Gas chromatographic determination of estrone,estradiol and estriol in non-pregnancy plasma

Summary A gas Chromatographic method for the determination of estrone, estradiol and estriol in plasma of normal females is described. Purification is done by means of TLC of the free compounds and the acetates and quantitation is achieved by electron capture-gas chromatography of the estrogen heptafluorobutyrates. Experiments on the validation of the method are described along with some examples of its application.

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Zusammenfassung Eine gaschromatographische Methode zur Bestimmung von Östron, Östradiol und Östriol im normalen weiblichen Plasma wurde beschrieben. Die Reinigung erfolgte durch Dünnschichtchromatographie der freien Verbindungen und ihrer Acetate. Die quantitative Bestimmung wurde gaschromatographisch mit Hilfe eines Elektroneneinfangdetektors an Hand der Östrogenheptafluorobutyrate bewerkstelligt. Versuche zur Bewertung dieser Methode sowie Beispiele für ihre Anwendung wurden beschrieben.

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Supported by USPHS Grants AM 09908 and RCDA 5 K 3-AM-31, 321 (S. K.) and a grant from the Ford Foundation.     

(1-Adamantanethio)pyridines and tetrahydropyridines from the reaction of 1-adamantanethiol with pyridine I-oxide in acetic anhydride

The reaction of pyridine 1-oxide with 1-adamantanethiol in acetic anhydride produced a mixture of 2- and 3-(1-adamantanethio)pyridines, 1-aeetyl-2-(1-adamantanethio)-3-hydroxy-4-acetoxy-1,2,3,4-telrahydropyridine and the corresponding 3-acetoxyderivative. Pure substances were separated by means of column chromatography on alumina. The tetrahydropyridines were identified by means of their proton magnetic and mass spectra. 4-(1-Adamantanethio)pyridine was synthesized from 4-chloropyridinc and 1-adamantanethiol. The three isomeric (1-adamantanethio)-pyridines were, each, cleaved by concentrated hydrochloric acid to give 1-chloroadamantane and the corresponding pyridinethiol.     

Carbon-13 spin-lattice relaxation studies of the effect of water on ion-selective electrode membranes

(13)C spin-lattice relaxation studies on bis(2-ethylhexyl) adipate (DOA) plasticized poly(vinylchloride) (PVC) membranes are reported for plasticization levels ranging from 25 to 100 wt% plasticizer. The interaction between DOA and PVC molecules in these membranes appears to involve an entrapment of the plasticizer molecule within the polymer matrix. This is based on the constancy of the characteristic segmental motions of the plasticizer chains throughout the concentration range studied. The segmental mobility of the plasticizer component is modified by water absorption in the membrane. The pattern of characteristic segmental motions of the plasticizer is altered, the effect depending on the amount of added salt in the membrane. The results show water has a weak influence on the microviscosity of the membrane matrix.     

Ionic-liquid-supported peptide synthesis demonstrated by the synthesis of Leu(5)-enkephalin

A new strategy for the synthesis of oligopeptides was developed using an ionic liquid as a soluble support. The efficiency of this ionic liquid-phase approach was demonstrated by the synthesis of a bioactive pentapeptide, Leu(5)-enkephalin, in good yield and reasonable purity. The structures and purities of the reaction intermediates in each step were verified easily by routine spectroscopic analysis, and no chromatographic procedures were needed during the synthesis.     

Comparison of gas chromatographic and high-performance liquid chromatographic assays for the determination of debrisoquine and its 4-hydroxy metabolite in human fluids

A comparison of an established gas chromatographic assay for 4-hydroxydebrisoquine and debrisoquine and a modified high-performance liquid chromatographic assay was made. Both assays used guanoxan as the internal standard and required derivatization of all three compounds with acetylacetone at 96 degrees C for 2.5 h and subsequent ethereal extraction and cleaning steps before chromatographic analysis. For detailed pharmacokinetic studies the gas chromatographic assay was more sensitive in the measurement of low concentrations in plasma, but the liquid chromatographic assay was adequate for phenotyping the 4-hydroxylation of debrisoquine in a population. In the latter assay a mobile phase consisting of 70% methanol in water at pH 3.5 (adjusted with orthophosphoric acid containing 10 mM 1-pentanesulphonic acid was employed (flow-rate 1.5 ml/min) with a pre-column (C8) linked to a reversed-phase muBondapak C18 cartridge in a Z-module. The eluate was detected at 248 nm. With this assay it was observed that the buccal absorption of debrisoquine and 4-hydroxy-debrisoquine was affected by the pH of the buccal medium. This indicates that urinary pH may influence the excretion of both substances at high pH. The debrisoquine-to-4-hydroxydebrisoquine ratio may be dose-dependent.     

Macrocyclic polycther sulfide syntheses. The preparation of thia-crown-5, 6 and 7 compounds

Macroeyclic polyether sulfides have been prepared by reacting an oligoethylene glycol dichloride with a dimercaptan or sodium sulfide as reported in a previous paper (6). The following new compounds were prepared: 1,4,7-trithia(15-crown-5) (1); 1,4,10-trithia(15-crown-5) (II): 1,4,7,10-tetrathia(15-crown-5) (III); I-thia(18-crown-6) (IV); 1,4-dithia(18-crown-6) (V); 1,7-dithia(18-crown-6) (VI); 1,4,7-trithia(18-crown-6) (VII); 1,7-dithia(21-crown-7) (VIII); and 1,4,7-trithia(21-crown-7) (IX). The melting points of these and previously reported thia-crown compounds correlate with their structures. X-ray analyses of two thia-crown compounds indicate that the large sulfur atoms are directed away from the center of the ring.     

Octahedral cobalt(III) complexes of the chloropentammine type. XXVII. Effects of Methyl Substituents on reactivities of the cis-chloro-n-propylaminebis(ethylenediamine)-cobalt(III) cation

Salts of one isomeric form of the chloro-n-butylamine-, chloro-iso-butyl-amine- and chloro-sec-butylamine-bis(ethylenediamine)cobalt(III) cations have been prepared and characterised to have a cis-configuration (IR and VIS spectroscopy). Rate constants for their spontaneous aquation, mercury(II)-induced aquation and base hydrolysis have been determined and the activation parameters calculated. The results are compared with data obtained for the n-propylamine complex with a view to investigate the effects of methyl (α, β, γ) substituents on reactivities. The rate-determining dissociation of the outgoing group (Cl^? or HgCl⁺) takes place via either a square-pyramidal or a trigonal-bipyramidal intermediate, depending on whether the activation entropy is negative or positive.     

Solution properties of polyoxymethylene

Light scattering and viscosity have been measured at 25°C. for dilute solutions of six unfractionated polyoxymethylene samples in the mixed solvent hexafluoroacetone–water (mole ratio 1/1.7) slightly buffered with triethylamine. Dialysis equilibrium through porous Vycor glass thimbles indicates that the polymer is strongly solvated by the hydrate (CF₃)₂C(OH)₂, and this must be taken into account in evaluating weight-average molecular weights from the light-scattering data. Over the molecular weight range 23,000–185,000, the intrinsic viscosities (in deciliter per gram) follow the relation The corresponding unperturbed dimensions are σ = 2.3 ± 0.2 or r₀²/nl² = 10.5 ± 1.5.