Determination of noscapine in plasma by liquid chromatography

A liquid chromatographic method has been developed for the determination of noscapine in plasma. Noscapine and the internal standard, papaverine, were extracted into methylene chloride by column extraction. The separation was performed on a straight-phase liquid chromatographic system using a mobile phase of hexane--methanol--chloroform--diethylamine. A high detection selectivity was obtained by UV detection at 310 nm. The precision of the method was 3.8% (standard deviation) at a level of 89 ng/ml and 9.5% (standard deviation) at 5.9 ng/ml. The selectivity of the analytical method was evaluated by comparing analytical results after isolation of extracts of plasma samples on reversed- and straight-phase liquid chromatographic systems.     

Arbeiten über Phosphorsäure- und Thiophosphorsäureester mit einem heterocyclischen Substituenten. 7. Mitteilung. Thio- und Dithiophosphorsäureester von der Art des GS 13005 mit einem analogen oder homologen heterocyclischen Ring

To complete results presented in this and in previous papers of this series as well as published in patents of other authors a review is given on known and new variations of the heterocyclic moiety in GS 13005 type thio- and dithiophosphoric acid esters ( 1, 2 ) by modification of the 1,3,4-thiadiazol-2(3H)-one ring 5 and by its replacement by analogue five- and homologue six-membered rings. Among new esters of this type some containing the pyrazolinone ring 3 or a 2-alkoxy-4H, 6H-1,3,4-thiadiazin-5-one ring 10 (homologue of the original 5-methoxy-1,3,4-thiadiazol-2(3H)-one ring in GS 13005) show no remarkable pesticidal activity, some others containing a pyrazolering 7 or a 3(2H)-pyridazinonc ring 8 are moderately to highly active but toxic to inauinials in the same proportion. Attempts to prepare seven-membered 2-alkoxy- and 2-alkylthio-6,7-dihydro-l, 3,4-thiadiazepin-S(4H)-ones 11 , Z-rnethoxy-l,3,4-thiadiazepin-S(4H)-one 12 (ring vinylogue of the original 5-methoxy-l,3,4-thiadIazol-2(3H)-one ring in GS 13005) and its 7-methyl-derivative have been unsuccessful due to unexpected side reactions, such as: five-ring closure of 3-(3-chloropropionyl)-thio- and -dithiocarbazic acid esters 22 to pyrazolidinone derivatives 23 , pyrazolinone ring closure of a 3-(acetoacety1)-thiocarbazic acid O-methyl ester derivative 26 , bromine attack on sulfur in 3-(2-alkenoyl)-thiocarbazic O-methyl esters 29 instead of bromine addition at the double bond, and halogen splitting off without ring closure in 3-(2,3-dihalogeno-alkanoyl) -thiocarbazic O-methyl esters 30 prepared by acylation of thiocarbazic acid O-methyl ester with dihalogeno-alkanoyl-chlorides.     

Thermodynamische Untersuchungen im System Gold—Cadmium

Zusammenfassung Flüssige und feste Legierungen im System Au–Cd wurden von 60 bis 90 At% Cd zwischen 653° und 873°K mit derEMK-Methode untersucht und thermodynamische Eigenschaften berechnet. Die Aktivitäten von Cd zeigen stark negative Abweichungen vom idealen Verhalten. Die partiellen molaren Enthalpien sind negativ und verschieben sich mit zunehmender Temperatur zu weniger negativen Werten, die partiellen molaren Entropien sind positiv und nehmen mit zunehmender Temperatur zu. Aus eigenen Werten und Literaturdaten wurden integrale thermodynamische Größen für die Schmelzen im gesamten System Au–Cd bei 1000°K berechnet. Für einige feste Cd-reiche Phasen wurden ebenfalls Aktivitäten erhalten und aus den Knickpunkten derEMK-Temperatur-Kurve Temperaturen von Phasenübergängen bestimmt.

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Thermodynamic investigations in theAu–Cd-system

Liquid and solid alloys in the Au–Cd system were investigated between 60 and 90 at % Cd and 653°–873°K by theemf method, and thermodynamic properties were calculated. The activities of Cd exhibit strong negative deviations from ideal behavior. Partial molar enthalpies are negative and become less so with increasing temperature; partial molar entropies are positive and increase with increasing temperature. A consistent set of integral thermodynamic data for liquid solutions of the entire Au–Cd system at 1000°K were calculated using values taken from the literature. Activities for some solid Cd-rich phases were also obtained. From discontinuities in theemf vs. temperature curve temperatures of phase transitions were determined.

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Mit 5 Abbildungen

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Herrn Prof. Dr.H. Nowotny gewidmet.     

Phosphaniminato-Komplexe des Iods. Synthese und Kristallstrukturen von Ph3PNIO2 und Ph3PNSiMe3 · I2

Phosphoraneiminato Complexes of Iodine. Syntheses and Crystal Structures of Ph₃PNIO₂ and Ph₃PNSiMe₃ · I₂ Ph₃PNIO₂ has been prepared as yellow crystals by the reaction of Ph₃PNSiMe₃ with I₂O₅ in boiling acetonitrile, whereas the molecular complex Ph₃PNSiMe₃ · I₂ is formed as brown crystals by the reaction of Ph₃PNSiMe₃ with iodine in acetonitrile solution. Both complexes were characterized by crystal structure determinations. Ph₃PNIO₂: Space group P2₁/n, Z = 4, 2 858 observed unique reflections, R = 0.039. Lattice dimensions at 19°C: a = 972.8(2), b = 1 743.4(3), c = 1 073.7(2) pm, β = 115.46(3)°. The compound forms monomeric molecules with pyramidal geometry at the iodine atom. The bond angle PNI (126.9°) is unusually small; the PN bond length of 159.2 pm corresponds with a double bond. Ph₃PNSiMe₃ · I₂: Space group P1 , Z = 2, 3 560 observed unique reflections, R = 0.033. Lattice dimensions at 19°C: a = 941.2(2), b = 1 041.7(2), c = 1 287.4(3) pm, α = 78.34(1)°, β = 72.00(2)°, γ = 86.08(2)°. The compound forms monomeric molecules, in which the I₂ molecule and the nitrogen atom of the phosphoraneimine molecule realize a linear N? I? I axis with a bond length N? I of 243.2 pm.     

Stereoselectivity of the Radical Reductive Alkylation of Enamines: Importance of the Allylic 1,3-Strain Model

Radical addition to enamines using Bu₃SnH as reducing agent are reported (Schemes 2 and 4). The diastereoselectivity of these reactions was examined in different systems (Tables 1 and 2). Enamines derived from cyclic ketones such as cyclohexanone were alkylated with high diastereoselectivity with preferential formation of the cis-disubstituted cycloalkanes. In acyclic systems such as enamines derived from propiophenone and diethyl ketone, moderate to high stereoselectivities were observed in the H-abstraction step. A model based principally on minimization of allylic 1,3-strain (A^1,3 strain) was deduced from the experimental results and semi-empirical (AM1) calculations.     

N- and C-sulfenylation of 1-(1,2-oxazol-3 (and 5)-yl)-3-alkylureas with organic sulfenyl chlorides

Condensation of chlorocarbonylsulfenyl chloride 1 with 1-(5-(1,1-dimethylethyl)-1,2-oxazol-3-yl)-3-methylurea 4a has been found to give isomeric 2,4-disubstituted-1,2,4-thiazolidine-3,5-diones 5 and 6 . Assignments are confirmed by the X-ray structure data of 6 . Sulfenylation with alkoxycarbonylsulfenyl chlorides 7 and trichloromethylsulfenyl chloride 10 of 4 occurs exclusively on N-1 rather than N-3 of the urea moiety. With the isomeric 1-[3-(1,1-dimethylethyl)-1,2-oxazol-5-yl]-3-methylurea 14 and ethoxycarbonylsulfenyl chloride 7b , C-sulfenylated derivatives 15 and 16 are formed in low yield.     

The Photochemistry of 2-Cyclopentenyl Methyl Ketones

2-Cyclopentenyl and 3-phenyl-2-cyclopentenyl methyl ketones (15–18, 30, 31) undergo a 1,3-acetyl shift on direct irradiation, and the oxa-di-π-methane rearrangement to photochemically non-interconverting endo and exo bicyclo-[2.1.0]pentyl methyl ketones on triplet sensitization. Exceptions include the 2-methyl-3-phenyl-2-cyclopentenyl methyl ketone 32 and the 1-phenyl-2-cyclo-pentenyl methyl ketone 44 which are unreactive on direct irradiation and on triplet sensitization, respectively, and the 2-phenyl-2-cyclopentenyl methyl ketones 42 and 43 which do not react under either condition. The reactive triplet of the 3-phenyl-2-cyclopentenyl methyl ketone 30 has been identified as the localized styrene π,π*-state of E_T=59 kcal/mol by comparison of its phosphorescence at 77K in rigid glasses with that of 1-phenyl-cyclopentene, and by the independence of the quantum yield on sensitizer energy in the range of 61–74 kcal/mol.     

A complexometric method for the determination of small amounts of an alkaline-earth metal in mixture with other metals

A discussion of the conditions for the complexometric determination of the minor component in a mixture of two metal ions is presented. It is based on expressions of the Ringbom type for the titration error. These are derived by the use of logarithmic diagrams. The results have been used to devise an analytical procedure for the determination of the alkaline earth metals in the presence of a large excess of nickel or zinc.     

Synthesis of 2,3-dihydro-1H-imidazo[1,2-b]pyrazoles

Two novel 2,3-dihydro-1H-imidazo[1,2-b]pyrazole derivatives 7 and 8 have been prepared by hydrazinolysis with 2,4-dinitrophenylhydrazine of 1-(benzylideneamino)-2-(2-ethoxycarbonyl-2-nitromethylidene)-imidazolidine 4 . The precursor 4 was conveniently prepared from ethyl nitroacetate and 1-(benzylidene-amino)-2-(methylthio)imidazoline 3 . Two examples are presented in which ethyl aceto(and trifluoroaceto)acetate 2-nitrophenyl-hyrazone, 9 and 10 , both of which also feature the β-hydrazinoacrylate arrangement, are refluxed in ethanol containing hydrochloric acid and thereby converted into pyrazolones 11 and 12 , pyrazoles 13 and 14 , and ketone 2-nitrophenylhydrazones 15 and 16 , respectively.     

{2,2′‐[1,1′‐(4‐Aza­heptane‐1,7‐diyl­dinitrilo)diethyl­idyne]­diphenolato}­copper(II)

The quinquedentate ligand 2,2′‐[1,1′‐(4‐aza­heptane‐1,7‐diyl­dinitrilo)diethyl­idyne]diphenol in the title compound, [Cu(C₂₂H₂₇N₃O₂)], furnishes an N₃O₂ donor set, which results in a distorted square‐pyramidal coordination; the two O and two imine N atoms lie in the basal plane, while the secondary amine N atom of the ligand occupies the axial position. The axial Cu—N bond is 0.33 Å longer than the average of the equatorial bonds, and the O atoms are trans. The symmetry of the mol­ecule is lowered by the twist–boat and chair conformations adopted by the two CuNN chelate rings. The complex contains two intra­molecular C—H⋯O inter­actions, and two mol­ecules of the complex are linked into a dimer by means of moderate N—H⋯O hydrogen bonds. Spectroscopic evidence supports the presence of hydrogen bonds.