Leiv K. Sydnes

The chemistry of acylals. Part II. Formation of nitriles by treatment of acylals with trimethylsilyl azide in the presence of a Lewis acid

Abstract When acylals from aliphatic and aromatic aldehydes are treated with trimethylsilyl azide in the presence of titanium(IV) chloride, the latter group of compounds is converted to the corresponding nitriles in good to excellent yields. By-products were not formed.

Chorpromazine-induced increase in dipalmitoylphosphatidylserine surface area in monolayers at room temperature

The Langmuir technique revealed that the surface area of acidic glycerophospholipids (dipalmitoylphosphatidylserine, -glycerol, and dipalmitoylphosphatidic acid) in monolayers increased dramatically when micromolar concentrations of the antipsychotic drug chlorpromazine (CPZ) were present in the subphase. Monolayers of neutral glycerophospholipids (dipalmitoylphosphatidylcholine and -ethanolamine) did not show such a large effect with CPZ. Compared to CPZ, millimolar concentrations of the monovalent cations Li+, K+, Na+, Rb+, and Cs+ did not appear to influence the dipalmitoylphosphatidylserine monolayer, suggesting that the effect of CPZ, a monovalent cationic amphophile, was due to an interaction with the acyl chains of the lipids. In addition, the effect of CPZ was reduced by 150 mM Na+, suggesting that the sodium cations might screen the negatively charged headgroups from an electrostatic interaction with the positively charged drug molecule. Two CPZ analogs, chlorpromazine sulfoxide and CPZ with 2 carbons in the side chain, were also studied. These observations suggest that part of the biological effects of CPZ, being antipsychotic and/or side effects, may be due to CPZs action on the acidic glycerophospholipids in nerve cell membranes.

Composition of the water accommodated fractions as a function of exposure times and temperatures.

The water accommodated fractions (WAFs) of nine oils in seawater have been studied. The oils range from light condensate to heavy crude, and include one highly biodegraded oil and one very wax rich oil. This study has identified large variations in the chemical composition of WAFs, depending on oil type, temperature, and mixing time. Experiments at different temperatures (2-13 degrees C) showed that it takes longer time to reach equilibrium at the lowest temperatures, and that this varies for the different oil types. Oils with higher pour point (wax rich oils) need a longer time to establish WAF in equilibrium than oils with lower pour points (naphthenic oils). At 13 degrees C a mixing time of 48h, as recommended in standard procedures, seems to be sufficient for asphalthenic and paraffinic oils. The results demonstrated that for WAF prepared from an unknown oil, or at lower temperatures, different mixing times should be tested. Since the WAF often is used in toxicity testing, the toxicity might be underestimated if the mixing time is too short.

The chemistry of acylals. Part I. The reactivity of acylals towards Grignard and organolithium reagents

Abstract Aldehyde acylals have been prepared and reacted with Grignard and alkyllithium reagents. Acylals from formaldehyde furnished complex reaction mixtures when reacted with both reagents. Acylals of other aldehydes gave reaction mixtures that consisted mainly of an ester, generated by replacing one of the carboxy groups with the organic part of the organometallic reagent, and regenerated aldehyde. The esters were formed in the highest yields. Yields above 90% were experienced when the acylals were reacted with Grignard reagents under Barbier conditions.

New Regiospecific Synthesis of Tri-and Tetra-Substituted Furans

Beta-acyloxy alpha,beta-unsaturated acetylenic ketones have been shown to react with organocuprate reagents and undergo cyclization followed by dehydration to give substituted furans as the final products. The transformation appeared to be versatile, and tri- and tetra-substituted furans were obtained with regiochemical control in moderate to good yields. The best yields were generally obtained when the reactions were performed around -60 degrees C with substrates and cuprates containing sterically demanding substituents. The proposed mechanism for furan formation has been supported by experiments.

On the formation of short-lived, toxic, water-soluble compounds during illumination of crude oil on seawater

Abstract The toxicity of various oil extracts has been studied using cod eggs as test organisms. The most toxic effect was observed when the eggs were kept underneath the water/oil interface during irradiation. This supports the notion that toxic primary photoproducts with a short life-time are generated when oil on seawater is illuminated.

Seasonal variations in weathering and toxicity of crude oil on seawater under arctic conditions

The present study shows that oil in Arctic marine environment is modified by several processes. From October to February the oil composition is mainly affected by evaporation. During the rest of the year the composition is considerably influenced by photooxidation and subsequent dissolution of polar oxidation products in the water phase. These products are toxic and may represent a hazard to marine organisms in the Arctic spring and summer.

Toxicity and chemical reactivity of naphthalene and methylnaphthalenes

Abstract Newly fertilized sea urchin and fish eggs were exposed to solutions of naphthalene and mono- and disubstituted methylnaphthalenes. The toxic effects were not dependent on the number of methyl groups alone, but rather on their specific ring positions. Comparison with calculated atom and bond reactivity indices indicates that the variation in toxicity is related to differences in electronic properties of the molecules. The results are in favour of an initial atom oriented interaction mechanism of toxicity.

Experimental simulation of chemical transformations of aromatic compounds in sediments

Abstract Hydrous pyrolysis of naphthalene, methylnaphthalenes, dimethylnaphthalenes, and dibenzothiophene has been carried out in the presence of montmorillonite, illite, and chlorite at 235–335°C for 48 h. More than 60% of the organic material was bound so strongly to the inorganic matrix that isolation was impossible. The extractable compounds were recovered starting material and products formed by alkylation, dealkylation, and isomerization of the starting material. The composition of the pyrolyzate was influenced by the temperature and the type of clay mineral. K-montmorillonite and illite exhibit more pronounced absorptive and catalytic effects than Na-montmorillonite and chlorite.

Toxic effects of hydroxylated aromatic hydrocarbons on marine embryos

Abstract Phenol and methyl-substituted phenols were acutely toxic towards sea-urchin and fish eggs in concentrations of 3–30 ppm. Naphthols were considerably more toxic than phenols, killing most embryos even in concentrations of 0.3–3 ppm. Sublethal concentrations of phenols and naphthols caused pigment defects in cod larvae.