Screening,library-assisted identification and validated quantification of fifteen neuroleptics and three of their metabolites in plasma by liquid chromatography/mass spectrometry with atmospheric pressure chemical ionization

A liquid chromatographic/mass spectrometric assay with atmospheric pressure chemical ionization (APCI-LC/MS) is presented for the fast and reliable screening and identification and for the precise and sensitive quantification of 15 neuroleptic (antipsychotic) drugs and three of their relevant metabolites in plasma. It allows confirmation of the diagnosis of a neuroleptic overdose and monitoring of psychiatric patients' compliance. The neuroleptics amisulpride, bromperidol, clozapine, droperidol, flupenthixol, fluphenazine, haloperidol, melperone, olanzapine, perazine, pimozide, risperidone, sulpiride, zotepine and zuclopenthixol and the pharmacologically active metabolites norclozapine, clozapine N-oxide and 9-hydroxyrisperidone were extracted from plasma using solid-phase extraction and were separated on a Merck LiChroCART column with Superspher 60 RP Select B as the stationary phase. Gradient elution was performed using aqueous ammonium formate and acetonitrile. After screening and identification in the scan mode using the authors' new LC/MS library, the neuroleptics were quantified in the selected-ion mode. The quantification assay was fully validated. It was found to be selective and proved to be linear from sub-therapeutic to over therapeutic concentrations for all analytes. The corresponding reference levels are listed. The accuracy and precision data were within the required limits. The analytes were stable in frozen plasma for at least 1 month. The method was successfully applied to several authentic plasma samples from patients treated or intoxicated with various neuroleptics. The validated LC/MS assay has proved to be appropriate for the isolation, separation, screening, identification and quantification of various neuroleptics in plasma for clinical toxicology and therapeutic drug monitoring purposes.     

Kinetics of the γ-radiation-induced polymerization of methyl methacrylate in the solid state

Studies have been made of the γ-radiation-induced polymerization of methyl methacrylate in bulk, in the solid state at a temperature of ?65°C. and a radiation intensity of 346,000 rad/hr. The reaction was found to have an extremely long induction period (～50 hr.) when pure monomer was used, and to be first-order with respect to polymer concentration. This first-order dependency was confirmed by a series of irradiations in which 0.6% poly(methyl methacrylate) was dissolved in the monomer before irradiation. These irradiations showed no induction period. Nuclear magnetic resonance spectroscopy indicated a much more heterotactic polymer than that obtained in the liquid state at ?49°C.     

A convenient synthesis of 1,3-oxazolidin-4-ones and 1,3-oxazin-4-ones

1,3-Oxazolidin-4-ones and 1,3-oxazin-4-ones were synthesized by formal cyclocondensation of imines with α- or β-hydroxy acids.     

A Study of the 13C NMR Shifts in Two Tetradehydrocyclodecabiphenylenes and Related Aryl and Biphenylenylacetylenes

The ¹³C spectra of 5,6,9,10-tetradehydrocyclodeca[1,2,3,4-def]-benzo [7,8]biphenylene, 1, and 5,6,9,10-tetradehydrocyclodeca [1,2,3,4-def]-naphtho [2,3-7,8]biphenylene, 2, are reported as are those of a number of simpler acetylenic hydrocarbons used as spectral references. Most of the shifts can be assigned unambiguously. The acetylenic shift assignments were verified by ortho-proton, sp-carbon (¹H(1)-¹³C_sp(3)) decoupling experiments. A simple additive shift correlation is found for the hydrocarbons containing unstrained acetylenic groups. However, significant discrepencies are found for the ¹³C shifts for the strained hydrocarbons 1, 2, 1,2-bis(phenylethynyl)-benzene, 12, and 2,3-bis(phenylethynyl)-naphthalene, 13. The discrepencies are particularily large for carbons near the triple bonds and are attributed to a combination of strain, rehybridization, and other proximity effects related to the interaction between the ortho-substituted acetylenic carbons.     

The amperometric detection of thyroid hormones following reverse-phase high-performance liquid chromatography

The principle of an assay of the major thyroid hormones by an electrochemical technique is demonstrated. The separation of 3,3',5-triiodothyronine, 3,3',5'-triiodothyronine, and thyroxine, by reverse-phase high-performance liquid chromatography is followed by their electrochemical oxidation in a thin-layer electrochemical detection cell with a low-temperature isotropic carbon working electrode. The limits of detection found were in the subnanogram range with linear response in the ranges 0–125 ng for T₃ and 0–500 ng for T₄. The approach makes the simultaneous assay of total serum thyroid hormones feasible.