Jan Skramstad

Enrichment of chlorinated fatty acids in fish lipids prior to analysis by capillary gas chromatography with electrolytic conductivity detection and mass spectrometry

Abstract Chlorinated carboxylic acids of fatty acid character have been shown to account for up to 90% of the extractable, organically bound chlorine (EOCl) in fish. To facilitate the detection of chlorinated fatty acid methyl esters (FAMEs) released from fish lipids, an enrichment was performed by removing the polyunsaturated FAMEs and saturated, straightchain FAMEs through their complexation with silver ions and urea, respectively. The resulting about 30-fold increase in the concentration of chlorinated FAMEs allowed for their analysis, by gas chromatography (GC) with halogen-selective electrolytic conductivity detection, in lipids containing only 30 ppm (m/m) of EOCl. Following additional purification by thin-layer chromatography, methyl esters of dichlorotetradecanoic, dichlorohexadecanoic and dichlorooctadecanoic acids were indicated by GC-ammonia positive ion chemical ionisation mass spectrometry in a fish sample containing 1200 ppm (m/m) of EOCl.

Distribution of 14C from ingested, radiolabelled dichlorostearic, stearic and oleic acids in body and in lipids of perch, Perca fluviatilis

Distribution of C-14 from ingested, radiolabelled dichlorostearic, stearic and oleic acids in body and in lipids of perch, Perca fluviatilis

OLIGOTHIOPHENES. I. A FACILE SYNTHESIS OF BIS(2,2′-BITHIENYL)METHANES

ABSTRACT This paper describes an efficient method for the synthesis of bis(2,2′-bithienyl)methanes from 2,2′-bithienyl. In one case when the method gave an unexpected result, the product was determined by X-ray crystallography.

Oligothiophenes II: Synthesis and Stability of 5‐Methylenethiophen‐2(5H)‐ones

Abstract This article describes an improved synthesis of substituted 5‐methylenethiophen‐2(5H)‐ones. These compounds are characterized by an unusual lack of reactivity as demonstrated by a number of unsuccessful reactions. The reason for this is suggest. The products were analyzed by UV, IR, NMR, and MS and by x‐ray crystallography.

Oligothiophenes III: Synthesis of tetra-thienyl-substituted ethylenes including an abnormal McMurry coupling result

Abstract This article describes the synthesis of some selected tetra‐thiophenyl‐substituted ethenes by McMurry coupling of some selected thienyl ketones, including a surprising coupling product. The products were analyzed by MS, NMR, UV, and x‐ray crystallography. Their cyclic voltagrams were recorded.

Pyrolysis of Cyclic Polyoxo Phosphorus Ylides

In an extension of our recent work on generating acetylenic amino acid derivatives by flash vacuum pyrolysis (FVP) of appropriate stabilised phosphorus ylides,1 we examined the ylides 1 with a free amino group. Rather than the expected acetylenic product these gave the novel cyclic ylides 2 with loss of ethanol. Preliminary attempts to bring about extrusion of Ph3PO from these gave rather confusing results so we have examined simpler cyclic ylides in an attempt to understand the processes involved.

PHOSPHORUS IN ORGANIC SYNTHESIS. THE TANIGAWA REACTION REVISITED AS A METHOD FOR CONVERTING ALCOHOLS TO TERTIARY AMINES

Abstract Contrary to earlier observations, N-methyl-N-phenylaminotriphenylphosphonium iodide 1 (the Murahashi reagent) does not react with alcohols and primary or secondary amines under mild conditions (80°) to give secondary or tertiary amines. However the reaction can be successfully performed at higher temperatures. A mechanistic scheme implying initial amine exchange between 1 and the added amine leading to the N,N-dimethyl analog 5 is suggested. An improved synthesis where the reactive intermediate 5 is formed in situ from triphenylphosphine, carbon tetrachloride and HNR3R4 is described.

An Improved Synthesis of the Antiulcer Drug Ranitidine from N‐[2‐[[[5‐(hydroxymethyl)‐2‐furanyl]‐methyl]‐thio]‐ethyl]‐N′‐methyl‐2‐nitro‐1,1‐ethenediamine

An improved synthesis of the antiulcer drug ranitidine from N‐[2‐[[[5‐(hydroxymethyl)‐2‐furanyl]‐methyl]‐thio]‐ethyl]‐N′‐methyl‐2‐nitro‐1,1‐ethenediamine is reported.

A MILD AND EFFICIENT METHOD FOR HYDROHALOGENATION OF UNSATURATED FATTY ACIDS AND ESTERS

Abstract Unsaturated fatty acids and esters are converted in quantitative yield to a mixture of mono halogenated fatty acids and esters by treatment with liquid hydrogen chloride or hydrogen bromide.

Metabolic fate of 14 C-labelled chlorinated and non-chlorinated fatty acids in goldfish ( Carassius auratus )

In order to study the metabolic fate of chlorinated fatty acids in fish, goldfish were fed either 9,10-dichlorostearic acid or oleic acid, chosen as the unchlorinated analogue, both radiolabelled at either the carboxyl (1st) or the terminal (18th) carbon of the fatty acid chain. By keeping the fish in hermetically closed aquaria, all the respired, assimilated and excreted radioactivity could be accounted for. Fish fed 9,10-dichlorostearic acid labelled in the terminal end respired radioactive CO2 to a much lower degree than fish fed the other test compounds. As a consequence, the radioactivity bound in lipids was higher in the group of fish fed dichlorostearic acid labelled in the terminal end. It is suggested that the chlorine atoms in the middle of the carbon chain obstruct the metabolic turn-over of 9,10-dichlorostearic acid, which may have an impact on the residence time of these compounds in the ecosystem.